TY - BOOK AU - Aasen, S. PY - 2008 BT - Utholdenhet-trening som gir resultater CY - Oslo, Norway PB - Akilles Forlag N1 - Utholdenhet-trening som gir resultater SN - 978-82-7286-145-1 N1 - 915 N1 - Utholdenhet- trening som gir resultater ID - 42 ER - TY - JOUR AU - Acevedo, E. O. AU - Goldfarb, A. H. PY - 1989 TI - Increased training intensity effects on plasma lactate, ventilatory threshold, and endurance SP - 563-8 N1 - Oct JF - Med Sci Sports Exerc VL - 21 IS - 5 N1 - Increased training intensity effects on plasma lactate, ventilatory threshold, and endurance N1 - 588 N1 - 2607946 Acevedo, E O Goldfarb, A H Research Support, Non-U.S. Gov't United states Medicine and science in sports and exercise Med Sci Sports Exerc. 1989 Oct;21(5):563-8. KW - Adult Humans Lactates/*blood Lactic Acid Male Oxygen Consumption/*physiology *Physical Education and Training Physical Endurance/*physiology *Running N2 - The purpose of this study was to determine the effects of increased training intensity (ITI) on VO2max, plasma lactate accumulation, ventilatory threshold (VT), and performance in trained distance runners. Seven trained male distance runners increased their training intensity three d.wk-1 at 90-95% HRmax for eight wk. ITI did not alter VO2max (65.3 +/- 2.3 vs 65.8 +/- 2.4 ml.kg-1.min-1) but improved 10 km race time (means = 63 s decrease) and increased run time to exhaustion on the treadmill at the same speed and grade (means = 3.88 min). Significant decreases in plasma lactate concentration at 85 and 90% of VO2max were observed after ITI. No differences were found in plasma lactate at 65, 70, 75 or 80% of VO2max or VT following ITI. Significant correlations were obtained between 10 km race times and changes in plasma lactate at 85 and 90% of VO2max (r = 0.69 and 0.73, respectively). Lactate accumulation at both 2.5 and 4.0 mM were at a significantly greater percent of VO2max after ITI. Additionally, the changes in plasma lactate were dissociated from alterations in VT after ITI. These data indicate that previously trained runners can increase training intensity to improve endurance performance by lowering lactate at the intensity at which they trained despite no changes in VO2max and VT. AD - Exercise Science Laboratory, University of North Carolina, Greensboro 27412. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=2607946 ID - 96 ER - TY - JOUR AU - Achten, J. AU - Jeukendrup, A. E. PY - 2003 TI - Maximal fat oxidation during exercise in trained men SP - 603-8 N1 - Nov JF - Int J Sports Med VL - 24 IS - 8 N1 - Maximal fat oxidation during exercise in trained men N1 - 1065 N1 - 14598198 Achten, J Jeukendrup, A E Clinical Trial Research Support, Non-U.S. Gov't Validation Studies Germany International journal of sports medicine Int J Sports Med. 2003 Nov;24(8):603-8. KW - Adipose Tissue/*metabolism Adult Body Composition/physiology Clinical Protocols Confidence Intervals Exercise/*physiology Exercise Test/methods/standards Humans Male Oxidation-Reduction Oxygen Consumption/physiology Physical Fitness/physiology Reproducibility of Results N2 - Fat oxidation increases from low to moderate exercise intensities and decreases from moderate to high exercise intensities. Recently, a protocol has been developed to determine the exercise intensity, which elicits maximal fat oxidation rates (Fat(max)). The main aim of the present study was to establish the reliability of the estimation of Fat(max) using this protocol (n = 10). An additional aim was to determine Fat(max) in a large group of endurance-trained individuals (n = 55). For the assessment of reliability, subjects performed three graded exercise tests to exhaustion on a cycle ergometer. Tests were performed after an overnight fast and diet and exercise regime on the day before all tests were similar. Fifty-five male subjects performed the graded exercise test on one occasion. The typical error (root mean square error and CV) for Fat(max) and Fat(min) was 0.23 and 0.33 l O(2) x min(-1) and 9.6 and 9.4 % respectively. Maximal fat oxidation rates of 0.52 +/- 0.15 g x min(-1) were reached at 62.5 +/- 9.8 % VO(2)max, while Fat(min) was located at 86.1 +/- 6.8 % VO(2)max. When the subjects were divided in two groups according to their VO(2)max, the large spread in Fat(max) and maximal fat oxidation rates remained present. The CV of the estimation of Fat(max) and Fa(min) is 9.0 - 9.5 %. In the present study the average intensity of maximal fat oxidation was located at 63 % VO(2)max. Even within a homogeneous group of subjects, there was a relatively large inter-individual variation in Fat(max) and the rate of maximal fat oxidation. AD - School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=14598198 ID - 43 ER - TY - JOUR AU - Ahmetov, II AU - Rogozkin, V. A. PY - 2009 TI - Genes, Athlete Status and Training - An Overview SP - 43-71 JF - Med Sport Sci VL - 54 N1 - Genes, Athlete Status and Training - An Overview N1 - 937 N1 - 19696507 Journal article Medicine and sport science Med Sport Sci. 2009;54:43-71. Epub 2009 Aug 17. N2 - Significant data confirming the influence of genes on human physical performance and elite athlete status have been accumulated in recent years. Research of gene variants that may explain differences in physical capabilities and training-induced effects between subjects is widely carried out. In this review, the findings of genetic studies investigating DNA polymorphisms and their association with elite athlete status and training responses are reported. A literature search revealed that at least 36 genetic markers (located within 20 autosomal genes, mitochondrial DNA and Y-chromosome) are linked to elite athlete status and 39 genetic markers (located within 19 genes and mitochondrial DNA) may explain, in part, an interindividual variability of physical performance characteristics in response to endurance/strength training. Although more replication studies are needed, the preliminary data suggest an opportunity to use some of these genetic markers in an individually tailored prescription of lifestyle/exercise for health and sports performance. AD - Sports Genetics Laboratory, St Petersburg Research Institute of Physical Culture, St. Petersburg, Russia. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=19696507 ID - 83 ER - TY - JOUR AU - Altman, D. G. AU - Schulz, K. F. AU - Moher, D. AU - Egger, M. AU - Davidoff, F. AU - Elbourne, D. AU - Gotzsche, P. C. AU - Lang, T. PY - 2001 TI - The revised CONSORT statement for reporting randomized trials: explanation and elaboration SP - 663-694 JF - Annals of Internal Medicine VL - 134 N1 - The revised CONSORT statement for reporting randomized trials: explanation and elaboration N1 - 43 ID - 132 ER - TY - BOOK AU - Anonymous PY - 2001 BT - Publication Manual of the American Psychological Association CY - Washington DC PB - APA N1 - Publication Manual of the American Psychological Association N1 - 9 N1 - 5th almost full KW - authors instructions ID - 130 ER - TY - JOUR AU - Åstrand, I. AU - Åstrand, P. O. AU - Christiensen, E. H. AU - Hedman, R. PY - 1960 TI - Intermittent muscular work SP - 448-453 JF - Acta Physiolologica Scandinavica VL - 48 N1 - Intermittent muscular work N1 - 841 ID - 119 ER - TY - JOUR AU - Åstrand I, Å P. Christiansen E. H. Hedman R. PY - 1960 TI - Myohemoglobin as an oxygen store in man SP - 454-460 JF - Acta Physiolologica Scandinavica VL - 48 N1 - Myohemoglobin as an oxygen store in man N1 - 842 ID - 118 ER - TY - CHAP AU - Åstrand, P. O. Rodahl K. R. PY - 1986 BT - Textbook of Work Physiology CT - Physical Training CY - Singapore PB - McGraw-Hill CP - 3rd SP - 412-476 N1 - Physical Training N1 - 1401 ID - 117 ER - TY - BOOK AU - Bartlett, R PY - 2007 BT - Introduction to Sports Biomechanics: Analyzing Human Movement Patterns CY - London, UK PB - Routledge VL - 2nd N1 - Introduction to Sports Biomechanics: Analyzing Human Movement Patterns ID - 20 ER - TY - JOUR AU - Batterham, A. M. AU - Hopkins, W. G. PY - 2005 TI - A decision tree for controlled trials SP - 33-39 JF - Sportscience VL - 9 N1 - A decision tree for controlled trials N1 - 37 KW - analysis, bias, crossover, randomized N2 - A controlled trial is used to estimate the effect of an intervention. We present here a decision tree for choosing the most appropriate of five kinds of con-trolled trial for numeric outcome measures. A time series or quasi-experimental design is used when there is no opportunity for a separate control group or control treatment. In this design, the weakest of the five, a series of measurements taken before the intervention serves as a baseline to estimate change resulting from the intervention. In trials with a separate control group, the usual design is a fully controlled parallel-groups trial, in which subjects are measured before and after their allocated control or experimental treatment. A posts-only design, in which subjects are measured only after their treatment, can be more efficient when poor reliability of the outcome measure over the time frame of the intervention makes large sample sizes unavoidable. Cross-over studies, in which all the subjects receive all the treatments, are an option when the effects of the treatments wash out in an acceptable time. In fully con-trolled crossovers, subjects are measured before and after each treatment, whereas measurements are taken only after each treatment in a simple cross-over. Fully controlled crossovers, arguably the best of the five designs, are more efficient if the outcome measure becomes too unreliable over the wash-out period, and they provide an assessment of the effect of the treatment on each subject. In simple crossovers, individual assessment is possible only by including a repeat of the control treatment. AD - School of Health and Social Care, University of Teesside, Middlesbrough, UK; Sport and Recreation, AUT University, Auckland 1020, New Zealand. Email: will=AT=clear.net.nz UR - http://sportsci.org/jour/05/wghamb.htm ID - 153 ER - TY - JOUR AU - Batterham, A. M. AU - Hopkins, W. G. PY - 2006 TI - Making meaningful inferences about magnitudes SP - 50-57. Sportscience. 2005;9:6-13 JF - IJSPP VL - 1 N1 - Making meaningful inferences about magnitudes N1 - 64 ID - 142 ER - TY - JOUR AU - Beneke, R. AU - Leithauser, R. M. AU - Hutler, M. PY - 2001 TI - Dependence of the maximal lactate steady state on the motor pattern of exercise SP - 192-6 N1 - Jun JF - Br J Sports Med VL - 35 IS - 3 N1 - Dependence of the maximal lactate steady state on the motor pattern of exercise N1 - 623 N1 - 11375880 Beneke, R Leithauser, R M Hutler, M England British journal of sports medicine Br J Sports Med. 2001 Jun;35(3):192-6. KW - Adolescent Exercise Tolerance Humans Lactic Acid/blood/*metabolism Linear Models Male Sports/*physiology Statistics, Nonparametric N2 - BACKGROUND: Blood lactate concentration (BLC) can be used to monitor relative exercise intensity. The highest BLC representing an equilibrium between lactate production and elimination is termed maximal lactate steady state (MLSS). MLSS is used to discriminate qualitatively between continuous exercise, which is limited by stored energy, from other types of exercise terminated because of disturbance of cellular homoeostasis. AIM: To investigate the hypothesis that MLSS intraindividually depends on the mode of exercise. METHODS: Six junior male rowers (16.5 (1.4) years, 181.7 (3.1) cm, 69.8 (3.3) kg) performed incremental and constant load tests on rowing and cycle ergometers. Measurements included BLC, sampled from the hyperaemic ear flap, heart rate, and oxygen uptake. MLSS was defined as the highest BLC that increased by no more than 1.0 mmol/l during the final 20 minutes of constant workload. RESULTS: In all subjects, MLSS was lower (p < or = 0.05) during rowing (2.7 (0.6) mmol/l) than during cycling (4.5 (1.0) mmol/l). No differences between rowing and cycling were found with respect to MLSS heart rate (169.2 (9.3) v 172.3 (6.7) beats/min), MLSS workload (178.7 (29.8) v 205.0 (20.7) W), MLSS intensity expressed as a percentage (63.3 (6.6)% v 68.6 (3.8)%) of peak workload (280.8 (15.9) v 299.2 (28.4) W) or percentage (76.4 (3.4)% v 75.1 (3.0)%) of peak oxygen uptake (60.4 (3.4) v 57.2 (8.6) ml/kg/min). CONCLUSIONS: In rowing and cycling, the MLSS but not MLSS workload and MLSS intensity intraindividually depends on the motor pattern of exercise. MLSS seems to decrease with increasing mass of the primarily engaged muscle. This indicates that task specific levels of MLSS occur at distinct levels of power output per unit of primarily engaged muscle mass. AD - Sports Medicine, Free University, Berlin, Germany. rabe94@zedat.fu-berlin.de UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11375880 ID - 90 ER - TY - JOUR AU - Beneke, R. AU - von Duvillard, S. P. PY - 1996 TI - Determination of maximal lactate steady state response in selected sports events SP - 241-6 N1 - Feb JF - Med Sci Sports Exerc VL - 28 IS - 2 N1 - Determination of maximal lactate steady state response in selected sports events N1 - 624 N1 - 8775160 Beneke, R von Duvillard, S P United states Medicine and science in sports and exercise Med Sci Sports Exerc. 1996 Feb;28(2):241-6. KW - Adult Bicycling/physiology Humans Lactic Acid/*blood Male Muscle, Skeletal/physiology Skating/physiology Sports/*physiology N2 - Maximal lactate steady state (MLSS) refers to the upper limit of blood lactate concentration indicating an equilibrium between lactate production and lactate elimination during constant workload. The aim of the present study was to investigate whether different levels of MLSS may explain different blood lactate concentration (BLC) levels at submaximal workload in the sports events of rowing, cycling, and speed skating. Eleven rowers (mean +/- SD, age 20.1 +/- 1.5 yr, height 188.7 +/- 6.2 cm, weight 82.7 +/- 8.0 kg), 16 cyclists and triathletes (age 23.6 +/- 3.0 yr, height 181.4 +/- 5.6 cm, weight 72.5 +/- 6.2 kg), and 6 speed skaters (age 23.3 +/- 6.6 yr, height 179.5 +/- 7.5 cm, weight 73.2 +/- 5.6 kg) performed an incremental load test to determine maximal workload and several submaximal 30-min constant workloads for MLSS measurement on a rowing ergometer, a cycle ergometer, and on a speed-skating track. Maximal workload was higher (P < or = 0.05) in rowing (416.8 +/- 46.2 W) than in cling (358.6 +/- 34.4 W) and speed skating (383.5 +/- 40.9 W). The level of MLSS differed (P < or = 0.001) in rowing (3.1 +/- 0.5 mmol.l-1), cycling (5.4 +/- 1.0 mmol.l-1), and in speed skating (6.6 +/- 0.9 mmol.l-1). MLSS workload was higher (P < or = 0.05) in rowing (316.2 +/- 29.9 W) and speed skating (300.5 +/- 43.8 W) than in cycling (257.8 +/- 34.6 W). No differences (P > 0.05) in MLSS workload were found between speed skating and rowing. MLSS workload intensity as related to maximal workload was independent (P > 0.05) of the sports event: 76.2% +/- 5.7% in rowing, 71.8% +/- 4.1% in cycling, and 78.1% +/- 4.4% in speed skating. Changes in MLSS do not respond with MLSS workload, the MLSS workload intensity, or with the metabolic profile of the sports event. The observed differences in MLSS and MLSS workload may correspond to the sport-specific mass of working muscle. AD - Department of Sports Medicine, Free University Berlin, Germany. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8775160 ID - 89 ER - TY - JOUR AU - Berger, N. J. AU - Tolfrey, K. AU - Williams, A. G. AU - Jones, A. M. PY - 2006 TI - Influence of continuous and interval training on oxygen uptake on-kinetics SP - 504-12 N1 - Mar JF - Med Sci Sports Exerc VL - 38 IS - 3 N1 - Influence of continuous and interval training on oxygen uptake on-kinetics N1 - 28 N1 - 16540838 Berger, Nicolas J A Tolfrey, Keith Williams, Alun G Jones, Andrew M United States Medicine and science in sports and exercise Med Sci Sports Exerc. 2006 Mar;38(3):504-12. KW - Adult *Exercise Exercise Test/methods Great Britain Humans Kinetics Male Oxygen Consumption/*physiology Physical Endurance N2 - PURPOSE: To examine the relative effectiveness of moderate-intensity continuous training and high-intensity interval training on pulmonary O2 uptake (VO2) kinetics at the onset of moderate- and severe-intensity cycle exercise in previously sedentary subjects. METHODS: Twenty-three healthy subjects (11 males; mean +/- SD age 24 +/- 5 yr; VO2peak 34.3 +/- 5.5 mL x kg(-1) x min(-1)) were assigned to one of three groups: a continuous training group that completed three to four sessions per week of 30-min duration at 60% VO2peak (LO); an interval training group that completed three to four sessions per week involving 20 x 1-min exercise bouts at 90% VO2peak separated by 1-min rest periods (HI); or a control group (CON). Before and after the 6-wk intervention period, all subjects completed a series of step exercise tests to moderate and severe work rates during which pulmonary VO2 was measured breath-by-breath. RESULTS: ANOVA revealed that continuous and interval training were similarly effective in reducing the phase II VO2 time constant during moderate (LO: from 31 +/- 8 to 23 +/- 5 s; HI: from 32 +/- 9 to 21 +/- 4 s; both P < 0.05; CON: from 30 +/- 6 to 29 +/- 7 s; NSD) and severe exercise (LO: from 35 +/- 6 to 24 +/- 7 s; HI: from 32 +/- 11 to 24 +/- 7 s; both P < 0.05; CON: from 27 +/- 7 to 25 +/- 5 s; NSD) and in reducing the amplitude of the VO2 slow component (LO: from 0.38 +/- 0.10 to 0.29 +/- 0.09 L x min(-1); HI: from 0.41 +/- 0.28 to 0.30 +/- 0.28 L x min(-1); both P < 0.05; CON: from 0.54 +/- 0.22 to 0.66 +/- 0.38 L.min; NSD). CONCLUSIONS: Six weeks of low-intensity continuous training and high-intensity interval training were similarly effective in enhancing VO2 on-kinetics following step transitions to moderate and severe exercise in previously untrained subjects. AD - Department of Exercise and Sport Science, Manchester Metropolitan University, Hassall Road, Alsager, United Kingdom. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16540838 ID - 101 ER - TY - JOUR AU - Bhambhani, Y. AU - Singh, M. PY - 1985 TI - The effects of three training intensities on VO2 max and VE/VO2 ratio SP - 44-51 N1 - Mar JF - Can J Appl Sport Sci VL - 10 IS - 1 N1 - The effects of three training intensities on VO2 max and VE/VO2 ratio N1 - 552 N1 - 3924424 Bhambhani, Y Singh, M Comparative Study Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Canada Canadian journal of applied sport sciences. Journal canadien des sciences appliquees au sport Can J Appl Sport Sci. 1985 Mar;10(1):44-51. KW - Carbon Dioxide/metabolism Exercise Test Humans Male *Oxygen Consumption Physical Education and Training/*methods Physical Fitness *Pulmonary Ventilation N2 - This study examined the effects of three training intensities on the maximum oxygen uptake (VO2 max) and ventilatory equivalents for oxygen (VE/VO2 ratio) and carbon dioxide (VE/VCO2 ratio) at submaximal and maximal workloads. Forty males, classified as high or low fit according to their relative VO2 max, were assigned to one of four subgroups: a control group that did not train; a continuous training group that trained at an oxygen uptake that was 10% above that at which the VE/VO2 ratio reached a minimum; another continuous training group that trained at an oxygen uptake that was mid-way between that at which the VE/VO2 ratio reached its minimum and maximum; and an interval training group which trained at 100% VO2 max. The work:rest intervals were one minute each. Initial fitness level and total training power output for the eight week program was equalized in each group in the two fitness categories. The results indicated that both fitness categories responded similarly to the three training intensities. The training groups showed significant but equivalent increases in the VO2 max, but no significant changes in the max VE/VO2 or max VE/VCO2 ratios. The submaximal VE/VO2 and VE/VCO2 ratios were significantly lowered, primarily as a result of a significantly lowered, primarily as a result of a significant decrease in the ventilation volume. It was concluded that continuous and interval training programs wee equally effective in improving VO2 max and submaximal ventilatory efficiency, regardless of initial fitness level, provided the total amount of work completed was equalized. Such training programs, however, were unable to modify the maximal ventilatory efficiency in either fitness category. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=3924424 ID - 103 ER - TY - JOUR AU - Billat, V. AU - Lepretre, P. M. AU - Heugas, A. M. AU - Laurence, M. H. AU - Salim, D. AU - Koralsztein, J. P. PY - 2003 TI - Training and bioenergetic characteristics in elite male and female Kenyan runners SP - 297-304; discussion 305-6 N1 - Feb JF - Med Sci Sports Exerc VL - 35 IS - 2 N1 - Training and bioenergetic characteristics in elite male and female Kenyan runners N1 - 833 N1 - 12569219 Billat, Veronique Lepretre, Pierre-Marie Heugas, Anne-Marie Laurence, Mille-Hamard Salim, Drai Koralsztein, Jean Pierre Research Support, Non-U.S. Gov't United States Medicine and science in sports and exercise Med Sci Sports Exerc. 2003 Feb;35(2):297-304; discussion 305-6. KW - Adult Female Humans Kenya Lactic Acid/blood Male Oxygen Consumption/*physiology Physical Endurance/*physiology Running/*physiology Sex Factors N2 - PURPOSE: This study compares the training characteristics and the physical profiles of top-class male and female Kenyan long-distance runners. METHOD: The subjects were 20 elite Kenyan runners: 13 men (10-km performance time: 10-km performance time of 28 min, 36 s +/- 18 s) and 7 women (32 min, 32 s +/- 65 s). The male runners were separated into high-speed training runners (HST: N = 6) and low-speed training runners (LST: N = 7) depending on whether they train at speeds equal or higher than those associated with the maximal oxygen uptake (vVO2max ). All but one woman were high-speed training runners (female HST: N = 6). Subjects performed an incremental test on a 400-m track to determine VO2max, vVO2max, and the velocity at the lactate threshold (vLT). RESULTS: Within each gender among the HST group, 10-km performance time was inversely correlated with vVO2max (rho = -0.86, P = 0.05, and rho = -0.95, P = 0.03, for men and women, respectively). HST male runners had a higher VO2max, a lower (but not significantly) fraction of vVO2max (FVO2max ) at the lactate threshold, and a higher energy cost of running (ECR). Among men, the weekly training distance at vVO2max explained 59% of the variance of vVO2max, and vVO2max explained 52% of the variance of 10-km performance time. Kenyan women had a high VO2max and FVO2max at vLT that was lower than their male HST counterparts. ECR was not significantly different between genders. CONCLUSION: The velocity at the VO2max is the main factor predicting the variance of the 10-km performance both in men and women, and high-intensity training contributes to this higher VO2max among men. AD - Faculty of Sport Science, University of Evry-Val d'Essonne, France. veronique.billat@wanadoo.fr UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12569219 ID - 52 ER - TY - JOUR AU - Billat, V. L. AU - Demarle, A. AU - Slawinski, J. AU - Paiva, M. AU - Koralsztein, J. P. PY - 2001 TI - Physical and training characteristics of top-class marathon runners SP - 2089-97 N1 - Dec JF - Med Sci Sports Exerc VL - 33 IS - 12 N1 - Physical and training characteristics of top-class marathon runners N1 - 827 N1 - 11740304 Billat, V L Demarle, A Slawinski, J Paiva, M Koralsztein, J P Comparative Study United States Medicine and science in sports and exercise Med Sci Sports Exerc. 2001 Dec;33(12):2089-97. KW - Body Weight Energy Metabolism/physiology Female Humans Lactic Acid/blood Male Oxygen Consumption/physiology Physical Education and Training/*methods Physical Fitness/*physiology Running/*physiology Sex Factors *Task Performance and Analysis Time Factors N2 - PURPOSE: This study compares the physical and training characteristics of top-class marathon runners (TC), i.e., runners having a personal best of less than 2 h 11 min for males and 2 h 32 min for females, respectively, versus high-level (HL) (< 2 h 16 min and < 2 h 38 min). METHODS: Twenty marathon runners (five TC and HL in each gender) ran 10 km at their best marathon performance velocity (vMarathon) on a level road. This velocity was the target velocity for the Olympic trials they performed 8 wk later. After a rest of 6 min, they ran an all-out 1000-m run to determine the peak oxygen consumption on flat road (.VO(2peak)). RESULTS: Marathon performance time (MPT) was inversely correlated with .VO(2peak). (r = -0.73, P < 0.01) and predicted 59% of the variance of MPT. Moreover, TC male marathon runners were less economical because their energy cost of running (Cr) at marathon velocity was significantly higher than that of their counterparts (212 +/- 17 vs 195 +/- 14 mL.km(-1).kg(-1), P = 0.03). For females, no difference was observed for the energetic characteristics between TC and HL marathon runners. However, the velocity reached during the 1000-m run performed after the 10-km run at vMarathon was highly correlated with MPT (r = -0.85, P < 0.001). Concerning training differences, independent of the gender, TC marathon runners trained for more total kilometers per week and at a higher velocity (velocity over 3000 m and 10,000 m). CONCLUSION: The high energy output seems to be the discriminating factor for top-class male marathon runners who trained at higher relative intensities. AD - Faculty of Sport Science, University of Lille 2, Lille, France. veronique.billat@wanadoo.fr UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11740304 ID - 53 ER - TY - JOUR AU - Billat, V. L. AU - Flechet, B. AU - Petit, B. AU - Muriaux, G. AU - Koralsztein, J. P. PY - 1999 TI - Interval training at VO2max: effects on aerobic performance and overtraining markers SP - 156-63 N1 - Jan JF - Med Sci Sports Exerc VL - 31 IS - 1 N1 - Interval training at VO2max: effects on aerobic performance and overtraining markers N1 - 63 N1 - 9927024 Billat, V L Flechet, B Petit, B Muriaux, G Koralsztein, J P United states Medicine and science in sports and exercise Med Sci Sports Exerc. 1999 Jan;31(1):156-63. KW - Adult Heart Rate Humans Lactic Acid/blood Male Norepinephrine/blood *Oxygen Consumption Physical Endurance/*physiology Running/*physiology N2 - PURPOSE: Between inefficient training and overtraining, an appropriate training stimulus (in terms of intensity and duration) has to be determined in accordance with individual capacities. Interval training at the minimal velocity associated with VO2max (vVO2max) allows an athlete to run for as long as possible at VO2max. Nevertheless, we don't know the influence of a defined increase in training volume at vVO2max on aerobic performance, noradrenaline, and heart rate. METHODS: Eight subjects performed 4 wk of normal training (NT) with one session per week at vVO2max, i.e., five repetitions run at 50% of the time limit at vVO2max, with recovery of the same duration at 60% vVO2max. They then performed 4 wk of overload training (OT) with three interval training sessions at vVO2max. RESULTS: Normal training significantly improved their velocity associated with VO2max (20.5+/-0.7 vs 21.1+/-0.8 km x h(-1), P = 0.02). As a result of improved running economy (50.6+/-3.5 vs 47.5+/-2.4 mL x min(-1) x kg(-1), P = 0.02), VO2max was not significantly different (71.6+/-4.8 vs 72.7+/-4.8 mL x min(-1) x kg(-1)). Time to exhaustion at vVO2max was not significantly different (301+/-56 vs 283+/-41 s) as was performance (i.e., distance limit run at vVO2max: 2052.2+/-331 vs 1986.2+/-252.9 m). Heart rate at 14 km x h(-1) decreased significantly after NT (162+/-16 vs 155+/-18 bpm, P < 0.01). Lactate threshold remained the same after normal training (84.1+/-4.8% vVO2max). Overload training changed neither the performance nor the factors concerning performance. However, the submaximal heart rate measured at 14 km x h(-1) decreased after overload training (155+/-18 vs 150+/-15 bpm). The maximal heart rate was not significantly different after NT and OT (199+/-9.5, 198+/-11, 194+/-10.4, P = 0.1). Resting plasma norepinephrine (veinous blood sample measured by high pressure liquid chromatography), was unchanged (2.6 vs 2.4 nm x L(-1), P = 0.8). However, plasma norepinephrine measured at the end of the vVO2max test increased significantly (11.1 vs 26.0 nm x L(-1), P = 0.002). CONCLUSION: Performance and aerobic factors associated with the performance were not altered by the 4 wk of intensive training at vVO2max despite the increase of plasma noradrenaline. AD - Sport Science Laboratory, Universite Lille 2, Centre de Medicine du Sport C.C.A.S., Paris, France. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9927024 ID - 92 ER - TY - JOUR AU - Bossuyt, P. M. AU - Reitsma, J. B. AU - Bruns, D. E. AU - Gatsonis, C. A. AU - Glasziou, P. P. AU - Irwig, L. M. AU - Lijmer, J. G. AU - Moher, D. AU - Rennie, D. AU - de Vet, H. C. PY - 2003 TI - Towards complete and accurate reporting of studies of diagnostic accuracy: the STARD initiative SP - 41-4 JF - BMJ VL - 326 N1 - Towards complete and accurate reporting of studies of diagnostic accuracy: the STARD initiative N1 - 40 ID - 136 ER - TY - JOUR AU - Bossuyt, P. M. AU - Reitsma, J. B. AU - Bruns, D. E. AU - Gatsonis, C. A. AU - Glasziou, P. P. AU - Irwig, L. M. AU - Moher, D. AU - Rennie, D. AU - de Vet, H. C. W. AU - Lijmer, J. G. PY - 2003 TI - The STARD statement for reporting studies of diagnostic accuracy: explanation and elaboration SP - 7-18 JF - Clin Chem VL - 49 N1 - The STARD statement for reporting studies of diagnostic accuracy: explanation and elaboration N1 - 57 ID - 137 ER - TY - JOUR AU - Brigelius-Flohe, R. PY - 2009 TI - Commentary: oxidative stress reconsidered SP - 161-163 JF - Genes and Nutrition VL - 4 N1 - Commentary: oxidative stress reconsidered N1 - 1118 ID - 75 ER - TY - JOUR AU - Catalucci, D. AU - Latronico, M. V. AU - Ellingsen, O. AU - Condorelli, G. PY - 2008 TI - Physiological myocardial hypertrophy: how and why? SP - 312-24 JF - Front Biosci VL - 13 N1 - Physiological myocardial hypertrophy: how and why? N1 - 1046 N1 - 17981549 Catalucci, Daniele Latronico, Michael V G Ellingsen, Oyvind Condorelli, Gianluigi R0 HL078797-01A1/HL/NHLBI NIH HHS/United States Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't Review United States Frontiers in bioscience : a journal and virtual library Front Biosci. 2008 Jan 1;13:312-24. KW - 1-Phosphatidylinositol 3-Kinase/metabolism Animals Cell Proliferation Female Humans Hypertrophy Insulin-Like Growth Factor I/metabolism Male Models, Biological Myocardium/*pathology Neovascularization, Pathologic Pregnancy Proto-Oncogene Proteins c-akt/metabolism Receptors, Adrenergic/metabolism Signal Transduction N2 - Cardiac hypertrophy is defined by augmentation of ventricular mass as a result of increased cardiomyocyte size, and is the adaptive response of the heart to enhanced hemodynamic loads due to either physiological stimuli (post-natal developmental growth, training, and pregnancy) or pathological states (such as hypertension, valvular insufficiency, etc). The mechanisms leading to hypertrophy during pathological and physiological states are distinct but, in general, evidence indicates that hypertrophy results from the interaction of mechanical forces and neurohormonal factors. Hemodynamic overload creates a mechanical burden on the heart and results in stretch of the myocyte and induction of gene expression of cardiac growth factors. Insulin-like growth factor 1 (IGF1) has recently been shown to be the most important cardiac growth factor involved in physiological hypertrophy. In this review, IGF1 and the pathways it triggers will be discussed. AD - Department of Medicine, Division of Cardiology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613, USA. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=17981549 ID - 70 ER - TY - JOUR AU - Chakravarthy, M. V. AU - Booth, F. W. PY - 2004 TI - Eating, exercise, and "thrifty" genotypes: connecting the dots toward an evolutionary understanding of modern chronic diseases SP - 3-10 N1 - Jan JF - J Appl Physiol VL - 96 IS - 1 N1 - Eating, exercise, and "thrifty" genotypes: connecting the dots toward an evolutionary understanding of modern chronic diseases N1 - 822 N1 - 14660491 Chakravarthy, Manu V Booth, Frank W KW - *Chronic Disease Energy Metabolism/genetics *Evolution Feeding Behavior/*physiology Genotype Humans Physical Exertion/*physiology Starvation/*genetics/metabolism N2 - Survival of Homo sapiens during evolution was dependent on the procurement of food, which in turn was dependent on physical activity. However, food supply was never consistent. Thus it is contended that the ancient hunter-gatherer had cycles of feast and famine, punctuated with obligate periods of physical activity and rest. Hence, gene selection in the Late-Paleolithic era was probably influenced by physical activity and rest. To ensure survival during periods of famine, certain genes evolved to regulate efficient intake and utilization of fuel stores. Such genes were termed "thrifty genes" in 1962. Furthermore, convincing evidence shows that this ancient genome has remained essentially unchanged over the past 10,000 years and certainly not changed in the past 40-100 years. Although the absolute caloric intake of modern-day humans is likely lower compared with our hunter-gatherer ancestors, it is nevertheless in positive caloric balance in the majority of the US adult population mainly due to the increased sedentary lifestyle in present society. We contend that the combination of continuous food abundance and physical inactivity eliminates the evolutionarily programmed biochemical cycles emanating from feast-famine and physical activity-rest cycles, which in turn abrogates the cycling of certain metabolic processes, ultimately resulting in metabolic derangements such as obesity and Type 2 diabetes. In this context, we postulate that perhaps a crucial mechanism to break the stall of the metabolic processes would be via exercise through the regulation of "physical activity genes," some of which may also be potential candidates for the "thrifty genes" of our hunter-gatherer ancestors. Therefore, the identification of such "thrifty gene" candidates would help provide insight into the pathogenetic processes of the numerous physical inactivity-mediated disorders. AD - Division of Endocrinology, Metabolism and Lipid Research, Department of Internal Medicine, Washington University School of Medicine, St Louis 63110, USA. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=14660491 ID - 56 ER - TY - JOUR AU - Chow, J. Y. AU - Davids, K. AU - Button, C. AU - Shuttleworth, R. AU - Renshaw, I. AU - Araujo, D. PY - 2007 TI - The role of nonlinear pedagogy in physical education SP - 251-278 JF - Review of Educational Research VL - 77 N1 - The role of nonlinear pedagogy in physical education ID - 7 ER - TY - JOUR AU - Christensen, E. H. PY - 1960 TI - [Interval work and interval training.] SP - 345-56 JF - Int Z Angew Physiol VL - 18 N1 - [Interval work and interval training.] N1 - 541 N1 - 13810077 Christensen, e h Not Available Internationale Zeitschrift fur angewandte Physiologie, einschliesslich Arbeitsphysiologie Int Z Angew Physiol. 1960;18:345-56. KW - *Physical Education and Training *Physical Exertion UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=13810077 ID - 121 ER - TY - JOUR AU - Christensen, E. H. AU - Hedman, R. AU - Saltin, B. PY - 1960 TI - Intermittant and continuous running SP - 269-286 JF - Acta Physiolologica Scandinavica VL - 50 N1 - Intermittant and continuous running N1 - 843 ID - 120 ER - TY - BOOK AU - Cohen, J. PY - 1988 BT - Statistical Power Analysis for the Behavioral Sciences CY - Hillsdale, NJ PB - Lawrence Erlbaum SP - 567 N1 - Statistical Power Analysis for the Behavioral Sciences N1 - 23 N1 - 2nd part KW - stats, design, effect size, power ID - 144 ER - TY - JOUR AU - Cunningham, D. A. AU - McCrimmon, D. AU - Vlach, L. F. PY - 1979 TI - Cardiovascular response to interval and continuous training in women SP - 187-97 N1 - Jul 2 JF - Eur J Appl Physiol Occup Physiol VL - 41 IS - 3 N1 - Cardiovascular response to interval and continuous training in women N1 - 500 N1 - 488084 Cunningham, D A McCrimmon, D Vlach, L F Germany, west European journal of applied physiology and occupational physiology Eur J Appl Physiol Occup Physiol. 1979 Jul 2;41(3):187-97. KW - Adolescent Adult *Body Weight Cardiac Output Female Heart/*physiology Hematocrit Humans Lactates/blood Oxygen Consumption *Physical Education and Training *Physical Exertion Time Factors N2 - Three groups of five women (age = 18--25 years) participated in a 12-week training program. Cardiovascular responses up to 85% VO2 max to interval (ITG) and continuous (CTG) training were studied in two groups, before training and after 4, 8, and 12 weeks of training four times per week. A control group was assessed before and after 6 and 12 weeks. Both exercise groups demonstrated significant increases in Cao2--Cvo2 after 8 weeks with only slight further increases after 12 weeks (CTG = 8.9%, ITG = 20.0% at 85% VO2 max). No significant changes were noted in either group in SV (+ 5 ml ITG, + 9 ml CTG) or in their Qc. These results indicated that, in response to high intensity training, women may demonstrate similar cardiovascular adaptations to training as have been observed for men. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=488084 ID - 111 ER - TY - JOUR AU - Curran-Everett, D. AU - Benos, D. J. PY - 2004 TI - Guidelines for reporting statistics in journals published by the American Physiological Society SP - 457-459 JF - Journal of Applied Physiology VL - 97 N1 - Guidelines for reporting statistics in journals published by the American Physiological Society N1 - 7 ID - 131 ER - TY - JOUR AU - Daniels, J. AU - Scardina, N. PY - 1984 TI - Interval training and performance SP - 327-34 N1 - Jul-Aug JF - Sports Med VL - 1 IS - 4 N1 - Interval training and performance N1 - 844 N1 - 6390607 Daniels, J Scardina, N Review New zealand Sports medicine (Auckland, N.Z.) Sports Med. 1984 Jul-Aug;1(4):327-34. KW - Aerobiosis Humans Oxygen Consumption *Physical Education and Training Physical Exertion Rest Running Swimming N2 - Researchers, coaches and athletes have a variety of concepts of interval training, the only point of agreement being that interval training involves alternating bouts of exercise and recovery. The idea that interval training can be identified by a specific intensity, duration, or number of exercise bouts or by the amount or type of recovery between bouts of exercise is not valid. Rather, interval training has come to mean any type of intermittent training which, with manipulation of the number, intensity and duration of work bouts and amounts of recovery, is used to produce a particular type of stress on the body. There is general agreement that rather specific guidelines are available which determine the amount and intensity of work and the amount of rest necessary to produce specific results, and it is suggested that types of training be identified based on the specific characteristics of each particular type of training rather than placing all types of intermittent training in an all-inclusive category called 'interval training'. Further efforts should be made to continue investigations which help determine how much, how often and for whom the various types of intermittent training are beneficial. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=6390607 ID - 122 ER - TY - JOUR AU - Daussin, F. N. AU - Ponsot, E. AU - Dufour, S. P. AU - Lonsdorfer-Wolf, E. AU - Doutreleau, S. AU - Geny, B. AU - Piquard, F. AU - Richard, R. PY - 2007 TI - Improvement of VO2max by cardiac output and oxygen extraction adaptation during intermittent versus continuous endurance training SP - 377-83 N1 - Oct JF - Eur J Appl Physiol VL - 101 IS - 3 N1 - Improvement of VO2max by cardiac output and oxygen extraction adaptation during intermittent versus continuous endurance training N1 - 688 N1 - 17661072 Daussin, Frederic N Ponsot, Elodie Dufour, Stephane P Lonsdorfer-Wolf, Evelyne Doutreleau, Stephane Geny, Bernard Piquard, Francois Richard, Ruddy Research Support, Non-U.S. Gov't Germany European journal of applied physiology Eur J Appl Physiol. 2007 Oct;101(3):377-83. Epub 2007 Jul 28. KW - Adaptation, Physiological Adult Cardiac Output/*physiology *Exercise Female Humans Male Middle Aged Oxygen/*metabolism Oxygen Consumption/*physiology Physical Endurance/*physiology N2 - Improvement of exercise capacity by continuous (CT) versus interval training (IT) remains debated. We tested the hypothesis that CT and IT might improve peripheral and/or central adaptations, respectively, by randomly assigning 10 healthy subjects to two periods of 24 trainings sessions over 8 weeks in a cross-over design, separated by 12 weeks of detraining. Maximal oxygen uptake (VO2max), cardiac output (Qmax) and maximal arteriovenous oxygen difference (Da-vO2max) were obtained during an exhaustive incremental test before and after each training period. VO2max and Qmax increased only after IT (from 26.3 +/- 1.6 to 35.2 +/- 3.8 ml min(-1) kg(-1) and from 17.5 +/- 1.3 to 19.5 +/- 1.8 l min(-1), respectively; P < 0.01). Da-vO2max increased after both protocols (from 11.0 +/- 0.8 to 12.7 +/- 1.0; P < 0.01 and from 11.0 +/- 0.8 to 12.1 +/- 1.0 ml 100 ml(-1), P < 0.05 in CT and IT, respectively). At submaximal intensity a significant rightward shift of the Q/Da-vO2 relationship appeared only after CT. These results suggest that in isoenergetic training, central and peripheral adaptations in oxygen transport and utilization are training-modality dependant. IT improves both central and peripheral components of Da-vO2max whereas CT is mainly associated with greater oxygen extraction. AD - CHRU of Strasbourg, Physiology and Functional Explorations Department, Civil Hospital, BP 426, 67091, Strasbourg, France. fredericdaussin@wanadoo.fr UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=17661072 ID - 128 ER - TY - JOUR AU - Daussin, F. N. AU - Zoll, J. AU - Dufour, S. P. AU - Ponsot, E. AU - Lonsdorfer-Wolf, E. AU - Doutreleau, S. AU - Mettauer, B. AU - Piquard, F. AU - Geny, B. AU - Richard, R. PY - 2008 TI - Effect of interval versus continuous training on cardiorespiratory and mitochondrial functions: relationship to aerobic performance improvements in sedentary subjects SP - R264-72 N1 - Jul JF - Am J Physiol Regul Integr Comp Physiol VL - 295 IS - 1 N1 - Effect of interval versus continuous training on cardiorespiratory and mitochondrial functions: relationship to aerobic performance improvements in sedentary subjects N1 - 308 N1 - 18417645 Daussin, Frederic N Zoll, Joffrey Dufour, Stephane P Ponsot, Elodie Lonsdorfer-Wolf, Evelyne Doutreleau, Stephane Mettauer, Bertrand Piquard, Francois Geny, Bernard Richard, Ruddy Randomized Controlled Trial Research Support, Non-U.S. Gov't United States American journal of physiology. Regulatory, integrative and comparative physiology Am J Physiol Regul Integr Comp Physiol. 2008 Jul;295(1):R264-72. Epub 2008 Apr 16. KW - Adaptation, Physiological Adult Capillaries Cross-Over Studies Exercise/*physiology Female Heart Rate/*physiology Humans Male Middle Aged Mitochondria, Muscle/*metabolism Muscle, Skeletal/blood supply *Respiration Running N2 - The goal of the study was to determine the effects of continuous (CT) vs. intermittent (IT) training yielding identical mechanical work and training duration on skeletal muscle and cardiorespiratory adaptations in sedentary subjects. Eleven subjects (6 men and 5 women, 45 +/- 3 years) were randomly assigned to either of the two 8-wk training programs in a cross-over design, separated by 12 wk of detraining. Maximal oxygen uptake (Vo2max) increased after both trainings (9% with CT vs. 15% with IT), whereas only IT was associated with faster Vo2 kinetics (tau: 68.0 +/- 1.6 vs. 54.9 +/- 0.7 s, P < 0.05) measured during a test to exhaustion (TTE) and with improvements in maximal cardiac output (Qmax, from 18.1 +/- 1.1 to 20.1 +/- 1.2 l/min; P < 0.01). Skeletal muscle mitochondrial oxidative capacities (Vmax) were only increased after IT (3.3 +/- 0.4 before and 4.5 +/- 0.6 micromol O2 x min(-1) x g dw(-1) after training; P < 0.05), whereas capillary density increased after both trainings, with a two-fold higher enhancement after CT (+21 +/- 1% for IT and +40 +/- 3% after CT, P < 0.05). The gain of Vmax was correlated with the gain of TTE and the gain of Vo2max with IT. The gain of Qmax was also correlated with the gain of VO2max. These results suggest that fluctuations of workload and oxygen uptake during training sessions, rather than exercise duration or global energy expenditure, are key factors in improving muscle oxidative capacities. In an integrative view, IT seems optimal in maximizing both peripheral muscle and central cardiorespiratory adaptations, permitting significant functional improvement. These data support the symmorphosis concept in sedentary subjects. AD - CHRU of Strasbourg, Physiology and Functional Explorations Department, Civil Hospital, Strasbourg, France. fredericdaussin@wanadoo.fr UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=18417645 ID - 98 ER - TY - JOUR AU - Daussin, F. N. AU - Zoll, J. AU - Ponsot, E. AU - Dufour, S. P. AU - Doutreleau, S. AU - Lonsdorfer, E. AU - Ventura-Clapier, R. AU - Mettauer, B. AU - Piquard, F. AU - Geny, B. AU - Richard, R. PY - 2008 TI - Training at high exercise intensity promotes qualitative adaptations of mitochondrial function in human skeletal muscle SP - 1436-41 N1 - May JF - J Appl Physiol VL - 104 IS - 5 N1 - Training at high exercise intensity promotes qualitative adaptations of mitochondrial function in human skeletal muscle N1 - 116 N1 - 18292295 Daussin, Frederic N Zoll, Joffrey Ponsot, Elodie Dufour, Stephane P Doutreleau, Stephane Lonsdorfer, Evelyne Ventura-Clapier, Renee Mettauer, Bertrand Piquard, Francois Geny, Bernard Richard, Ruddy Research Support, Non-U.S. Gov't United States Journal of applied physiology (Bethesda, Md. : 1985) J Appl Physiol. 2008 May;104(5):1436-41. Epub 2008 Feb 21. KW - Adaptation, Physiological/*physiology Adult Carbohydrate Metabolism/physiology Cross-Sectional Studies Electron Transport/physiology Exercise/*physiology Fatty Acids/metabolism Female Humans Kinetics Male Mitochondria, Muscle/*physiology Muscle, Skeletal/*physiology Oxygen Consumption/physiology Phosphorylation Physical Fitness/*physiology Pulmonary Gas Exchange/physiology Sports/physiology N2 - This study explored mitochondrial capacities to oxidize carbohydrate and fatty acids and functional optimization of mitochondrial respiratory chain complexes in athletes who regularly train at high exercise intensity (ATH, n = 7) compared with sedentary (SED, n = 7). Peak O(2) uptake (Vo(2max)) was measured, and muscle biopsies of vastus lateralis were collected. Maximal O(2) uptake of saponin-skinned myofibers was evaluated with several metabolic substrates [glutamate-malate (V(GM)), pyruvate (V(Pyr)), palmitoyl carnitine (V(PC))], and the activity of the mitochondrial respiratory complexes II and IV were assessed using succinate (V(s)) and N,N,N',N'-tetramethyl-p-phenylenediamine dihydrochloride (V(TMPD)), respectively. Vo(2max) was higher in ATH than in SED (57.8 +/- 2.2 vs. 31.4 +/- 1.3 ml.min(-1).kg(-1), P < 0.001). V(GM) was higher in ATH than in SED (8.6 +/- 0.5 vs. 3.3 +/- 0.3 micromol O(2).min(-1).g dry wt(-1), P < 0.001). V(Pyr) was higher in ATH than in SED (8.7 +/- 1.0 vs. 5.5 +/- 0.2 micromol O(2).min(-1).g dry wt(-1), P < 0.05), whereas V(PC) was not significantly different (5.3 +/- 0.9 vs. 4.4 +/- 0.5 micromol O(2).min(-1).g dry wt(-1)). V(S) was higher in ATH than in SED (11.0 +/- 0.6 vs. 6.0 +/- 0.3 micromol O(2).min(-1).g dry wt(-1), P < 0.001), as well as V(TMPD) (20.1 +/- 1.0 vs. 16.2 +/- 3.4 micromol O(2).min(-1).g dry wt(-1), P < 0.05). The ratios V(S)/V(GM) (1.3 +/- 0.1 vs. 2.0 +/- 0.1, P < 0.001) and V(TMPD)/V(GM) (2.4 +/- 1.0 vs. 5.2 +/- 1.8, P < 0.01) were lower in ATH than in SED. In conclusion, comparison of ATH vs. SED subjects suggests that regular endurance training at high intensity promotes the enhancement of maximal mitochondrial capacities to oxidize carbohydrate rather than fatty acid and induce specific adaptations of the mitochondrial respiratory chain at the level of complex I. AD - Service de Physiologie et d'Explorations Fonctionnelles, Hopital Civil, 1 Place de l'Hopital, F-67091 Strasbourg Cedex, France. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=18292295 ID - 97 ER - TY - JOUR AU - Diaz, F. AU - Moraes, C. T. PY - 2008 TI - Mitochondrial biogenesis and turnover SP - 24-35 N1 - Jul JF - Cell Calcium VL - 44 IS - 1 N1 - Mitochondrial biogenesis and turnover N1 - 1053 N1 - 18395251 Diaz, Francisca Moraes, Carlos T Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't Review Scotland Cell calcium Cell Calcium. 2008 Jul;44(1):24-35. Epub 2008 Apr 18. KW - Animals Calcium Signaling/physiology Cell Cycle Cell Respiration/physiology *DNA, Mitochondrial/biosynthesis/chemistry/genetics Focal Adhesion Kinase 2/physiology Humans Mitochondria/*physiology Mitochondrial Membranes/chemistry/*metabolism Mitochondrial Myopathies/etiology/physiopathology Mitochondrial Proteins/genetics/*metabolism N2 - Mitochondrial biogenesis is a complex process involving the coordinated expression of mitochondrial and nuclear genes, the import of the products of the latter into the organelle and turnover. The mechanisms associated with these events have been intensively studied in the last 20 years and our understanding of their details is much improved. Mitochondrial biogenesis requires the participation of calcium signaling that activates a series of calcium-dependent protein kinases that in turn activate transcription factors and coactivators such as PGC-1alpha that regulates the expression of genes coding for mitochondrial components. In addition, mitochondrial biogenesis involves the balance of mitochondrial fission-fusion. Mitochondrial malfunction or defects in any of the many pathways involved in mitochondrial biogenesis can lead to degenerative diseases and possibly play an important part in aging. AD - Department of Neurology, University of Miami, Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA. f.diaz2@miami.edu UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=18395251 ID - 66 ER - TY - JOUR AU - Eddy, D. O. AU - Sparks, K. L. AU - Adelizi, D. A. PY - 1977 TI - The effects of continuous and interval training in women and men SP - 83-92 N1 - Sep 16 JF - Eur J Appl Physiol Occup Physiol VL - 37 IS - 2 N1 - The effects of continuous and interval training in women and men N1 - 89 N1 - 902658 Eddy, D O Sparks, K L Adelizi, D A Germany, west European journal of applied physiology and occupational physiology Eur J Appl Physiol Occup Physiol. 1977 Sep 16;37(2):83-92. KW - Adult Female Heart Rate Humans Lactates/blood Male Oxygen Consumption Physical Education and Training/*methods Physical Endurance *Physical Fitness UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=902658 ID - 110 ER - TY - JOUR AU - Edge, J. AU - Bishop, D. AU - Goodman, C. PY - 2006 TI - The effects of training intensity on muscle buffer capacity in females SP - 97-105 N1 - Jan JF - Eur J Appl Physiol VL - 96 IS - 1 N1 - The effects of training intensity on muscle buffer capacity in females N1 - 863 N1 - 16283370 Edge, Johann Bishop, David Goodman, Carmel Germany European journal of applied physiology Eur J Appl Physiol. 2006 Jan;96(1):97-105. Epub 2005 Nov 10. KW - Adolescent Adult Buffers Female Humans Hydrogen-Ion Concentration Muscle, Skeletal/*metabolism/*physiology Oxygen Consumption Physical Fitness/*physiology Pulmonary Gas Exchange N2 - We examined changes in muscle buffer capacity (beta m(in vitro)), VO2peak and the lactate threshold (LT) after 5 weeks of high-intensity interval training (INT) above the LT or moderate-intensity continuous training (CON) just below the LT. Prior to and immediately after training, 16 female subjects performed a graded exercise test to determine VO2peak and the LT, followed 2 days later by a resting muscle biopsy from the vastus lateralis muscle to determine beta m(in vitro). Following baseline testing, the subjects were randomly placed into the INT (n=8) or CON training group (n=8). Subjects then performed 5 weeks of cycle training (3 days per week), performing either high-intensity INT (6-10x2 min at 120-140% LT with 1 min rest) or moderate-intensity CON (80-95% LT) training. Total training volume was matched between the two groups. After the training period, both groups had significant improvements in VO2peak (12-14%; P<0.05) and the LT (7-10%; P<0.05), with no significant differences between groups. The INT group, however, had significantly greater improvements in beta m(in vitro) (25%; 123+/-5-153+/-7 micromol H+ x g muscle dm(-1) x pH(-1); P<0.05) than the CON group (2%; 130+/-12-133+/-7 micromol H+ x g muscle dm(-1) x pH(-1), P>0.05). Our results show that when matched for training volume, high-intensity interval training above the LT results in similar improvements in VO2peak and the LT, but greater improvements in beta m(in vitro) than moderate-intensity continuous training below the LT. This suggests that training intensity is an important determinant of changes to beta m(in vitro). AD - Team Sport Research Group, School of Human Movement and Exercise Science, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16283370 ID - 100 ER - TY - JOUR AU - Ekblom, B PY - 2009 TI - Counterpoint: maximal oxygen uptake is not limited by a central nervous system governor SP - 339-341 JF - Journal of Applied Physiology VL - 106 N1 - Counterpoint: maximal oxygen uptake is not limited by a central nervous system governor ID - 2 ER - TY - JOUR AU - Ekblom, B. T. PY - 2009 TI - Last word on Point:Counterpoint: maximal oxygen uptake is/is not limited by a central nervous system governor SP - 348 JF - Journal of Applied Physiology VL - 106 N1 - Last word on Point:Counterpoint: maximal oxygen uptake is/is not limited by a central nervous system governor ID - 18 ER - TY - BOOK AU - Enoka, R M PY - 2008 BT - Neuromechanics of Human Movement CY - Champaign, IL PB - Human Kinetics VL - 4th N1 - Neuromechanics of Human Movement ID - 21 ER - TY - JOUR AU - Enoka, R. M. AU - Stuart, D. G. PY - 1992 TI - Neurobiology of muscle fatigue SP - 1631-1648 JF - Journal of Applied Physiology VL - 72 N1 - Neurobiology of muscle fatigue ID - 4 ER - TY - JOUR AU - Esteve-Lanao, J. AU - Foster, C. AU - Seiler, S. AU - Lucia, A. PY - 2007 TI - Impact of training intensity distribution on performance in endurance athletes SP - 943-9 N1 - Aug JF - J Strength Cond Res VL - 21 IS - 3 N1 - Impact of training intensity distribution on performance in endurance athletes N1 - 949 N1 - 17685689 Esteve-Lanao, Jonathan Foster, Carl Seiler, Stephen Lucia, Alejandro Comparative Study Randomized Controlled Trial United States Journal of strength and conditioning research / National Strength & Conditioning Association J Strength Cond Res. 2007 Aug;21(3):943-9. KW - Adult Competitive Behavior Heart Rate/physiology Humans Lactates/blood Male Muscle Strength/physiology Oxygen Consumption/physiology Physical Education and Training/*methods Physical Endurance/*physiology Running/*physiology Statistics, Nonparametric N2 - The purpose of this study was to compare the effect of 2 training programs differing in the relative contribution of training volume, clearly below vs. within the lactate threshold/maximal lactate steady state region on performance in endurance runners. Twelve subelite endurance runners (who are specialists in track events, mostly the 5,000-m race usually held during spring-summer months and who also participate in cross-country races [9-12 km] during fall and winter months) were randomly assigned to a training program emphasizing low-intensity (subthreshold) (Z1) or moderately high-intensity (between thresholds) (Z2) training intensities. At the start of the study, the subjects performed a maximal exercise test to determine ventilatory (VT) and respiratory compensation thresholds (RCT), which allowed training to be controlled based on heart rate during each training session over a 5-month training period. Subjects performed a simulated 10.4-km cross-country race before and after the training period. Training was quantified based on the cumulative time spent in 3 intensity zones: zone 1 (low intensity; RCT). The contribution of total training time spent in zones 1 and 2 was controlled to have relatively more low-intensity training in Z1 (80.5 +/- 1.8% and 11.8 +/- 2.0%, respectively) than in Z2 (66.8 +/- 1.1% and 24.7 +/- 1.5%, respectively), whereas the contribution of high-intensity (zone 3) training was similar (8.3 +/- 0.7% [Z1] and 8.5 +/- 1.0% [Z2]). The magnitude of the improvement in running performance was significantly greater (p = 0.03) in Z1 (-157 +/- 13 seconds) than in Z2 (-121.5 +/- 7.1 seconds). These results provide experimental evidence supporting the value of a relatively large percentage of low-intensity training over a long period ( approximately 5 months), provided that the contribution of high-intensity training remains sufficient. AD - Exercise Physiology Laboratory, European University of Madrid, Madrid, Spain. jonathan.esteve@uem.es UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=17685689 ID - 37 ER - TY - JOUR AU - Esteve-Lanao, J. AU - San Juan, A. F. AU - Earnest, C. P. AU - Foster, C. AU - Lucia, A. PY - 2005 TI - How do endurance runners actually train? Relationship with competition performance SP - 496-504 N1 - Mar JF - Med Sci Sports Exerc VL - 37 IS - 3 N1 - How do endurance runners actually train? Relationship with competition performance N1 - 633 N1 - 15741850 Esteve-Lanao, Jonathan San Juan, Alejandro F Earnest, Conrad P Foster, Carl Lucia, Alejandro Clinical Trial Comparative Study United States Medicine and science in sports and exercise Med Sci Sports Exerc. 2005 Mar;37(3):496-504. KW - Adaptation, Physiological/physiology Adult Competitive Behavior/physiology Heart Rate/physiology Humans Oxygen Consumption/physiology Physical Education and Training/*methods Physical Endurance/*physiology Running/*physiology *Task Performance and Analysis N2 - PURPOSE: To quantify the relationship between total training load and running performance during the most important competitions of the season (national cross-country championships, 4.175- and 10.130-km races). METHODS: Eight well-trained, subelite endurance runners (age (mean+/-SD): 23+/-2 yr; VO2max: 70.0+/-7.3 mL.kg.min) performed a maximal cardiorespiratory exercise test before the training period to determine ventilatory threshold (VT) and respiratory compensation threshold (RCT). Heart rate was continuously recorded using telemetry during each training session over a 6-month macrocycle, designed to achieve peak performance during the aforementioned cross-country races, lasting from late August to the time that these races were held, that is, mid-February. This allowed us to quantify the total cumulative time spent in three intensity zones calculated as zone 1 (low intensity, lower than the VT); zone 2 (moderate intensity, between VT and RCT); and zone 3 (high intensity, above the RCT). RESULTS: Total training time in zone 1 (4581+/-979 min) was significantly higher (P<0.001) than that accumulated in zones 2 (1354+/-583 min) and 3 (487+/-154 min). Total time in zone 2 was significantly higher than time in zone 3 (P<0.05). A correlation coefficient of r=-0.79 (P=0.06) and r=-0.97 (P=0.008) was found between the total training time spent in zone 1 and performance time during the short and long cross-country races, respectively. CONCLUSIONS: Our findings suggest that total training time spent at low intensities might be associated with improved performance during highly intense endurance events, especially if the event duration is approximately 35 min. Interventional studies (i.e., improving or reducing training time in zone 1) are needed to corroborate our findings and to elucidate the physiological mechanisms behind them. AD - Exercise Physiology Laboratory, European University of Madrid, SPAIN. jonathan.esteve@fme.afd.uem.es UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15741850 ID - 88 ER - TY - JOUR AU - Evertsen, F. AU - Medbo, J. I. AU - Bonen, A. PY - 2001 TI - Effect of training intensity on muscle lactate transporters and lactate threshold of cross-country skiers SP - 195-205 N1 - Oct JF - Acta Physiol Scand VL - 173 IS - 2 N1 - Effect of training intensity on muscle lactate transporters and lactate threshold of cross-country skiers N1 - 908 N1 - 11683677 Evertsen, F Medbo, J I Bonen, A Research Support, Non-U.S. Gov't England Acta physiologica Scandinavica Acta Physiol Scand. 2001 Oct;173(2):195-205. KW - Adolescent Adult Exercise/*physiology Exercise Test Female Humans Lactic Acid/*blood Male Monocarboxylic Acid Transporters/*metabolism Muscle Fibers, Skeletal/metabolism *Muscle Proteins Muscle, Skeletal/cytology/*physiology Oxygen Consumption/physiology Skiing/*physiology Symporters/metabolism N2 - The training intensity may affect the monocarboxylate transporters MCT1 and MCT4 in skeletal muscle. Therefore, 20 elite cross-country skiers (11 men and nine women) trained hard for 5 months at either moderate (MIG, 60-70% of VO2max) or high intensity (HIG, 80-90%). The lactate threshold, several performance parameters, and the blood lactate concentration (cLa) after exhausting treadmill running were also determined. Muscle biopsies taken from the vastus lateralis muscle before and after the training period were analysed for the two MCTs and for muscle fibre types and six enzymes. The concentration of MCT1 did not change for HIG (P=0.3) but fell for MIG (-12 +/- 3%, P=0.01); the training response differed between the two groups (P=0.05). The concentration of MCT4 did not change during the training period (P > 0.10). The concentration of the two MCTs did not differ between the two sexes (P=0.9). The running speed at the lactate threshold rose for HIG (+3.2 +/- 0.9%, P=0.003), while no change was seen for MIG (P=0.54); the training response differed between the two groups (P=0.04). The cLa after long-lasting exhausting treadmill running correlated with the concentration of MCT1 (rs=0.69, P=0.002), but not with that of MCT4 (rs=0.2, P=0.2). There were no other significant correlations between the concentrations of the two MCTs and the performance parameters, muscle fibre types, or enzymes (r < or = 0.36, P > 0.10). Thus, the training response differed between MIG and HIG both in terms of performance and of the effect on MCT1. Training at high intensity may be more effective for cross-country skiers. Finally, MCT1 may be important for releasing lactate to the blood during long-lasting exercise. AD - Norwegian University of Sport and Physical Education, Ulleva Stadion, Oslo, Norway. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11683677 ID - 41 ER - TY - JOUR AU - Evertsen, F. AU - Medbo, J. I. AU - Jebens, E. AU - Gjovaag, T. F. PY - 1999 TI - Effect of training on the activity of five muscle enzymes studied on elite cross-country skiers SP - 247-57 N1 - Nov JF - Acta Physiol Scand VL - 167 IS - 3 N1 - Effect of training on the activity of five muscle enzymes studied on elite cross-country skiers N1 - 909 N1 - 10606827 Evertsen, F Medbo, J I Jebens, E Gjovaag, T F Comparative Study England Acta physiologica Scandinavica Acta Physiol Scand. 1999 Nov;167(3):247-57. KW - Adolescent Citrate (si)-Synthase/metabolism Enzymes/*metabolism Exercise Test Female Glycerolphosphate Dehydrogenase/metabolism Humans Hydroxybutyrate Dehydrogenase/metabolism Male Muscle Fibers, Fast-Twitch/*enzymology Muscle Fibers, Slow-Twitch/*enzymology Oxygen Consumption/physiology Phosphofructokinase-1/metabolism Physical Fitness/*physiology Sex Characteristics Skiing/physiology Succinate Dehydrogenase/metabolism Thigh N2 - This study examines the effect of training intensity on the activity of enzymes in m. vastus lateralis. Elite junior cross-country skiers of both sexes trained 12-15 h weeks-1 for 5 months at either moderate (60-70% of VO2max, MIG) or high training intensity (80-90% of the VO2max, close to the lactate threshold; HIG). Muscle biopsies for enzyme analyses and fibre typing were taken before and after the training period. Histochemical analyses on single fibres were done for three enzymes (succinate dehydrogenase [SDH], hydroxybutyrate dehydrogenase [HBDH], glycerol-3-phosphate dehydrogenase [GPDH]), while the activity of citrate synthase [CS] and phosphofructokinase [PFK] was measured on whole biopsies. The activity of GPDH was low in ST fibres and high in FT fibres. The activity of SDH and HBDH was high in both ST and FTa fibres but low in the FTb fibres. The HIG increased their performance more than the MIG did during the training period as judged from scores on a 20-min run test. The SDH activity rose by 6% for the HIG (P < 0.02). No effects of training were found in the activities of CS, HBDH or GPDH, neither in the two training groups nor for the two genders (P > or = 0.16). The PFK activity fell by 10% for the HIG (P=0.02), while no change was found for the MIG. For GPDH, CS and SDH the women's activity was approximately 20% less than the value for the men (P < 0.03). For PFK and HBDH there was no sex difference (P > or = 0.27). There were positive correlations between the activity of three of the enzymes (CS, SDH and GPDH) and the performance parameters (VO2max, cross-country skiing and running performance; r > or = 0.6, P < 0.01). No correlations were found between the PFK or HBDH activities and the performance parameters (r < or = 0.16, P > 0.05). This study suggests that intensities near the lactate threshold affect biochemical and physiological parameters examined in this study as well as the performance of elite skiers, and that the rate-limiting enzymes may be more sensitive to training than non-rate-limiting enzymes. AD - Norwegian University of Sport and Physical Education, Ulleval Stadion, Oslo, Norway. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=10606827 ID - 40 ER - TY - JOUR AU - Evertsen, F. AU - Medbo, J. I. AU - Jebens, E. AU - Nicolaysen, K. PY - 1997 TI - Hard training for 5 mo increases Na(+)-K+ pump concentration in skeletal muscle of cross-country skiers SP - R1417-24 N1 - May JF - Am J Physiol VL - 272 IS - 5 Pt 2 N1 - Hard training for 5 mo increases Na(+)-K+ pump concentration in skeletal muscle of cross-country skiers N1 - 910 N1 - 9176332 Evertsen, F Medbo, J I Jebens, E Nicolaysen, K United states The American journal of physiology Am J Physiol. 1997 May;272(5 Pt 2):R1417-24. KW - Adult Female Humans Male Muscle, Skeletal/*enzymology Oxygen Consumption *Physical Fitness Skiing/*physiology Sodium-Potassium-Exchanging ATPase/*metabolism N2 - To study how training affects the Na(+)-K+ pump concentration, 11 male and 9 female elite junior cross-country skiers trained 12-15 h/wk at 60-70% (moderate-intensity group) or 80-90% (high-intensity group) of their maximal O2 uptake for 5 mo. Muscle biopsies taken from the vastus lateralis muscle before and after the training period were analyzed for Na(+)-K+ pump concentration by the [3H]ouabain-binding technique. Before training, the concentration was 343 +/- 11 nmol/kg wet muscle mass (mean +/- SE) for the men and 281 +/- 14 nmol/kg for the women (18% less than for the men, P = 0.003). The Na(+)-K+ pump concentration rose by 49 +/- 11 nmol/kg (16%, P < 0.001) for all subjects pooled during the training period, and there was no difference between the two training groups (P = 0.3) or the sexes (P = 0.5) in this increase. The Na(+)-K+ pump concentration correlated with the maximal O2 uptake (r = 0.6, P = 0.003), with the performance during a 20-min treadmill run (r = 0.6, P = 0.003), and to the rank of the subjects' performance as cross-country skiers (Spearman's rank correlation coefficient = 0.76, P < 0.001). These data could mean that for elite cross-country skiers the performance is related to the Na(+)-K+ pump concentration. However, other studies have shown an equally high pump concentration for far less fit subjects, suggesting that the pump concentration may not be a limiting factor. AD - Norwegian University of Sport and Physical Education, Ulleval Hageby, Oslo, Norway. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9176332 ID - 39 ER - TY - JOUR AU - Fajen, B.R. AU - Riley, M.A. AU - Turvey, M. PY - 2009 TI - Information, affordances, and the control of action in sport SP - 79-107 JF - International Journal of Sport Psychology VL - 40 IS - 1 N1 - Information, affordances, and the control of action in sport ID - 8 ER - TY - JOUR AU - Fields, R. D. PY - 2006 TI - Nerve impulses regulate myelination through purinergic signalling SP - 148-58; discussion 158-61, 233-7, 275-81 JF - Novartis Found Symp VL - 276 N1 - Nerve impulses regulate myelination through purinergic signalling N1 - 1023 N1 - 16805428 Fields, R Douglas Review England Novartis Foundation symposium Novartis Found Symp. 2006;276:148-58; discussion 158-61, 233-7, 275-81. KW - Action Potentials/physiology Adenosine Triphosphate/*metabolism Animals Axons/*metabolism/ultrastructure Calcium/metabolism Cell Communication/physiology Cells, Cultured Central Nervous System/cytology/physiology Ganglia, Spinal/cytology Myelin Sheath/*metabolism Oligodendroglia/cytology/physiology Peripheral Nervous System/cytology/physiology Receptors, Purinergic P1/*metabolism Schwann Cells/cytology/physiology Signal Transduction/*physiology N2 - The myelin membrane wrapped around axons provides electrical insulation essential for rapid impulse conduction. Impulse activity can affect the formation of myelin, but the effects differ in the PNS and CNS, where myelin is formed by two distinct types of cells: Schwann cells (SCs) and oligodendrocytes, respectively. Our studies on mouse dorsal root ganglion (DRG) neurons, which have axons in both the PNS and CNS, show that impulse activity releases ATP from premyelinated axons, and that this is detected by myelinating glia. Calcium imaging indicates that axonal firing stimulates different purinergic receptors on the two types of glia, resulting in opposite effects of impulse activity on differentiation of SCs and oligodendrocyte progenitor cells (OPCs). In addition to P2 receptors on both types of glia, four types of P1 receptors are present in OPCs, but only A2A and A2BP1 receptors are detected in mouse SCs. ATP is of primary importance in regulating early development and myelination by SCs, where it inhibits differentiation and myelination. Adenosine is of primary importance in regulating early development of OPCs, where it stimulates differentiation and myelination. Purinergic signalling interacts with growth factor and cytokine signalling, and these responses are developmentally regulated. AD - Nervous System Development and Plasticity Section, National Institutes of Health, NICHD, Bethesda, MD 20892, USA. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16805428 ID - 59 ER - TY - JOUR AU - Fiskerstrand, A. AU - Seiler, K. S. PY - 2004 TI - Training and performance characteristics among Norwegian international rowers 1970-2001 SP - 303-10 N1 - Oct JF - Scand J Med Sci Sports VL - 14 IS - 5 N1 - Training and performance characteristics among Norwegian international rowers 1970-2001 N1 - 839 N1 - 15387804 Fiskerstrand, A Seiler, K S Denmark Scandinavian journal of medicine & science in sports Scand J Med Sci Sports. 2004 Oct;14(5):303-10. KW - Altitude Humans Lactates/blood Male Norway Physical Education and Training/*methods Physical Endurance/*physiology Questionnaires Sports/*physiology Time Factors N2 - This study quantified changes in training volume, organization, and physical capacity among Norwegian rowers winning international medals between 1970 and 2001. Twenty-eight athletes were identified (27 alive). Results of physiological testing and performance history were available for all athletes. Twenty-one of 27 athletes responded to a detailed questionnaire regarding their training during their internationally competitive years. Maximal oxygen uptake (VO2 max) increased 12% (6.5+/- 0.4 vs. 5.8+/-0.2 L min(-1)) from the 1970s to the 1990s. Similarly, 6-min ergometer rowing performance increased almost 10%. Three major changes in training characteristics were identified: (1) training at a low blood lactate (< 2 mM) increased from 30 to 50 h month(-1) and race pace and supra-maximal intensity training (approximately 8-14 mM lactate) decreased from 23 to approximately 7 h month(-1); (2) training volume increased by approximately 20%, from 924 to 1128 h yr(-1); (3) altitude training was used as a pre-competition peaking strategy, but it is now integrated into the winter preparation program as periodic 2-3-week altitude camps. The training organization trends are consistent with data collected on athletes from other sports, suggesting a "polarized" pattern of training organization where a high volume of low intensity training is balanced against regular application of training bouts utilizing 90%-95% of VO2 max. AD - Norwegian Rowing Federation, Oslo, Norway. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15387804 ID - 50 ER - TY - JOUR AU - Foster, C. PY - 1998 TI - Monitoring training in athletes with reference to overtraining syndrome SP - 1164-8 N1 - Jul JF - Med Sci Sports Exerc VL - 30 IS - 7 N1 - Monitoring training in athletes with reference to overtraining syndrome N1 - 871 N1 - 9662690 Foster, C United states Medicine and science in sports and exercise Med Sci Sports Exerc. 1998 Jul;30(7):1164-8. KW - Adult Anaerobic Threshold/physiology Athletic Injuries/*etiology Fatigue/etiology Female Heart Rate/physiology Humans Lactic Acid/blood Male *Morbidity Oxygen Consumption/physiology Physical Education and Training/*methods Physical Exertion/*physiology Sports/*physiology/psychology Stress, Psychological/etiology Syndrome N2 - PURPOSE: Overtraining is primarily related to sustained high load training, often coupled with other stressors. Studies in animal models have suggested that unremittingly heavy training (monotonous training) may increase the likelihood of developing overtraining syndrome. The purpose of this study was to extend our preliminary observations by relating the incidence of illnesses and minor injuries to various indices of training. METHODS: We report observations of the relationship of banal illnesses (a frequently cited marker of overtraining syndrome) to training load and training monotony in experienced athletes (N = 25). Athletes recorded their training using a method that integrates the exercise session RPE and the duration of the training session. Illnesses were noted and correlated with indices of training load (rolling 6 wk average), monotony (daily mean/standard deviation), and strain (load x monotony). RESULTS: It was observed that a high percentage of illnesses could be accounted for when individual athletes exceeded individually identifiable training thresholds, mostly related to the strain of training. CONCLUSIONS: These suggest that simple methods of monitoring the characteristics of training may allow the athlete to achieve the goals of training while minimizing undesired training outcomes. AD - Milwaukee Heart Institute, WI, USA. cfoster@facstaff.wisc.edu UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9662690 ID - 47 ER - TY - JOUR AU - Foster, C. AU - Daines, E. AU - Hector, L. AU - Snyder, A. C. AU - Welsh, R. PY - 1996 TI - Athletic performance in relation to training load SP - 370-4 N1 - Jun JF - Wis Med J VL - 95 IS - 6 N1 - Athletic performance in relation to training load N1 - 872 N1 - 8693756 Foster, C Daines, E Hector, L Snyder, A C Welsh, R Research Support, Non-U.S. Gov't United states Wisconsin medical journal Wis Med J. 1996 Jun;95(6):370-4. KW - Adult Evaluation Studies as Topic *Exercise Tolerance Female Humans Male *Physical Education and Training *Sports N2 - Athletic performance generally is thought to improve with increases in training load. However, few data exist showing the quantitative relationship between training load and performance. We followed 56 athletes (16 runners; 40 cyclists/speed skaters) during 12 weeks of training. We recorded index performances (3.2 km time trial or 5 or 10 km bicycle ergometry) after 6 weeks of baseline training and 6 weeks of a self-selected training increases. Training load was quantitated as the product of intensity (global rating of perceived exertion (RPE)) and the duration (time) of each training session. Load was expressed as the weekly average over the 6 weeks preceding each index performance. We also recorded the duration of high intensity training (RPE>5, hard) (inten). From 6 to 12 weeks, performance improved 12.95 +/- 3.83 to 12.66 +/- 3.00 min (p < .01). Training time (345 +/- 282 to 355 +/- 273 min/wk) and inten (61 +/- 88 to 71 +/- 91 min/wk) did not change significantly, although RPE (3.8 +/- 0.7 to 4.0 +/- 0.8) and load (1242 +/- 957 to 1386 +/- 978) increased significantly. No strong correlations existed between changes in performance and changes in any training measure (TIME, r = -0.031, RPE, r = -0.039, LOAD, r = 0.29, INTEN, r = 0.025.) Data suggest that improved performance in events of 7-20 minutes duration in response to intensified training is primarily dependent upon increases in total load and overall RPE during training and; that a 10-fold increase in training load may be associated with an approximately 10% improvement in performance. These data suggest the possibility of understanding the training responses of athletes on a quantitative basis. AD - Milwaukee Heart Institute, WI 53201-0342, USA. cfoster@facstaff.wisc.edu UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8693756 ID - 46 ER - TY - JOUR AU - Foster, C. AU - Florhaug, J. A. AU - Franklin, J. AU - Gottschall, L. AU - Hrovatin, L. A. AU - Parker, S. AU - Doleshal, P. AU - Dodge, C. PY - 2001 TI - A new approach to monitoring exercise training SP - 109-15 N1 - Feb JF - J Strength Cond Res VL - 15 IS - 1 N1 - A new approach to monitoring exercise training N1 - 963 N1 - 11708692 Foster, C Florhaug, J A Franklin, J Gottschall, L Hrovatin, L A Parker, S Doleshal, P Dodge, C Comparative Study Evaluation Studies United States Journal of strength and conditioning research / National Strength & Conditioning Association J Strength Cond Res. 2001 Feb;15(1):109-15. KW - Adult Basketball/physiology Exercise Test/methods Female Heart Rate/*physiology Humans Lactic Acid/blood Male Monitoring, Physiologic/*methods Perception/physiology Physical Education and Training/*methods Physical Exertion/*physiology Regression Analysis Time Factors N2 - The ability to monitor training is critical to the process of quantitating training periodization plans. To date, no method has proven successful in monitoring training during multiple types of exercise. High-intensity exercise training is particularly difficult to quantitate. In this study we evaluate the ability of the session rating of perceived exertion (RPE) method to quantitate training during non-steady state and prolonged exercise compared with an objective standard based on heart rate (HR). In a 2-part design, subjects performed steady state and interval cycle exercise or practiced basketball. Exercise bouts were quantitated using both the session RPE method and an objective HR method. During cycle exercise, the relationship between the exercise score derived using the session RPE method and the HR method was highly consistent, although the absolute score was significantly greater with the session RPE method. During basketball, there was a consistent relationship between the 2 methods of monitoring exercise, although the absolute score was also significantly greater with the session RPE method. Despite using different subjects in the 2 parts of the study, the regression relationships between the session RPE method and the HR method were nearly overlapping, suggesting the broad applicability of this method. We conclude that the session RPE method is a valid method of quantitating exercise training during a wide variety of types of exercise. As such, this technique may hold promise as a mode and intensity-independent method of quantitating exercise training and may provide a tool to allow the quantitative evaluation of training periodization plans. AD - Department of Exercise and Sport Science, University of Wisconsin-La Crosse, 54601, USA. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11708692 ID - 45 ER - TY - JOUR AU - Foster, C. AU - Heiman, K. M. AU - Esten, P. L. AU - Brice, G. AU - Porcari, J. PY - 2001 TI - Differences in perceptions of training by coaches and athletes SP - 3-7 JF - South African Journal of Sports Medicine VL - 8 N1 - Differences in perceptions of training by coaches and athletes N1 - 1062 ID - 35 ER - TY - JOUR AU - Foster, C. AU - Hoyos, J. AU - Earnest, C. AU - Lucia, A. PY - 2005 TI - Regulation of energy expenditure during prolonged athletic competition SP - 670-5 N1 - Apr JF - Med Sci Sports Exerc VL - 37 IS - 4 N1 - Regulation of energy expenditure during prolonged athletic competition N1 - 646 N1 - 15809568 Foster, Carl Hoyos, Jesus Earnest, Conrad Lucia, Alejandro United States Medicine and science in sports and exercise Med Sci Sports Exerc. 2005 Apr;37(4):670-5. KW - Adaptation, Physiological/physiology Adult Analysis of Variance Bicycling/*physiology Competitive Behavior/physiology Energy Metabolism/*physiology Heart Rate/*physiology Humans Physical Exertion/physiology Time Factors N2 - BACKGROUND: Athletic competitions, such as the Tour de France, demand both momentary bursts of very high power output and the ability to provide high levels of energy expenditure for several weeks. As such, they provide a model of the ability for sustained muscular activity, which is important in terms of how humans are understood, not only as athletes, but also within an evolutionary context. METHODS: Laboratory correlated HR responses were made of elite professional cyclists (N=7) during successive competitions in one of the three grand tours in cycling in successive years, with the intent of evaluating the magnitude and pattern of energy expenditure. HR recordings were normalized into a training impulse (TRIMP) score, summating the intensity and duration of each race, and tracked over the duration of successive tours. RESULTS: Although the day-by-day pattern of HR responses in exercise intensity zones associated with exercise intensities below the first ventilatory threshold, between the first and second ventilatory thresholds, and above the second ventilatory threshold varied in response to the course and competitive situation, the net accumulation of both time in each of the HR zones and TRIMP was remarkably constant from one tour to the next, both within the group at large as well as within individual athletes. The magnitude of accumulation of TRIMP was similar to that of previous reports on elite tour cyclists. CONCLUSIONS: We interpret these results as evidence that humans adopt a pacing strategy designed to optimally distribute energy reserves over the duration of each tour. AD - Department of Exercise and Sport Science, University of Wisconsin-La Crosse, La Crosse, WI 54601, USA. foster.carl@uwlax.edu UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15809568 ID - 44 ER - TY - JOUR AU - Frank, D. AU - Kuhn, C. AU - Brors, B. AU - Hanselmann, C. AU - Ludde, M. AU - Katus, H. A. AU - Frey, N. PY - 2008 TI - Gene expression pattern in biomechanically stretched cardiomyocytes: evidence for a stretch-specific gene program SP - 309-18 N1 - Feb JF - Hypertension VL - 51 IS - 2 N1 - Gene expression pattern in biomechanically stretched cardiomyocytes: evidence for a stretch-specific gene program N1 - 1042 N1 - 18158353 Frank, Derk Kuhn, Christian Brors, Benedikt Hanselmann, Christiane Ludde, Mark Katus, Hugo A Frey, Norbert Comparative Study Research Support, Non-U.S. Gov't United States Hypertension Hypertension. 2008 Feb;51(2):309-18. Epub 2007 Dec 24. KW - Adrenergic alpha-Agonists/pharmacology Angiotensin II/metabolism/pharmacology Animals Animals, Newborn *Gene Expression/drug effects Gene Expression Profiling Genome Heart Ventricles Hypertrophy/chemically induced/etiology Microarray Analysis Myocytes, Cardiac/drug effects/*metabolism/*pathology Phenylephrine/pharmacology Rats Receptors, Angiotensin/metabolism Signal Transduction Stress, Mechanical N2 - Biomechanical stress ie, attributable to pressure overload, leads to cardiac hypertrophy and may ultimately cause heart failure. Yet, it is still unclear how mechanical stress is sensed and transduced on the molecular level. To systematically elucidate the underlying signal transduction pathways, we analyzed the gene expression profile of stretched cardiomyocytes on a genome-wide scale in comparison with other inducers of hypertrophy such as pharmacological stimulation. Neonatal rat ventricular cardiomyocytes were either stretched biaxially or stimulated with phenylephrine (PE), both resulting in a similar degree of hypertrophy. Microarray analyses revealed 164 genes >2.0-fold up- and 21 genes <0.5-fold downregulated (P<0.01). Differential expression was confirmed by real-time polymerase chain reaction. Genes of the "fetal gene program" such as BNP were induced by both stretch (4.2x) and PE (2.9x). We also verified upregulation of known stretch-responsive genes, including HSP70 (20.9x) and c-myc (3.0x). Moreover, several genes were found to be preferentially induced by stretch, such as the cardioprotective cytokine GDF15 (24.8x) and heme oxygenase 1 (Hmox1, 10.8x; both confirmed on protein level). Neither PE nor endothelin-1 upregulated GDF15 and Hmox1, whereas angiotensin II significantly induced both genes. Conversely, the AT(1) receptor blocker irbesartan markedly blunted stretch-mediated GDF15 and Hmox1 upregulation, suggesting that the angiotensin receptor transduces the biomechanical induction of these genes. In conclusion, we report a comprehensive gene expression profile of cardiomyocytes subjected to biomechanical stress in comparison with pharmacologically induced hypertrophy. Our data imply that a stretch-specific gene program exists, which is mediated, at least in part, by angiotensin II-dependent signaling. AD - Department of Internal Medicine III, University of Heidelberg, Heidelberg, Germany. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=18158353 ID - 69 ER - TY - JOUR AU - Frank, T. AU - Michelbrink, M. AU - Beckmann, H. AU - Schöllhorn, W. PY - 2008 TI - A quantitative dynamical systems approach to differential learning: self-organization principle and order parameter equations SP - 19-31 JF - Biological Cybernetics VL - 98 IS - 1 N1 - A quantitative dynamical systems approach to differential learning: self-organization principle and order parameter equations N1 - 10.1007/s00422-007-0193-x N2 - Abstract  Differential learning is a learning concept that assists subjects to find individual optimal performance patterns for given complex motor skills. To this end, training is provided in terms of noisy training sessions that feature a large variety of between-exercises differences. In several previous experimental studies it has been shown that performance improvement due to differential learning is higher than due to traditional learning and performance improvement due to differential learning occurs even during post-training periods. In this study we develop a quantitative dynamical systems approach to differential learning. Accordingly, differential learning is regarded as a self-organized process that results in the emergence of subject- and context-dependent attractors. These attractors emerge due to noise-induced bifurcations involving order parameters in terms of learning rates. In contrast, traditional learning is regarded as an externally driven process that results in the emergence of environmentally specified attractors. Performance improvement during post-training periods is explained as an hysteresis effect. An order parameter equation for differential learning involving a fourth-order polynomial potential is discussed explicitly. New predictions concerning the relationship between traditional and differential learning are derived. UR - http://dx.doi.org/10.1007/s00422-007-0193-x ID - 9 ER - TY - JOUR AU - Fry, A. C. AU - Schilling, B. K. AU - Weiss, L. W. AU - Chiu, L. Z. PY - 2006 TI - beta2-Adrenergic receptor downregulation and performance decrements during high-intensity resistance exercise overtraining SP - 1664-72 N1 - Dec JF - J Appl Physiol VL - 101 IS - 6 N1 - beta2-Adrenergic receptor downregulation and performance decrements during high-intensity resistance exercise overtraining N1 - 1061 N1 - 16888042 Fry, Andrew C Schilling, Brian K Weiss, Lawrence W Chiu, Loren Z F Randomized Controlled Trial Research Support, Non-U.S. Gov't United States Journal of applied physiology (Bethesda, Md. : 1985) J Appl Physiol. 2006 Dec;101(6):1664-72. Epub 2006 Aug 3. KW - Adult Down-Regulation Exercise/*physiology Exercise Tolerance/*physiology Humans Male Muscle, Skeletal/*physiology Physical Exertion/*physiology Psychomotor Performance/*physiology Receptors, Adrenergic, beta-2/*metabolism N2 - Previous research on overtraining due to excessive use of maximal resistance exercise loads [100% 1 repetition maximum (1 RM)] indicates that peripheral muscle maladaptation contributes to overtraining-induced performance decrements. This study examined the cellular and molecular responses of skeletal muscle to performance decrements due to high-relative-intensity (%1 RM) resistance exercise overtraining. Weight-trained men were divided into overtrained (OT, n = 8) and control (Con, n = 8) groups. The OT group performed 10 x 1 at 100% 1 RM daily for 2 wk, whereas the Con group performed normal training 2 days/wk. Muscle biopsies from the vastus lateralis muscle, voluntary static and dynamic muscle performances, and nocturnal urinary epinephrine were assessed before (pre) and after (post) overtraining. Overtraining occurred as indicated by a decrease in 1-RM strength for the OT group (mean +/- SE; OT pre = 159.3 +/- 10.1 kg, OT post = 151.4 +/- 9.9 kg, Con pre = 146.0 +/- 12.9 kg, Con post = 144.9 +/- 13.3 kg), as well as a 36.3% decrease in mean power at 100% 1-RM loads. Normal training could be resumed only after 2-8 wk of training cessation. Muscle beta(2)-adrenergic receptor (beta(2)-AR; fmol/mg protein) density significantly decreased by 37.0% for the OT group and was unchanged for the Con group (-1.8%). Nocturnal urinary epinephrine for the OT group increased by 49%, although this was not significant (effect size = 0.42). The ratio of nocturnal urinary epinephrine to beta(2)-AR density suggested a decreased beta(2)-AR sensitivity for the OT group (2.4-fold increase). Overtraining occurred based on decreased muscular force and power. Desensitization of the beta(2)-AR system suggests that this may be an important contributor to performance decrements due to excessive use of maximal resistance exercise loads. AD - Human Performance Laboratories, The University of Memphis, Department of Health and Sport Sciences, Memphis, Tennessee, USA. afry@memphis.edu UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16888042 ID - 61 ER - TY - JOUR AU - Gaskill, S. E. AU - Serfass, R. C. AU - Bacharach, D. W. AU - Kelly, J. M. PY - 1999 TI - Responses to training in cross-country skiers SP - 1211-7 N1 - Aug JF - Med Sci Sports Exerc VL - 31 IS - 8 N1 - Responses to training in cross-country skiers N1 - 906 N1 - 10449026 Gaskill, S E Serfass, R C Bacharach, D W Kelly, J M Clinical Trial United states Medicine and science in sports and exercise Med Sci Sports Exerc. 1999 Aug;31(8):1211-7. KW - Adult Female Humans Male *Oxygen Consumption Physical Endurance/*physiology Skiing/*physiology Task Performance and Analysis N2 - PURPOSE: This study evaluated whether cross-country skiers who did not respond positively to a training program consisting of high volume and low intensity would improve if high-intensity training volume was doubled during a subsequent training year. METHODS: During the first year of the study, cross-country skiers (N = 14) were evaluated for VO2max, VO2threshold, lactate response, max arm power, and competitive results after a standard training program. During the second year, the athletes were divided into a control group (athletes who had responded well to the training) and a treatment group (athletes who had responded poorly to the training). The control group (N = 7) repeated the previous year's training program. The treatment group (N = 7) was given a modified training program which increased high-intensity training time as a percentage of total training from < 17% to > 35% and decreased low-intensity training volume 22%. RESULTS: The treatment group, using the high-intensity training program, demonstrated significantly improved VO2max, VO2threshold, max arm power, and competitive results (P < 0.05). CONCLUSIONS: Increased volume of high-intensity training may improve competitive results in cross-country skiers who fail to respond to increased volume of low-intensity training. AD - University of Montana, Department of Health and Human Performance, Missoula 59812, USA. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=10449026 ID - 38 ER - TY - JOUR AU - Gladden, L. B. PY - 2004 TI - Lactate metabolism: a new paradigm for the third millennium SP - 5-30 N1 - Jul 1 JF - J Physiol VL - 558 IS - Pt 1 N1 - Lactate metabolism: a new paradigm for the third millennium N1 - 563 N1 - 15131240 Gladden, L B Review England The Journal of physiology J Physiol. 2004 Jul 1;558(Pt 1):5-30. Epub 2004 May 6. KW - Acidosis, Lactic/*metabolism Animals Energy Metabolism/*physiology Exercise/*physiology Humans Lactic Acid/*metabolism N2 - For much of the 20th century, lactate was largely considered a dead-end waste product of glycolysis due to hypoxia, the primary cause of the O2 debt following exercise, a major cause of muscle fatigue, and a key factor in acidosis-induced tissue damage. Since the 1970s, a 'lactate revolution' has occurred. At present, we are in the midst of a lactate shuttle era; the lactate paradigm has shifted. It now appears that increased lactate production and concentration as a result of anoxia or dysoxia are often the exception rather than the rule. Lactic acidosis is being re-evaluated as a factor in muscle fatigue. Lactate is an important intermediate in the process of wound repair and regeneration. The origin of elevated [lactate] in injury and sepsis is being re-investigated. There is essentially unanimous experimental support for a cell-to-cell lactate shuttle, along with mounting evidence for astrocyte-neuron, lactate-alanine, peroxisomal and spermatogenic lactate shuttles. The bulk of the evidence suggests that lactate is an important intermediary in numerous metabolic processes, a particularly mobile fuel for aerobic metabolism, and perhaps a mediator of redox state among various compartments both within and between cells. Lactate can no longer be considered the usual suspect for metabolic 'crimes', but is instead a central player in cellular, regional and whole body metabolism. Overall, the cell-to-cell lactate shuttle has expanded far beyond its initial conception as an explanation for lactate metabolism during muscle contractions and exercise to now subsume all of the other shuttles as a grand description of the role(s) of lactate in numerous metabolic processes and pathways. AD - Department of Health and Human Performance, 2050 Memorial Coliseum, Auburn University, Auburn, AL 36849-5323, USA. gladdlb@auburn.edu UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15131240 ID - 107 ER - TY - JOUR AU - Glazier, P. AU - Davids, K. AU - Renshaw, I. AU - Button, C. PY - 2005 TI - Uncovering the secrets of 'the Don' - Bradman reassessed SP - 16-21 JF - Sport Health VL - 22 N1 - Uncovering the secrets of 'the Don' - Bradman reassessed ID - 10 ER - TY - JOUR AU - Gledhill, N. AU - Cox, D. AU - Jamnik, R. PY - 1994 TI - Endurance athletes' stroke volume does not plateau: major advantage is diastolic function SP - 1116-21 N1 - Sep JF - Med Sci Sports Exerc VL - 26 IS - 9 N1 - Endurance athletes' stroke volume does not plateau: major advantage is diastolic function N1 - 555 N1 - 7808245 Gledhill, N Cox, D Jamnik, R Research Support, Non-U.S. Gov't United states Medicine and science in sports and exercise Med Sci Sports Exerc. 1994 Sep;26(9):1116-21. KW - Adult Blood Pressure Blood Volume *Diastole Humans Male Physical Endurance/*physiology Sports/*physiology *Stroke Volume Ventricular Function, Left N2 - Left ventricular function was examined during incremental work rates to maximum using simultaneous determinations of stroke volume, left ventricular ejection time (LVET), and diastolic filling time (DT). Seven endurance trained and seven untrained young adult males were studied on a cycle ergometer at matched heart rates of 90, 120, 140, 160, 180, and 190 bpm (+/- 1 bpm). Stroke volume of the untrained subjects reached a plateau at 120 bpm, but stroke volume of the trained subjects continued to increase to their maximum heart rate with no plateau. Throughout incremental work rates, LVET was significantly longer and DT was significantly shorter in the trained subjects. At a heart rate of 190 bpm, the corresponding rates of ventricular emptying and ventricular filling of the trained versus the untrained subjects were 20% and 71% greater, respectively (P < 0.01). We conclude that during incremental work rates the stroke volume of endurance trained athletes increases progressively to maximum with no plateau. In addition, although trained athletes rely on enhancements in both ventricular filling and ventricular emptying to augment stroke volume, by far their major advantage over untrained subjects is in ventricular filling. AD - York University, Toronto, Canada. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=7808245 ID - 106 ER - TY - JOUR AU - Gomez-Cabrera, M. C. AU - Domenech, E. AU - Romagnoli, M. AU - Arduini, A. AU - Borras, C. AU - Pallardo, F. V. AU - Sastre, J. AU - Vina, J. PY - 2008 TI - Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance SP - 142-9 N1 - Jan JF - Am J Clin Nutr VL - 87 IS - 1 N1 - Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance N1 - 1119 N1 - 18175748 Gomez-Cabrera, Mari-Carmen Domenech, Elena Romagnoli, Marco Arduini, Alessandro Borras, Consuelo Pallardo, Federico V Sastre, Juan Vina, Jose Randomized Controlled Trial Research Support, Non-U.S. Gov't United States The American journal of clinical nutrition Am J Clin Nutr. 2008 Jan;87(1):142-9. KW - Adaptation, Physiological/*drug effects/physiology Administration, Oral Adult Animals Antioxidants/*administration & dosage/pharmacology Ascorbic Acid/*administration & dosage/pharmacology Cross-Over Studies DNA-Binding Proteins/metabolism Dietary Supplements Double-Blind Method Humans Male Mitochondria, Muscle/*drug effects/metabolism Mitochondrial Proteins/metabolism Nuclear Respiratory Factor 1/metabolism Oxidative Stress/*drug effects Oxygen Consumption Peroxisome Proliferator-Activated Receptors/metabolism *Physical Endurance/drug effects/physiology Rats Rats, Wistar Reactive Oxygen Species Transcription Factors/metabolism N2 - BACKGROUND: Exercise practitioners often take vitamin C supplements because intense muscular contractile activity can result in oxidative stress, as indicated by altered muscle and blood glutathione concentrations and increases in protein, DNA, and lipid peroxidation. There is, however, considerable debate regarding the beneficial health effects of vitamin C supplementation. OBJECTIVE: This study was designed to study the effect of vitamin C on training efficiency in rats and in humans. DESIGN: The human study was double-blind and randomized. Fourteen men (27-36 y old) were trained for 8 wk. Five of the men were supplemented daily with an oral dose of 1 g vitamin C. In the animal study, 24 male Wistar rats were exercised under 2 different protocols for 3 and 6 wk. Twelve of the rats were treated with a daily dose of vitamin C (0.24 mg/cm2 body surface area). RESULTS: The administration of vitamin C significantly (P=0.014) hampered endurance capacity. The adverse effects of vitamin C may result from its capacity to reduce the exercise-induced expression of key transcription factors involved in mitochondrial biogenesis. These factors are peroxisome proliferator-activated receptor co-activator 1, nuclear respiratory factor 1, and mitochondrial transcription factor A. Vitamin C also prevented the exercise-induced expression of cytochrome C (a marker of mitochondrial content) and of the antioxidant enzymes superoxide dismutase and glutathione peroxidase. CONCLUSION: Vitamin C supplementation decreases training efficiency because it prevents some cellular adaptations to exercise. AD - Department of Physiology, Faculty of Medicine, University of Valencia, Valencia, Spain. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=18175748 ID - 74 ER - TY - JOUR AU - Gorostiaga, E. M. AU - Walter, C. B. AU - Foster, C. AU - Hickson, R. C. PY - 1991 TI - Uniqueness of interval and continuous training at the same maintained exercise intensity SP - 101-7 JF - Eur J Appl Physiol Occup Physiol VL - 63 IS - 2 N1 - Uniqueness of interval and continuous training at the same maintained exercise intensity N1 - 458 N1 - 1748098 Gorostiaga, E M Walter, C B Foster, C Hickson, R C Research Support, Non-U.S. Gov't Germany European journal of applied physiology and occupational physiology Eur J Appl Physiol Occup Physiol. 1991;63(2):101-7. KW - Adult Exercise/*physiology Exercise Test Female Heart Rate/physiology Humans Lactates/blood Male Muscles/enzymology/physiology Oxygen Consumption/physiology *Physical Education and Training Respiration/physiology N2 - The present study sought to evaluate the inconsistencies previously observed regarding the predominance of continuous or interval training for improving fitness. The experimental design initially equated and subsequently maintained the same relative exercise intensity by both groups throughout the program. Twelve subjects were equally divided into continuous (CT, exercise at 50% maximal work) or interval (IT, 30 s work, 30 s rest at 100% maximal work) training groups that cycled 30 min day-1, 3 days.week-1, for 8 weeks. Following training, aerobic power (VO2max), exercising work rates, and peak power output were all higher (9-16%) after IT than after CT (5-7%). Vastus lateralis muscle citrate synthase activity increased 25% after CT but not after IT. A consistent increase in adenylate kinase activity (25%) was observed only after IT. During continuous cycling testing the CT group had reduced blood lactate (lab) levels and respiratory quotient at both the same absolute and relative (70% VO2max) work rates after training, while the IT group displayed similar changes only at the same absolute work rates. By contrast, both groups responded similarly during intermittent cycling testing with lower lab concentrations seen only at absolute work rates. These results show that, of the two types of training programs currently employed, IT produces higher increases in VO2max and in maximal exercise capacity. Nevertheless, CT is more effective at increasing muscle oxidative capacity and delaying the accumulation of lab during continuous exercise. AD - College of Kinesiology, University of Illinois, Chicago 60680. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=1748098 ID - 102 ER - TY - JOUR AU - Gregory, L. W. PY - 1979 TI - The development of aerobic capacity: a comparison of continuous and interval training SP - 199-206 N1 - May JF - Res Q VL - 50 IS - 2 N1 - The development of aerobic capacity: a comparison of continuous and interval training N1 - 88 N1 - 472459 Gregory, L W Comparative Study United states Research quarterly Res Q. 1979 May;50(2):199-206. KW - Adolescent Adult Heart Rate Humans *Lung Volume Measurements Male Oxygen Consumption Physical Education and Training/*methods Physical Endurance UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=472459 ID - 109 ER - TY - BOOK AU - Griffiths, I W PY - 2006 BT - Principles of Biomechanics and Motion Analysis CY - Baltimore, MD PB - Lippincott Williams & Wilkins N1 - Principles of Biomechanics and Motion Analysis ID - 22 ER - TY - JOUR AU - Guadagnoli, M. AU - Lee, T.D. PY - 2004 TI - Challenge point: a framework for conceptualizing the effects of various practice conditions in motor learning. SP - 212-224 JF - Journal of Motor Behavior VL - 36 N1 - Challenge point: a framework for conceptualizing the effects of various practice conditions in motor learning. ID - 11 ER - TY - JOUR AU - Gullich, A. AU - Emrich, E. AU - Seiler, S. PY - 2009 TI - Training Methods and Intensity Distribution of Young World Class Rowers SP - In Press JF - International Journal of Sport Physiology and Performance VL - 4 IS - 4 N1 - Training Methods and Intensity Distribution of Young World Class Rowers N1 - 1397 ID - 49 ER - TY - JOUR AU - Gurland, J. AU - Tripathi, R. C. PY - 1971 TI - A simple approximation for unbiased estimation of the standard deviation SP - 30-32 JF - American Statistician VL - 25(4) N1 - A simple approximation for unbiased estimation of the standard deviation N1 - 73 ID - 152 ER - TY - JOUR AU - Halson, S. L. AU - Jeukendrup, A. E. PY - 2004 TI - Does overtraining exist? An analysis of overreaching and overtraining research SP - 967-81 JF - Sports Med VL - 34 IS - 14 N1 - Does overtraining exist? An analysis of overreaching and overtraining research N1 - 689 N1 - 15571428 Halson, Shona L Jeukendrup, Asker E Review New Zealand Sports medicine (Auckland, N.Z.) Sports Med. 2004;34(14):967-81. KW - Catecholamines/urine Exercise/*physiology Glutamine/blood Glycogen/metabolism Heart Rate Humans Hydrocortisone/blood Research Sports/*physiology Testosterone/blood N2 - Athletes experience minor fatigue and acute reductions in performance as a consequence of the normal training process. When the balance between training stress and recovery is disproportionate, it is thought that overreaching and possibly overtraining may develop. However, the majority of research that has been conducted in this area has investigated overreached and not overtrained athletes. Overreaching occurs as a result of intensified training and is often considered a normal outcome for elite athletes due to the relatively short time needed for recovery (approximately 2 weeks) and the possibility of a supercompensatory effect. As the time needed to recover from the overtraining syndrome is considered to be much longer (months to years), it may not be appropriate to compare the two states. It is presently not possible to discern acute fatigue and decreased performance experienced from isolated training sessions, from the states of overreaching and overtraining. This is partially the result of a lack of diagnostic tools, variability of results of research studies, a lack of well controlled studies and individual responses to training.The general lack of research in the area in combination with very few well controlled investigations means that it is very difficult to gain insight into the incidence, markers and possible causes of overtraining. There is currently no evidence aside from anecdotal information to suggest that overreaching precedes overtraining and that symptoms of overtraining are more severe than overreaching. It is indeed possible that the two states show different defining characteristics and the overtraining continuum may be an oversimplification. Critical analysis of relevant research suggests that overreaching and overtraining investigations should be interpreted with caution before recommendations for markers of overreaching and overtraining can be proposed. Systematically controlled and monitored studies are needed to determine if overtraining is distinguishable from overreaching, what the best indicators of these states are and the underlying mechanisms that cause fatigue and performance decrements. The available scientific and anecdotal evidence supports the existence of the overtraining syndrome; however, more research is required to state with certainty that the syndrome exists. AD - Human Performance Laboratory, School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, UKDepartment of Physiology, Australian Institute of Sport, Belconnen, ACT, Australia. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15571428 ID - 91 ER - TY - JOUR AU - Hanin, Y. L. PY - 2003 TI - Performance related emotional states in sport: a qualitative analysis SP - qualitative-research.net/fqs-texte/1-03/1-03hanin-e.htm JF - Forum: Qualitative Social Research VL - 4(1) N1 - Performance related emotional states in sport: a qualitative analysis N1 - 1 ID - 156 ER - TY - JOUR AU - Hansen, A. K. AU - Fischer, C. P. AU - Plomgaard, P. AU - Andersen, J. L. AU - Saltin, B. AU - Pedersen, B. K. PY - 2005 TI - Skeletal muscle adaptation: training twice every second day vs. training once daily SP - 93-9 N1 - Jan JF - J Appl Physiol VL - 98 IS - 1 N1 - Skeletal muscle adaptation: training twice every second day vs. training once daily N1 - 824 N1 - 15361516 Hansen, Anne K Fischer, Christian P Plomgaard, Peter Andersen, Jesper Lovind Saltin, Bengt Pedersen, Bente Klarlund Clinical Trial Randomized Controlled Trial Research Support, Non-U.S. Gov't United States Journal of applied physiology (Bethesda, Md. : 1985) J Appl Physiol. 2005 Jan;98(1):93-9. Epub 2004 Sep 10. KW - Adaptation, Physiological/physiology Adult Citrate (si)-Synthase/*metabolism Exercise/*physiology Glycogen/*metabolism Humans Male Muscle Contraction/*physiology Muscle Fibers, Skeletal/physiology Muscle Proteins/metabolism Muscle, Skeletal/*physiology Physical Education and Training/methods Physical Endurance/*physiology Physical Exertion/*physiology N2 - Low muscle glycogen content has been demonstrated to enhance transcription of a number of genes involved in training adaptation. These results made us speculate that training at a low muscle glycogen content would enhance training adaptation. We therefore performed a study in which seven healthy untrained men performed knee extensor exercise with one leg trained in a low-glycogen (Low) protocol and the other leg trained at a high-glycogen (High) protocol. Both legs were trained equally regarding workload and training amount. On day 1, both legs (Low and High) were trained for 1 h followed by 2 h of rest at a fasting state, after which one leg (Low) was trained for an additional 1 h. On day 2, only one leg (High) trained for 1 h. Days 1 and 2 were repeated for 10 wk. As an effect of training, the increase in maximal workload was identical for the two legs. However, time until exhaustion at 90% was markedly more increased in the Low leg compared with the High leg. Resting muscle glycogen and the activity of the mitochondrial enzyme 3-hydroxyacyl-CoA dehydrogenase increased with training, but only significantly so in Low, whereas citrate synthase activity increased in both Low and High. There was a more pronounced increase in citrate synthase activity when Low was compared with High. In conclusion, the present study suggests that training twice every second day may be superior to daily training. AD - Dept. of Infectious Diseases M7641, and The Copenhagen Muscle Research Centre, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15361516 ID - 73 ER - TY - JOUR AU - Helgerud, J. AU - Hoydal, K. AU - Wang, E. AU - Karlsen, T. AU - Berg, P. AU - Bjerkaas, M. AU - Simonsen, T. AU - Helgesen, C. AU - Hjorth, N. AU - Bach, R. AU - Hoff, J. PY - 2007 TI - Aerobic high-intensity intervals improve VO2max more than moderate training SP - 665-71 N1 - Apr JF - Med Sci Sports Exerc VL - 39 IS - 4 N1 - Aerobic high-intensity intervals improve VO2max more than moderate training N1 - 864 N1 - 17414804 Helgerud, Jan Hoydal, Kjetill Wang, Eivind Karlsen, Trine Berg, Palr Bjerkaas, Marius Simonsen, Thomas Helgesen, Cecilies Hjorth, Ninal Bach, Ragnhild Hoff, Jan Randomized Controlled Trial United States Medicine and science in sports and exercise Med Sci Sports Exerc. 2007 Apr;39(4):665-71. KW - Adult Exercise/*physiology Humans Male Monitoring, Physiologic Norway Oxygen Consumption/*physiology N2 - PURPOSE: The present study compared the effects of aerobic endurance training at different intensities and with different methods matched for total work and frequency. Responses in maximal oxygen uptake (VO2max), stroke volume of the heart (SV), blood volume, lactate threshold (LT), and running economy (CR) were examined. METHODS: Forty healthy, nonsmoking, moderately trained male subjects were randomly assigned to one of four groups:1) long slow distance (70% maximal heart rate; HRmax); 2)lactate threshold (85% HRmax); 3) 15/15 interval running (15 s of running at 90-95% HRmax followed by 15 s of active resting at 70% HRmax); and 4) 4 x 4 min of interval running (4 min of running at 90-95% HRmax followed by 3 min of active resting at 70%HRmax). All four training protocols resulted in similar total oxygen consumption and were performed 3 d.wk for 8 wk. RESULTS: High-intensity aerobic interval training resulted in significantly increased VO2max compared with long slow distance and lactate-threshold training intensities (P<0.01). The percentage increases for the 15/15 and 4 x 4 min groups were 5.5 and 7.2%, respectively, reflecting increases in V O2max from 60.5 to 64.4 mL x kg(-1) x min(-1) and 55.5 to 60.4 mL x kg(-1) x min(-1). SV increased significantly by approximately 10% after interval training (P<0.05). CONCLUSIONS:: High-aerobic intensity endurance interval training is significantly more effective than performing the same total work at either lactate threshold or at 70% HRmax, in improving VO2max. The changes in VO2max correspond with changes in SV, indicating a close link between the two. AD - Department of Circulation and Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. Jan.Helgerud@ntnu.no UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=17414804 ID - 127 ER - TY - JOUR AU - Henriksson, J. AU - Reitman, J. S. PY - 1976 TI - Quantitative measures of enzyme activities in type I and type II muscle fibres of man after training SP - 392-7 N1 - Jul JF - Acta Physiol Scand VL - 97 IS - 3 N1 - Quantitative measures of enzyme activities in type I and type II muscle fibres of man after training N1 - 550 N1 - 134623 Henriksson, J Reitman, J S Sweden Acta physiologica Scandinavica Acta Physiol Scand. 1976 Jul;97(3):392-7. KW - Adult Humans Muscles/*enzymology Oxygen Consumption Phosphofructokinase-1/*metabolism *Physical Exertion Respiration Succinate Dehydrogenase/*metabolism N2 - The effect of 7 to 8 weeks of physical training on oxidative and glycolytic enzyme activities in the 2 major fibre types of human quadriceps femoris muscle has been investigated. 2 groups of 4 and 5 subjects respectively were trained at the same total work-load on a bicycle ergometer 3 days per week using interval exercise with maximal intensity (I.T.) or continuous exercise with submaximal intensity (C.T.). Succcinate dehydrogenase (SDH) and phosphofructokinase (PFK) activities were determined on crude homogenates of muscle biopsy samples and on pools of type I and type II fibres dissected from freeze-dried samples taken before and after training. Crude homogenate SDH activity increased to the same extent in both groups, average increases were 27.5% (I.T.) and 22% (C.T.) respectively. Only type I-SDH increased in the C.T. group (p less than 0.01), the average increase being 32%. On the other hand only type II-SDH increased in the I.T. group (p less than 0.01), with an average increase of 49%. No changes in PFK activity could be detected. The results of the present study emphasize the great adaptability in oxidative potential of both the two major human skeletal muscle fibre types and further that this adaptation seems to be related to the pattern of fibre recruitment during exercise. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=134623 ID - 114 ER - TY - JOUR AU - Hill, A. V. AU - Long, C. N. H. AU - Lupton, H. PY - 1924 TI - Muscular exercise, lactic acid, and the supply and utilization of oxygen. Parts IV-VI SP - 84-138 JF - Proc. R. Soc. Lond. B. Biol. Sci. VL - 97 N1 - Muscular exercise, lactic acid, and the supply and utilization of oxygen. Parts IV-VI N1 - 1403 ID - 123 ER - TY - JOUR AU - Hill, A. V. AU - Long, C. N. H. AU - Lupton, H. PY - 1924 TI - Muscular exercise, lactic acid, and the supply and utilization of oxygen. Parts I-III SP - 438-475 JF - Proc. R. Soc. Lond. B. Biol. Sci. VL - 96 N1 - Muscular exercise, lactic acid, and the supply and utilization of oxygen. Parts I-III N1 - 1402 ID - 124 ER - TY - JOUR AU - Hirsch, J E PY - 2005 TI - An index to quantify an individual’s scientific research output SP - 16569–16572 JF - Proceedings of the National Academy of Sciences VL - 102 N1 - An index to quantify an individual’s scientific research output ID - 32 ER - TY - JOUR AU - Holloszy, J. O. PY - 2008 TI - Regulation by exercise of skeletal muscle content of mitochondria and GLUT4 SP - 5-18 N1 - Dec JF - J Physiol Pharmacol VL - 59 Suppl 7 N1 - Regulation by exercise of skeletal muscle content of mitochondria and GLUT4 N1 - 820 N1 - 19258654 Holloszy, J O Review Poland Journal of physiology and pharmacology : an official journal of the Polish Physiological Society J Physiol Pharmacol. 2008 Dec;59 Suppl 7:5-18. KW - Animals Calcium/metabolism Exercise/*physiology Gene Expression Regulation/physiology Glucose Transporter Type 4/*metabolism Humans Mitochondria/*metabolism Muscle, Skeletal/metabolism Physical Endurance/physiology Signal Transduction/physiology Transcription Factors/metabolism N2 - Endurance exercise-training results in an increase in the size and number of mitochondria in the skeletal muscles that are involved in the exercise. In early studies of this phenomenon, long-term training programs of progressively increasing intensity and duration were used. These studies gave the impression that the adaptive increase in mitochondria is a slow process. Recent advances in the understanding of how mitochondrial biogenesis is regulated, have made it possible to study the mechanisms by which exercise regulates mitochondrial biogenesis. These studies have shown that a single bout of exercise induces a rapid increase in mitochondrial biogenesis that is mediated both by activation and by increased expression of a transcription coactivator, peroxisome proliferator-activated receptor-gamma coactivator 1alpha (PGC-1alpha). PGC-1alpha docks on and coactivates transcription factors that regulate expression of nuclear genes that encode mitochondrial proteins and also of the nuclear gene that encodes mitochondrial transcription factor A (TFAM). TFAM regulates mitochondrial DNA transcription. Thus, PGC-1alpha regulates the coordinated expression of mitochondrial proteins encoded in both nuclear and mitochondrial genes. In addition to an increase in mitochondrial biogenesis, exercise induces an increase in the GLUT4 isoform of the glucose transporter. This increase in GLUT4 occurs in parallel with, and is mediated by, the same signals and some of the same transcription factors as the increase in mitochondrial biogenesis. Two signals generated during exercise, the increase in cytosolic Ca(2+) and the decrease in high energy phosphates, mediate the activation and increased expression of PGC-1alpha. The purpose of this article is to present an overview of what is known regarding these phenomena. AD - Division of Geriatrics and Nutritional Sciences, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA. jhollosz@dom.wustl.edu UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=19258654 ID - 65 ER - TY - JOUR AU - Hopkins, W. G. PY - 2000 TI - Measures of reliability in sports medicine and science SP - 1-15 JF - SM VL - 30 N1 - Measures of reliability in sports medicine and science N1 - 39 ID - 158 ER - TY - JOUR AU - Hopkins, W. G. PY - 2004 TI - Bias in Bland-Altman but not regression validity analyses SP - 42-46 JF - Sportscience VL - 8 N1 - Bias in Bland-Altman but not regression validity analyses N1 - 38 KW - calibration, method comparison, random error, systematic error, standard error of the estimate N2 - An instrument that has been calibrated against a criterion measure with a sample of subjects is sometimes checked against the criterion in a validity study with another sample. In a spreadsheet-based simulation of such calibration and validity studies, a Bland-Altman plot of difference vs mean values for the instrument and criterion shows a systematic proportional bias in the instrument's readings, even though none is present. In contrast, a regression analysis of the criterion vs the instrument shows no bias. The regression analysis also provides complete statistics for recalibrating the instrument, if bias develops or if random error changes since the last calibration. The Bland-Altman analysis of validity should therefore be abandoned in favor of regression. AD - Sport and Recreation, Faculty of Health, Auckland University of Technology, Auckland 1020, New Zealand. Email: will=AT=clear.net.nz UR - http://sportsci.org/jour/04/wghbias.htm ID - 157 ER - TY - JOUR AU - Hopkins, W. G. PY - 2006 TI - Estimating sample size for magnitude-based inferences SP - 63-70 JF - Sportscience VL - 10 N1 - Estimating sample size for magnitude-based inferences N1 - 34 KW - confidence limits, research design, statistical power, Type 1 error, Type 2 error N2 - Sample-size estimation based on the traditional method of statistical significance is not appropriate for a study designed to make an inference about real-world significance, which requires interpretation of magnitude of an outcome. I present here a spreadsheet using two new methods for estimating sample size for such studies, based on acceptable uncertainty defined either by the width of the confidence interval or by error rates for a clinical or practical decision arising from the study. The spreadsheet includes a section for estimating sample size by the traditional method, which requires sample sizes three times greater than those provided by the new methods. The key issues and statistical principles underlying sample-size estimation are outlined in an accompanying slideshow and conference poster. AD - Sport and Recreation, AUT University, Auckland 0627, New Zealand. Email: will=AT=clear.net.nz UR - http://sportsci.org/2006/wghss.htm ID - 150 ER - TY - JOUR AU - Hopkins, W. G. PY - 2006 TI - A spreadsheet for combining outcomes from several subject groups SP - 51-53 JF - Sportscience VL - 10 N1 - A spreadsheet for combining outcomes from several subject groups N1 - 16 AD - Sport and Recreation, AUT University, Auckland 0627, New Zealand. Email: will=AT=clear.net.nz UR - http://sportsci.org/2006/wghcomb.htm ID - 151 ER - TY - JOUR AU - Hopkins, W. G. PY - 2007 TI - A spreadsheet for deriving a confidence interval, mechanistic inference and clinical inference from a p value SP - 16-20 JF - Sportscience VL - 11 N1 - A spreadsheet for deriving a confidence interval, mechanistic inference and clinical inference from a p value N1 - 67 KW - clinical decision, confidence limits, null-hypothesis test, practical importance, statistical significance AD - Sport and Recreation, AUT University, Auckland 0627, New Zealand. Email: will@clear.net.nz UR - http://sportsci.org/2007/wghinf.htm ID - 143 ER - TY - JOUR AU - Hopkins, W. G. PY - 2008 TI - Research designs: choosing and fine-tuning a design for your study SP - 12-21 JF - Sportscience VL - 12 N1 - Research designs: choosing and fine-tuning a design for your study N1 - 75 KW - analysis, bias, case study, confounding, control, intervention, measurement, mediators, moderators, modulators, observational, randomized controlled trial, RCT, single subject N2 - Researchers can design a study to characterize a single instance of a phenomenon or to make an inference about a phenomenon in a population via a sample. Single-subject (or case) studies are justifiable when sampling is difficult or inappropriate. Psychosocial cases aimed at solving a specific problem usually require qualitative methods. Clinical cases are reports of diagnosis or treatment of injury or illness and are usually based on quantitative assessments and qualitative analysis. Non-clinical quantitative cases involve repeated sampling on a single subject and a quantitative inference about the subject generally. Sample-based designs are either observational or interventional, and most are aimed at quantifying a causal effect, in which changes in a predictor variable on average cause changes in a dependent variable. Establishing such causality in observational designs is problematic, owing to difficulties in adjusting for bias in the effect arising from confounders (variables that cause changes in the predictor and dependent). This problem is eliminated in interventions, but the necessary inclusion of a control treatment introduces bias mediated by differences between the groups in administration of treatments, compliance with study requirements, or imbalance in subject characteristics. Use of blinding and randomization at the design stage and inclusion of covariates in the analysis generally lead to trustworthy outcomes by reducing bias in interventions, but observational studies are sometimes the only ethically or logistically possible choice. The observational studies in approximate ascending order of the quality of evidence they provide for causality are case series, cross-sectional studies, case-control studies, and cohort studies. The corresponding approximate order for interventions is pre-post single group, post-only crossover, pre-post crossover, pre-post parallel groups, and post-only parallel groups. Methodological designs are also of interest to researchers; these are special kinds of cross-sectional study aimed at characterizing the validity, diagnostic accuracy, reliability or factor structure of a measure. Finally, reviews are another kind of cross-sectional study in which the “subjects” are study-estimates of an effect and in which the analyst estimates the effect of different settings on the outcome. Each design has particular strengths that offset its weaknesses and make it the most appropriate for a research question. AD - Sport and Recreation, AUT University, Auckland 0627, New Zealand. Email: will@clear.net.nz ID - 141 ER - TY - CHAP AU - Hopkins, W. G. PY - 2009 BT - Methodology in Sports Injury Research CT - Statistics in observational studies CY - Oxford PB - OUP SP - 69-81 N1 - Statistics in observational studies N1 - 76 ID - 145 ER - TY - JOUR AU - Hopkins, W. G. AU - Hawley, J. A. AU - Burke, L. M. PY - 1999 TI - Design and analysis of research on sport performance enhancement SP - 472-485 JF - MSSE VL - 31 N1 - Design and analysis of research on sport performance enhancement N1 - 24 N1 - jour KW - perf, stats, rely ID - 146 ER - TY - JOUR AU - Hopkins, W. G. AU - Marshall, S. W. AU - Batterham, A. M. AU - Hanin, J. PY - 2009 TI - Progressive statistics for studies in sports medicine and exercise science SP - 3-12 JF - Medicine and Science in Sports and Exercise VL - 41 N1 - Progressive statistics for studies in sports medicine and exercise science N1 - 77 ID - 129 ER - TY - JOUR AU - Hopkins, W. G. AU - Marshall, S. W. AU - Quarrie, K. L. AU - Hume, P. A. PY - 2007 TI - Risk factors and risk statistics for sports injuries SP - 208-210 JF - Clinical Journal of Sport Medicine VL - 17 N1 - Risk factors and risk statistics for sports injuries N1 - 31 ID - 154 ER - TY - JOUR AU - Hoppeler, H. AU - Klossner, S. AU - Fluck, M. PY - 2007 TI - Gene expression in working skeletal muscle SP - 245-54 JF - Adv Exp Med Biol VL - 618 N1 - Gene expression in working skeletal muscle N1 - 918 N1 - 18269202 Hoppeler, Hans Klossner, Stephan Fluck, Martin Research Support, Non-U.S. Gov't Review United States Advances in experimental medicine and biology Adv Exp Med Biol. 2007;618:245-54. KW - Exercise/*physiology Humans Muscle, Skeletal/metabolism/*physiology Physical Exertion Signal Transduction Transcription Factors *Transcription, Genetic N2 - A number of molecular tools enable us to study the mechanisms of muscle plasticity. Ideally, this research is conducted in view of the structural and functional consequences of the exercise-induced changes in gene expression. Muscle cells are able to detect mechanical, metabolic, neuronal and hormonal signals which are transduced over multiple pathways to the muscle genome. Exercise activates many signaling cascades--the individual characteristic of the stress leading to a specific response of a network of signaling pathways. Signaling typically results in the transcription of multiple early genes among those of the well known for and jun family, as well as many other transcription factors. These bind to the promoter regions of downstream genes initiating the structural response of muscle tissue. While signaling is a matter of minutes, early genes are activated over hours leading to a second wave of transcript adjustments of structure genes that can then be effective over days. Repeated exercise sessions thus lead to a concerted accretion of mRNAs which upon translation results in a corresponding protein accretion. On the structural level, the protein accretion manifests itself for instance as an increase in mitochondrial volume upon endurance training or an increase in myofibrillar proteins upon strength training. A single exercise stimulus carries a molecular signature which is typical both for the type of stimulus (i.e. endurance vs. strength) as well as the actual condition of muscle tissue (i.e. untrained vs. trained). Likewise, it is clearly possible to distinguish a molecular signature of an expressional adaptation when hypoxic stress is added to a regular endurance exercise protocol in well-trained endurance athletes. It therefore seems feasible to use molecular tools to judge the properties of an exercise stimulus much earlier and at a finer level than is possible with conventional functional or structural techniques. AD - Department of Anatomy, University of Bern, Bern, Switzerland. hoppeler@ana.unibe.ch UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=18269202 ID - 82 ER - TY - JOUR AU - Ingham, S. A. AU - Carter, H. AU - Whyte, G. P. AU - Doust, J. H. PY - 2008 TI - Physiological and performance effects of low- versus mixed-intensity rowing training SP - 579-84 N1 - Mar JF - Med Sci Sports Exerc VL - 40 IS - 3 N1 - Physiological and performance effects of low- versus mixed-intensity rowing training N1 - 913 N1 - 18379224 Ingham, Stephen A Carter, Helen Whyte, Gregory P Doust, Jonathan H Randomized Controlled Trial Research Support, Non-U.S. Gov't United States Medicine and science in sports and exercise Med Sci Sports Exerc. 2008 Mar;40(3):579-84. KW - Adolescent Adult Exercise Test/*methods Exercise Tolerance/*physiology Humans Lactic Acid/blood Male Oxygen Consumption/physiology Physical Exertion/*physiology Pulmonary Gas Exchange Sports/*physiology N2 - PURPOSE: To examine the impact of low-intensity and a mixture of low- and high-intensity training on physiological and performance responses in rowing. METHODS: Eighteen experienced rowers undertook a 12-wk program of 100% < or = lactate threshold (LT) training (LOW) or 70% training at < or = LT and 30% at halfway (50%Delta) between the V O2 at LT and V O2peak (MIX). Responses were assessed before and after training by a progressive exercise test to exhaustion; multiple "square-wave" rest-to-exercise transitions of 6-min duration at 50%Delta; and a maximal 2000-m ergometer time trial. RESULTS: Improvements (P < 0.001) in 2000-m ergometer performance and V O2peak occurred independently of groups (P = 0.8 and 0.42, respectively). LOW improved the power at LT (23.5 +/- 12.2 vs 5.1 +/- 5.0 W, P = 0.013) and power at a [blood lactate] of 4 mM (32.3 +/- 6.9 vs 13.1 +/- 3.7 W, P = 0.03) compared with MIX. The time constant and gain of the primary component were unchanged with training, whereas the gain of the V O2 slow component was reduced with training, but independently of group. CONCLUSIONS: Both LOW and MIX training programs improved performance and V O2peak by the same magnitude, whereas LOW attenuated the blood lactate response to a given exercise intensity more so than MIX. AD - English Institute of Sport, Loughborough University, Loughborough, Leicestershire, UK. steve.ingham@eis2win.co.uk UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=18379224 ID - 36 ER - TY - JOUR AU - Irwig, L. AU - Tosteson, A. N. A. AU - Gatsonis, C. AU - Lau, J. AU - Colditz, G. AU - Chalmers, T. C. AU - Mosteller, F. PY - 1994 TI - Guidelines for meta-analyses evaluating diagnostic tests SP - 667-676 JF - Annals of Internal Medicine VL - 120 IS - 8 N1 - Guidelines for meta-analyses evaluating diagnostic tests N1 - 59 N1 - Am Coll Physicians ID - 140 ER - TY - JOUR AU - Ishibashi, T. AU - Dakin, K. A. AU - Stevens, B. AU - Lee, P. R. AU - Kozlov, S. V. AU - Stewart, C. L. AU - Fields, R. D. PY - 2006 TI - Astrocytes promote myelination in response to electrical impulses SP - 823-32 N1 - Mar 16 JF - Neuron VL - 49 IS - 6 N1 - Astrocytes promote myelination in response to electrical impulses N1 - 1022 N1 - 16543131 Ishibashi, Tomoko Dakin, Kelly A Stevens, Beth Lee, Philip R Kozlov, Serguei V Stewart, Colin L Fields, R Douglas Z01 HD000713-11/HD/NICHD NIH HHS/United States Comparative Study Research Support, N.I.H., Extramural Research Support, N.I.H., Intramural United States Neuron Neuron. 2006 Mar 16;49(6):823-32. KW - Action Potentials/physiology/radiation effects Adenosine/pharmacology Adenosine Triphosphate/analogs & derivatives/metabolism/pharmacology Adenosine-5'-(N-ethylcarboxamide)/pharmacology Anesthetics, Local/pharmacology Animals Antibodies/pharmacology Astrocytes/physiology/*radiation effects Axons/drug effects/metabolism/radiation effects Azo Compounds/diagnostic use Blotting, Western/methods Cell Communication/drug effects/*physiology/radiation effects Cell Count/methods Cells, Cultured Cerebral Cortex/cytology Coculture Techniques/methods DNA-Binding Proteins/metabolism Dose-Response Relationship, Drug Drosophila Proteins/metabolism Drug Interactions Electric Stimulation/*methods Embryo, Mammalian Enzyme-Linked Immunosorbent Assay/methods Ganglia, Spinal/cytology Gene Expression/drug effects Immunohistochemistry/methods Interleukin-6/immunology/metabolism Leukemia Inhibitory Factor Mice Models, Biological Myelin Basic Proteins/metabolism Myelin Proteins/*metabolism Myelin-Associated Glycoprotein/metabolism Neurons/cytology/drug effects/physiology O Antigens/metabolism Oligodendroglia/*physiology RNA, Messenger/biosynthesis Rats Reverse Transcriptase Polymerase Chain Reaction/methods Stem Cells Tetrodotoxin/pharmacology Thionucleotides/pharmacology Time Factors N2 - Myelin, the insulating layers of membrane wrapped around axons by oligodendrocytes, is essential for normal impulse conduction. It forms during late stages of fetal development but continues into early adult life. Myelination correlates with cognitive development and can be regulated by impulse activity through unknown molecular mechanisms. Astrocytes do not form myelin, but these nonneuronal cells can promote myelination in ways that are not understood. Here, we identify a link between myelination, astrocytes, and electrical impulse activity in axons that is mediated by the cytokine leukemia inhibitory factor (LIF). These findings show that LIF is released by astrocytes in response to ATP liberated from axons firing action potentials, and LIF promotes myelination by mature oligodendrocytes. This activity-dependent mechanism promoting myelination could regulate myelination according to functional activity or environmental experience and may offer new approaches to treating demyelinating diseases. AD - Nervous System Development and Plasticity Section, National Institute of Child Health and Human Development, Bethesda, Maryland 20892, USA. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16543131 ID - 58 ER - TY - JOUR AU - Jaeschke, R. AU - Guyatt, G. AU - Sackett, D. L. PY - 1994 TI - Users’guides to the medical literature. III. How to use an article about a diagnostic test. A. Are the results of the study valid? SP - 389-91 JF - JAMA VL - 271 IS - 5 N1 - Users’guides to the medical literature. III. How to use an article about a diagnostic test. A. Are the results of the study valid? N1 - 60 ID - 147 ER - TY - JOUR AU - Joseph, A. M. AU - Pilegaard, H. AU - Litvintsev, A. AU - Leick, L. AU - Hood, D. A. PY - 2006 TI - Control of gene expression and mitochondrial biogenesis in the muscular adaptation to endurance exercise SP - 13-29 JF - Essays Biochem VL - 42 N1 - Control of gene expression and mitochondrial biogenesis in the muscular adaptation to endurance exercise N1 - 724 N1 - 17144877 Joseph, Anna-Maria Pilegaard, Henriette Litvintsev, Anastassia Leick, Lotte Hood, David A Review England Essays in biochemistry Essays Biochem. 2006;42:13-29. KW - Adaptation, Physiological Adipose Tissue, Brown/metabolism Animals DNA, Mitochondrial/genetics/metabolism Exercise/*physiology Gene Expression Regulation Heat-Shock Proteins/metabolism Humans Insulin Resistance Mitochondria, Muscle/metabolism Models, Biological Muscle, Skeletal/metabolism/*physiology Myocardium/metabolism Physical Endurance/physiology Physical Exertion/physiology Protein Transport Signal Transduction Transcription Factors/metabolism N2 - Every time a bout of exercise is performed, a change in gene expression occurs within the contracting muscle. Over the course of many repeated bouts of exercise (i.e. training), the cumulative effects of these alterations lead to a change in muscle phenotype. One of the most prominent of these adaptations is an increase in mitochondrial content, which confers a greater resistance to muscle fatigue. This essay reviews current knowledge on the regulation of exercise-induced mitochondrial biogenesis at the molecular level. The major steps involved include, (i) transcriptional regulation of nuclear-encoded genes encoding mitochondrial proteins by the coactivator peroxisome-proliferator-activated receptor g coactivator-1, (ii) control of mitochondrial DNA gene expression by the transcription factor Tfam, (iii) mitochondrial fission and fusion mechanisms, and (iv) import of nuclear-derived gene products into the mitochondrion via the protein import machinery. It is now known that exercise can modify the rates of several of these steps, leading to mitochondrial biogenesis. An understanding of how exercise can produce this effect could help us decide whether exercise is beneficial for patients suffering from mitochondrial disorders, as well as a variety of metabolic diseases. AD - Department of Biology, York University, Toronto, Ontario, Canada, M3J 1P3. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=17144877 ID - 81 ER - TY - JOUR AU - Kamo, M. PY - 2002 TI - Discharge behavior of motor units in knee extensors during the initial stage of constant-force isometric contraction at low force level SP - 375-81 N1 - Mar JF - Eur J Appl Physiol VL - 86 IS - 5 N1 - Discharge behavior of motor units in knee extensors during the initial stage of constant-force isometric contraction at low force level N1 - 1025 N1 - 11882921 Kamo, Mifuyu Comparative Study Germany European journal of applied physiology Eur J Appl Physiol. 2002 Mar;86(5):375-81. Epub 2002 Jan 23. KW - Action Potentials/physiology Adult Analysis of Variance Biomechanics Electromyography/methods Female Humans Isometric Contraction/*physiology Knee/*physiology Male Middle Aged Motor Neurons/*physiology Muscle, Skeletal/*physiology Recruitment, Neurophysiological/*physiology Reference Values Reproducibility of Results N2 - To elucidate the strategy of the activity of motor units (MUs) to maintain a constant-force isometric contraction, I examined the behavior of MUs in knee extensor muscles [(vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF)] during a sustained contraction at 5% of maximal voluntary contraction for 5 min. In all cases, the spike interval exhibited an elongating trend, and two discharge patterns were observed, continuous discharge and decruitment. In continuous-discharge MUs, the trend slope was steep immediately after the onset of constant force (steep phase), and then became gentle (gentle phase). Decruitments were observed frequently during each phase, and additional MU recruitment was observed throughout the contraction. The mean value of recruitment threshold force did not differ among the extensors. The mean spike interval at the onset of constant-force isometric contractions was shorter in RF than in VL. However, there were no differences in the duration and extent of the elongating trend, decruitment time and recruitment time among the extensors. The electromyogram of the antagonist biceps femoris muscle revealed no compensatory change for extensor activity. These results indicated that at a low force level, the strategy employed by the central nervous system to maintain constant force appears to involve cooperation among elongating trends in the spike interval, decruitment following elongation, and additional MU recruitment in synergistic muscles. AD - Laboratory of Exercise Physiology, Faculty of Physical Education, Japan Women's College of Physical Education, 8-19-1 Kita-Karasuyama, Setagaya-ku 157-8565, Tokyo, Japan. kamo@jwcpe.ac.jp UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11882921 ID - 57 ER - TY - JOUR AU - Lamberts, R P AU - Swart, J AU - Capostagno, B AU - Noakes, T D AU - Lambert, M I PY - 2009 TI - Heart rate recovery as a guide to monitor fatigue and predict changes in performance parameters JF - Scandinavian Journal of Medicine and Science in Sports VL - (in press) N1 - Heart rate recovery as a guide to monitor fatigue and predict changes in performance parameters ID - 31 ER - TY - JOUR AU - Laughlin, M. H. AU - Roseguini, B. PY - 2008 TI - Mechanisms for exercise training-induced increases in skeletal muscle blood flow capacity: differences with interval sprint training versus aerobic endurance training SP - 71-88 N1 - Dec JF - J Physiol Pharmacol VL - 59 Suppl 7 N1 - Mechanisms for exercise training-induced increases in skeletal muscle blood flow capacity: differences with interval sprint training versus aerobic endurance training N1 - 1057 N1 - 19258658 Laughlin, M H Roseguini, B KW - Animals *Exercise Humans Muscle Contraction/physiology Muscle Fibers, Skeletal/metabolism Muscle, Skeletal/*blood supply Physical Education and Training *Physical Endurance Vascular Resistance/physiology N2 - Skeletal muscle blood flow capacity (BFC) is increased by exercise training due to structural vascular remodeling (in the form of angiogenesis of capillaries and remodeling of the arterial tree within skeletal muscle) and/or altered control of vascular resistance. Changes in control can be central or the result of changes in reactivity of arteries and arterioles (due to changes in vascular smooth muscle and/or endothelium). The purpose of this review is to evaluate the relative importance of these mechanisms for increased BFC following interval sprint training (IST) and endurance exercise training (ET). Based on the results discussed herein we conclude that the importance of each of these mechanisms varies throughout muscle tissue due to interactions of muscle fiber-type composition and muscle fiber recruitment patterns during exercise. The distribution of vascular adaptive changes varies with mode of training. For example, IST has been shown to produce the greatest relative increase in contractile activity in fast-twitch, white, skeletal muscle (i.e. white gastrocnemius muscle (Gw) and Gw muscle exhibits the largest increase in oxidative capacity, capillary density, BFC, and changes in vascular cells with IST. In contrast, ET has been shown to produce the greatest relative increase in contractile activity in red gastrocnemius muscle (Gr), and Gr muscle exhibits the largest increase in oxidative capacity, capillary density, and BFC after ET training. Results demonstrate that the increases in BFC are not mediated solely by structural adaptation. Rather, changes in vascular control predominate in Gr and soleus muscle, while increases in arteriolar and capillary density predominate following IST in Gw. Finally, evidence indicates that ET and IST induce non-uniform changes in smooth muscle and endothelium throughout skeletal muscle arteriolar networks. AD - Department of Biomedical Sciences, University of Missouri, Columbia, MO 65211, USA. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=19258658 ID - 63 ER - TY - JOUR AU - Lehmann, M. J. AU - Lormes, W. AU - Opitz-Gress, A. AU - Steinacker, J. M. AU - Netzer, N. AU - Foster, C. AU - Gastmann, U. PY - 1997 TI - Training and overtraining: an overview and experimental results in endurance sports SP - 7-17 N1 - Mar JF - J Sports Med Phys Fitness VL - 37 IS - 1 N1 - Training and overtraining: an overview and experimental results in endurance sports N1 - 1058 N1 - 9190120 Lehmann, M J Lormes, W Opitz-Gress, A Steinacker, J M Netzer, N Foster, C Gastmann, U Research Support, Non-U.S. Gov't Review Italy The Journal of sports medicine and physical fitness J Sports Med Phys Fitness. 1997 Mar;37(1):7-17. KW - Adrenal Glands/physiopathology Adrenocorticotropic Hormone/physiology Affect/physiology Amino Acids/metabolism Autonomic Nervous System/physiopathology Burnout, Professional/etiology Catecholamines/physiology Fatigue/etiology Glycogen/metabolism Growth Hormone-Releasing Hormone/physiology Heat-Shock Proteins/biosynthesis Human Growth Hormone/secretion Humans Hydrocortisone/secretion Infection/etiology Motor Neurons/physiology Neuromuscular Junction/physiopathology Neurosecretory Systems/physiopathology Physical Endurance/*physiology Pituitary Gland/physiopathology Psychomotor Performance/physiology Receptors, Adrenergic, beta/physiology Reproduction/physiology Risk Factors Sports/*physiology Stress, Physiological/physiopathology Stress, Psychological/physiopathology Sympathetic Nervous System/physiopathology Syndrome N2 - Overtraining can be defined as "training-competition > > recovery imbalance", that is assumed to result in glycogen deficit, catabolic > anabolic imbalance, neuroendocrine imbalance, amino acid imbalance, and autonomic imbalance. Additional non-training stress factors and monotony of training exacerbate the risk of a resulting overtraining syndrome. Short-term overtraining called overreaching which can be seen as a normal part of athletic training, must be distinguished from long-term overtraining that can lead to a state described as burnout, staleness or overtraining syndrome. Persistent performance incompetence, persistent high fatigue ratings, altered mood state, increased rate of infections, and suppressed reproductive function have been described as key findings in overtraining syndrome. An increased risk of overtraining syndrome may be expected around 3 weeks of intensified/prolonged endurance training at a high training load level. Heavy training loads may apparently be tolerated for extensive periods of time if athletes take a rest day every week and use alternating hard and easy days of training. Persistent performance incompetence and high fatigue ratings may depend on impaired or inhibited transmission of ergotropic (catabolic) signals to target organs, such as: (I) decreased neuromuscular excitability, (II) inhibition of alpha-motoneuron activity (hypothetic), (III) decreased adrenal sensitivity to ACTH (cortisol release) and increased pituitary sensitivity to GHRH (GH release) resulting in a counter-regulatory shift to a more anabolic endocrine responsibility, (IV) decreased beta-adrenoreceptor density (sensitivity to catecholamines), (V) decreased intrinsic sympathetic activity, and (VI) intracellular protective mechanisms such as increased synthesis of heat-shock proteins (HSP 70) represent a complex strategy against an overload-dependent cellular damage. AD - Department of Sports Medicine, University Medical Hospital Ulm. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9190120 ID - 60 ER - TY - JOUR AU - Lindsay, F. H. AU - Hawley, J. A. AU - Myburgh, K. H. AU - Schomer, H. H. AU - Noakes, T. D. AU - Dennis, S. C. PY - 1996 TI - Improved athletic performance in highly trained cyclists after interval training SP - 1427-34 N1 - Nov JF - Med Sci Sports Exerc VL - 28 IS - 11 N1 - Improved athletic performance in highly trained cyclists after interval training N1 - 70 N1 - 8933495 Lindsay, F H Hawley, J A Myburgh, K H Schomer, H H Noakes, T D Dennis, S C Research Support, Non-U.S. Gov't United states Medicine and science in sports and exercise Med Sci Sports Exerc. 1996 Nov;28(11):1427-34. KW - Adult Bicycling/*physiology Heart Rate Humans Male Task Performance and Analysis N2 - This study determined whether a 4-wk high-intensity interval training program (HIT) would improve the 40-km time trial performances (TT40) of 8 competitive cyclists (peak O2 uptake 5.2 +/- 0.4 I.min-1) with a background of moderate-intensity endurance training (BASE). Before intervention, all cyclists were tested on at least three separate occasions to ensure that their baseline performances were stable. In these tests, peak sustained power output (PPO) was measured during a progressive exercise test, muscular resistance to fatigue was determined during a timed ride to exhaustion at 150% of PPO (TF150), and a TT40 was performed on a cycle-simulator. The coefficient of variation for all baseline tests was < 1.7 +/- 1.3% (mean +/- SD). Cyclists then replaced 15 +/- 2% of their approximately 300 km.wk-1 BASE training with HIT, which took place on 6 d and consisted of six to eight 5-min repetitions at 80% of PPO, with 60-s recovery between work bouts. HIT significantly improved TT40 (56.4 +/- 3.6 vs 54.4 +/- 3.2 min; P < 0.0001), PPO (416 +/- 32 vs 434 +/- 34 W; P < 0.01) and TF150 (60.5 +/- 9.3 vs 72.5 +/- 7.6 s; P < 0.01). The faster TT40 was due to a significant increase in both the cyclists' absolute (301 +/- 42 vs 326 +/- 43 W; P < 0.0001) and relative (72.1 +/- 5.6 vs 75.0 +/- 6.8% of PPO; P < 0.05) power output after HIT. These results indicate that a 4-wk program of HIT increased the PPO and fatigue resistance of competitive cyclists and improved their 40-km time trial performances. AD - Bioenergetics of Exercise Research Unit, Medical Research Council, Observatory, South Africa. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8933495 ID - 95 ER - TY - JOUR AU - Lucia, A. AU - Hoyos, J. AU - Carvajal, A. AU - Chicharro, J. L. PY - 1999 TI - Heart rate response to professional road cycling: the Tour de France SP - 167-72 N1 - Apr JF - Int J Sports Med VL - 20 IS - 3 N1 - Heart rate response to professional road cycling: the Tour de France N1 - 676 N1 - 10333093 Lucia, A Hoyos, J Carvajal, A Chicharro, J L Germany International journal of sports medicine Int J Sports Med. 1999 Apr;20(3):167-72. KW - Adult Bicycling/*physiology Exercise Test Heart Rate/*physiology Humans Male Oxygen Consumption Physical Endurance/*physiology Respiration N2 - The aim of the present investigation was to evaluate the heart rate response of 8 professional cyclists (26+/-3 yr; 68.9+/-5.2 kg; V02max: 74.0+/-5.8 ml x kg(-1) x min(-1)) during the 3-week Tour de France as an indicator of exercise intensity. Subjects wore a heart rate telemeter during 22 competition stages and recorded data were analysed using computer software. Two reference heart rates (corresponding to the first and second ventilatory thresholds or VT1 and VT2) were used to establish three levels of exercise intensity defined as phases I (VT2) is substantially lower than that of light, aerobic exercise (RCP). Total volume and intensity were integrated as a single variable. The score for volume x intensity in each phase was computed by multiplying the accumulated duration in this phase by a multiplier for this particular phase. The total score for Tour and Vuelta was obtained by summating the results of the three phases. RESULTS: The total loads (volume x intensity) did not significantly differ between the two races (P > 0.05), despite a significantly longer total exercise time of the Tour (P < 0.05) (5552 +/- 176 vs 5086 +/- 290 min). CONCLUSION: The physiological loads imposed on cyclists' bodies do not differ between the Tour and Vuelta, despite the longer duration of daily stages in the former race. AD - Faculty of Physical Activity and Sports, European University of Madrid, Madrid, Spain. alejandro.lucia@mrfs.cisa.uem.es UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12750600 ID - 84 ER - TY - JOUR AU - MacDougall, D. AU - Sale, D. PY - 1981 TI - Continuous vs. interval training: a review for the athlete and the coach SP - 93-7 N1 - Jun JF - Can J Appl Sport Sci VL - 6 IS - 2 N1 - Continuous vs. interval training: a review for the athlete and the coach N1 - 87 N1 - 7016358 MacDougall, D Sale, D Review Canada Canadian journal of applied sport sciences. Journal canadien des sciences appliquees au sport Can J Appl Sport Sci. 1981 Jun;6(2):93-7. KW - Anaerobiosis Heart/physiology Humans Muscles/metabolism Oxygen Consumption Physical Education and Training/*methods Physical Exertion *Sports Stroke Volume N2 - Both interval and continuous training are necessary in order to maximize the endurance athlete's potential for competition. Continuous submaximal training exerts its greatest effect upon the oxygen transport system of the body, while high intensity endurance-interval training exerts its greatest effect on the structural and biochemical properties of the muscle. The physiological basis for both forms of training is discussed and recommendations are made for year-round training and training to elevate the anaerobic threshold. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=7016358 ID - 108 ER - TY - JOUR AU - Marcuello, A. AU - Gonzalez-Alonso, J. AU - Calbet, J. A. AU - Damsgaard, R. AU - Lopez-Perez, M. J. AU - Diez-Sanchez, C. PY - 2005 TI - Skeletal muscle mitochondrial DNA content in exercising humans SP - 1372-7 N1 - Oct JF - J Appl Physiol VL - 99 IS - 4 N1 - Skeletal muscle mitochondrial DNA content in exercising humans N1 - 924 N1 - 15932963 Marcuello, A Gonzalez-Alonso, J Calbet, J A L Damsgaard, R Lopez-Perez, M J Diez-Sanchez, C Research Support, Non-U.S. Gov't United States Journal of applied physiology (Bethesda, Md. : 1985) J Appl Physiol. 2005 Oct;99(4):1372-7. Epub 2005 Jun 2. KW - Adult Bicycling/physiology Cell Nucleus/metabolism DNA/antagonists & inhibitors/metabolism DNA, Mitochondrial/antagonists & inhibitors/*metabolism Exercise/*physiology Female Humans Male Oxygen Consumption Quadriceps Muscle/*metabolism Time Factors N2 - Several weeks of intense endurance training enhances mitochondrial biogenesis in humans. Whether a single bout of exercise alters skeletal muscle mitochondrial DNA (mtDNA) content remains unexplored. Double-stranded mtDNA, estimated by slot-blot hybridization and real time PCR and expressed as mtDNA-to-nuclear DNA ratio (mtDNA/nDNA) was obtained from the vastus lateralis muscle of healthy human subjects to investigate whether skeletal muscle mtDNA changes during fatiguing and nonfatiguing prolonged moderate intensity [2.0-2.5 h; approximately 60% maximal oxygen consumption (Vo(2 max))] and short repeated high-intensity exercise (5-8 min; approximately 110% Vo(2 max)). In control resting and light exercise (2 h; approximately 25% Vo(2 max)) studies, mtDNA/nDNA did not change. Conversely, mtDNA/nDNA declined after prolonged fatiguing exercise (0.863 +/- 0.061 vs. 1.101 +/- 0.067 at baseline; n = 14; P = 0.005), remained lower after 24 h of recovery, and was restored after 1 wk. After nonfatiguing prolonged exercise, mtDNA/nDNA tended to decline (n = 10; P = 0.083) but was reduced after three repeated high-intensity exercise bouts (0.900 +/- 0.049 vs. 1.067 +/- 0.071 at baseline; n = 7; P = 0.013). Our findings indicate that prolonged and short repeated intense exercise can lead to significant reductions in human skeletal muscle mtDNA content, which might function as a signal stimulating mitochondrial biogenesis with exercise training. AD - Department of Biochemistry, Molecular and Cell Biology, University of Zaragoza, Spain. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15932963 ID - 80 ER - TY - CHAP AU - Marino, F E PY - 2008 BT - Thermoregulation and Human Performance ED - Marino, F E CT - The evolutionary basis of thermoregulation and exercise performance CY - Basel PB - Karger SP - 1-13 N1 - The evolutionary basis of thermoregulation and exercise performance ID - 15 ER - TY - JOUR AU - McConell, G. K. AU - Lee-Young, R. S. AU - Chen, Z. P. AU - Stepto, N. K. AU - Huynh, N. N. AU - Stephens, T. J. AU - Canny, B. J. AU - Kemp, B. E. PY - 2005 TI - Short-term exercise training in humans reduces AMPK signalling during prolonged exercise independent of muscle glycogen SP - 665-76 N1 - Oct 15 JF - J Physiol VL - 568 IS - Pt 2 N1 - Short-term exercise training in humans reduces AMPK signalling during prolonged exercise independent of muscle glycogen N1 - 1410 N1 - 16051629 McConell, Glenn K Lee-Young, Robert S Chen, Zhi-Ping Stepto, Nigel K Huynh, Ngan N Stephens, Terry J Canny, Benedict J Kemp, Bruce E Clinical Trial Research Support, Non-U.S. Gov't England The Journal of physiology J Physiol. 2005 Oct 15;568(Pt 2):665-76. Epub 2005 Jul 28. KW - AMP-Activated Protein Kinases Acetyl-CoA Carboxylase/metabolism Blood Glucose Dietary Carbohydrates/administration & dosage Exercise/*physiology Glucose/metabolism Glycogen/metabolism Humans Lipid Metabolism Male Multienzyme Complexes/*metabolism Muscle, Skeletal/*metabolism Phosphorylation Protein-Serine-Threonine Kinases/*metabolism Serine/metabolism Signal Transduction/*physiology N2 - We examined the effect of short-term exercise training on skeletal muscle AMP-activated protein kinase (AMPK) signalling and muscle metabolism during prolonged exercise in humans. Eight sedentary males completed 120 min of cycling at 66 +/- 1% , then exercise trained for 10 days, before repeating the exercise bout at the same absolute workload. Participants rested for 72 h before each trial while ingesting a high carbohydrate diet (HCHO). Exercise training significantly (P < 0.05) attenuated exercise-induced increases in skeletal muscle free AMP: ATP ratio and glucose disposal and increased fat oxidation. Exercise training abolished the 9-fold increase in AMPK alpha2 activity observed during pretraining exercise. Since training increased muscle glycogen content by 93 +/- 12% (P < 0.01), we conducted a second experiment in seven sedentary male participants where muscle glycogen content was essentially matched pre- and post-training by exercise and a low CHO diet (LCHO; post-training muscle glycogen 52 +/- 7% less than in HCHO, P < 0.001). Despite the difference in muscle glycogen levels in the two studies we obtained very similar results. In both studies the increase in ACCbeta Ser(221) phosphorylation was reduced during exercise after training. In conclusion, there is little activation of AMPK signalling during prolonged exercise following short-term exercise training suggesting that other factors are important in the regulation of glucose disposal and fat oxidation under these circumstances. It appears that muscle glycogen is not an important regulator of AMPK activation during exercise in humans when exercise is begun with normal or high muscle glycogen levels. AD - Department of Physiology, University of Melbourne, Parkville, Victoria, Australia. mcconell@unimelb.edu.au UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16051629 ID - 76 ER - TY - JOUR AU - McPhee, J. S. AU - Williams, A. G. AU - Stewart, C. AU - Baar, K. AU - Schindler, J. P. AU - Aldred, S. AU - Maffulli, N. AU - Sargeant, A. J. AU - Jones, D. A. PY - 2009 TI - The training stimulus experienced by the leg muscles during cycling in humans SP - 684-94 N1 - Jun JF - Exp Physiol VL - 94 IS - 6 N1 - The training stimulus experienced by the leg muscles during cycling in humans N1 - 917 N1 - 19218358 McPhee, Jamie S Williams, Alun G Stewart, Claire Baar, Keith Schindler, Joaquin Perez Aldred, Sarah Maffulli, Nicola Sargeant, Anthony J Jones, David A England Experimental physiology Exp Physiol. 2009 Jun;94(6):684-94. Epub 2009 Feb 13. KW - Adaptation, Physiological Adolescent Adult Aerobiosis Bicycling/*physiology Exercise Test Female Humans Leg Lipids/blood Muscle Proteins/metabolism Oxygen Consumption Physical Endurance/*physiology Quadriceps Muscle/anatomy & histology/*physiology Young Adult N2 - Considerable variability exists between people in their health- and performance-related adaptations to conventional endurance training. We hypothesized that some of this variability might be due to differences in the training stimulus received by the working muscles. In 71 young sedentary women we observed large variations in the ratio of one-leg cycling muscle aerobic capacity (V(O2peak)) to two-leg cycling whole-body maximal oxygen uptake (V(O2max); Ratio(1:2); range 0.58-0.96). The variability in Ratio(1:2) was primarily due to differences between people in one-leg V(O2peak) (r = 0.71, P < 0.0005) and was not related to two-leg V(O2max) (r = 0.15, P = 0.209). Magnetic resonance imaging (n = 30) and muscle biopsy sampling (n = 20) revealed that one-leg V(O2peak) was mainly determined by muscle volume (r = 0.73, P < 0.0005) rather than muscle fibre type or oxidative capacity. A high one-leg V(O2peak) was associated with favourable lipoprotein profiles (P = 0.033, n = 24) but this was not the case for two-leg V(O2max). Calculations based on these data suggest that conventional two-leg exercise at 70% V(O2max) requires subjects with the lowest Ratio(1:2) to work their legs at 60% of single-leg V(O2peak), whilst those with the highest Ratio(1:2) work their legs at only 36% of maximum. It was concluded that endurance training carried out according to current guidelines will result in highly variable training stimuli for the leg muscles and variable magnitudes of adaptation. These conclusions have implications for the prescription of exercise to improve health and for investigations into the genetic basis of muscle adaptations. AD - Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, Manchester, UK. j.s.mcphee@mmu.ac.uk UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=19218358 ID - 79 ER - TY - JOUR AU - Memmert, Daniel AU - Perl, Jürgen PY - 2009 TI - Analysis and simulation of creativity learning by means of artificial neural networks SP - 263-282 JF - Human Movement Science VL - 28 IS - 2 N1 - Analysis and simulation of creativity learning by means of artificial neural networks N1 - 0167-9457 doi: DOI: 10.1016/j.humov.2008.07.006 KW - Soft-modelling Process orientation Pattern recognition Divergent thinking Team sport UR - http://science-direct.com/science/article/B6V8T-4V6YSTS-1/2/eab18d6682b998e26d084e78e7b7e895 ID - 12 ER - TY - JOUR AU - Moher, D. AU - Cook, D. J. AU - Eastwood, S. PY - 1999 TI - Improving the quality of reports of meta-analyses of randomised controlled trials SP - 1896-1900 JF - Lancet VL - 354 N1 - Improving the quality of reports of meta-analyses of randomised controlled trials N1 - 51 ID - 138 ER - TY - JOUR AU - Moher, D. AU - Schulz, K. F. AU - Altman, D. G. PY - 2001 TI - The CONSORT statement: revised recommendations for improving the quality of reports of parallel group randomized trials SP - 657-62 JF - Ann Intern Med VL - 134 N1 - The CONSORT statement: revised recommendations for improving the quality of reports of parallel group randomized trials N1 - 33 ID - 133 ER - TY - BOOK AU - Mosso, A PY - 1915 BT - Fatigue CY - London PB - George Allen & Unwin N1 - Fatigue ID - 14 ER - TY - JOUR AU - Mujika, I. AU - Chatard, J. C. AU - Busso, T. AU - Geyssant, A. AU - Barale, F. AU - Lacoste, L. PY - 1995 TI - Effects of training on performance in competitive swimming SP - 395-406 N1 - Dec JF - Can J Appl Physiol VL - 20 IS - 4 N1 - Effects of training on performance in competitive swimming N1 - 1406 N1 - 8563672 Mujika, I Chatard, J C Busso, T Geyssant, A Barale, F Lacoste, L Research Support, Non-U.S. Gov't United states Canadian journal of applied physiology = Revue canadienne de physiologie appliquee Can J Appl Physiol. 1995 Dec;20(4):395-406. KW - Adaptation, Physiological Adult Exercise/physiology Female Follow-Up Studies Humans Lactates/blood Male Motor Skills Muscle Contraction Physical Education and Training *Psychomotor Performance Swimming/*education/*physiology N2 - The relationships between the mean intensity of a training season, training volume and frequency, and the variations in performance were studied in a group of 18 elite swimmers. Additionally, differences between the swimmers who improved their personal record of the previous year during the follow-up training season (GIR, n = 8) and those who did not (GNI, n = 10) were investigated. The improvement in performance during the follow-up season was significantly correlated with the mean intensity of the training season (r = 0.69, p < 0.01), but not with training volume or frequency. The performance improvement during the follow-up season was negatively related to the initial performance level (r = 0.90, p < 0.01). The decline in performance during detraining from the previous year was less for the GIR than for the GNI (6.21 +/- 2.30% vs. 9.79 +/- 2.18%, p < 0.01). The present findings suggest that training intensity is the key factor in performance improvement in a group of elite swimmers. Factors such as previous detraining and initial performance level could jeopardize success in spite of a good adaptation to training. AD - Laboratoire de Physiologie, Universite Jean Monnet, Faculte de Medecine, Saint-Etienne, France. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8563672 ID - 54 ER - TY - JOUR AU - Noakes, T D AU - Marino, F E PY - 2009 TI - Point: maximal oxygen uptake is limited by a central nervous system governor SP - 338-339 JF - Journal of Applied Physiology VL - 106 N1 - Point: maximal oxygen uptake is limited by a central nervous system governor ID - 1 ER - TY - JOUR AU - Noakes, T. D. AU - Marino, F. E. PY - 2009 TI - Last word on Point:Counterpoint: maximal oxygen uptake is/is not limited by a central nervous system governor SP - 347 JF - Journal of Applied Physiology VL - 106 N1 - Last word on Point:Counterpoint: maximal oxygen uptake is/is not limited by a central nervous system governor ID - 17 ER - TY - JOUR AU - Nordsborg, N. AU - Bangsbo, J. AU - Pilegaard, H. PY - 2003 TI - Effect of high-intensity training on exercise-induced gene expression specific to ion homeostasis and metabolism SP - 1201-6 N1 - Sep JF - J Appl Physiol VL - 95 IS - 3 N1 - Effect of high-intensity training on exercise-induced gene expression specific to ion homeostasis and metabolism N1 - 765 N1 - 12766179 Nordsborg, Nikolai Bangsbo, Jens Pilegaard, Henriette United States Journal of applied physiology (Bethesda, Md. : 1985) J Appl Physiol. 2003 Sep;95(3):1201-6. Epub 2003 May 23. KW - ATP-Binding Cassette Transporters Adult DNA Primers Exercise/*physiology Gene Expression Regulation/genetics/*physiology Homeostasis/*genetics Humans Ions/metabolism Male Muscle, Skeletal/cytology/metabolism/physiology Phosphofructokinases/biosynthesis/genetics Physical Fitness/*physiology Potassium Channels/biosynthesis/genetics Potassium Channels, Inwardly Rectifying RNA, Messenger/biosynthesis Reverse Transcriptase Polymerase Chain Reaction Ribonuclease H/biosynthesis/genetics Sodium-Potassium-Exchanging ATPase/metabolism N2 - Changes in gene expression during recovery from high-intensity, intermittent, one-legged exercise were studied before and after 5.5 wk of training. Genes related to metabolism, as well as Na+, K+, and pH homeostasis, were selected for analyses. After the same work was performed before and after the training period, several muscle biopsies were obtained from vastus lateralis muscle. In the untrained state, the Na+-K+-ATPase alpha1-subunit mRNA level was approximately threefold higher (P < 0.01) at 0, 1, and 3 h after exercise, relative to the preexercise resting level. After 3-5 h of recovery in the untrained state, pyruvate dehydrogenase kinase 4 and hexokinase II mRNA levels were elevated 13-fold (P < 0.001) and 6-fold (P < 0.01), respectively. However, after the training period, only pyruvate dehydrogenase kinase 4 mRNA levels were elevated (P < 0.05) during the recovery period. No changes in resting mRNA levels were observed as a result of training. In conclusion, cellular adaptations to high-intensity exercise training may, in part, be induced by transcriptional regulation. After training, the transcriptional response to an exercise bout at a given workload is diminished. AD - Institute of Exercise and Sports Sciences, August Krogh Institute, 2100 Copenhagen, Denmark. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12766179 ID - 77 ER - TY - JOUR AU - Ojuka, E. O. PY - 2004 TI - Role of calcium and AMP kinase in the regulation of mitochondrial biogenesis and GLUT4 levels in muscle SP - 275-8 N1 - May JF - Proc Nutr Soc VL - 63 IS - 2 N1 - Role of calcium and AMP kinase in the regulation of mitochondrial biogenesis and GLUT4 levels in muscle N1 - 1056 N1 - 15294043 Ojuka, Edward O Review England The Proceedings of the Nutrition Society Proc Nutr Soc. 2004 May;63(2):275-8. KW - Adaptation, Physiological Adenylate Kinase/metabolism/*physiology Calcium/metabolism/*physiology Calcium-Calmodulin-Dependent Protein Kinases/*metabolism Glucose Transporter Type 4 Humans Mitochondria, Muscle/*enzymology/metabolism Monosaccharide Transport Proteins/metabolism Muscle Contraction/*physiology Muscle Proteins/metabolism Muscle, Skeletal/cytology/*enzymology N2 - Contractile activity induces mitochondrial biogenesis and increases glucose transport capacity in muscle. There has been much research on the mechanisms responsible for these adaptations. The present paper reviews the evidence, which indicates that the decrease in the levels of high-energy phosphates, leading to activation of AMP kinase (AMPK), and the increase in cytosolic Ca(2+), which activates Ca(2+)/calmodulin-dependent protein kinase (CAMK), are signals that initiate these adaptative responses. Although the events downstream of AMPK and CAMK have not been well characterized, these events lead to activation of various transcription factors, including: nuclear respiratory factors (NRF) 1 and 2, which cause increased expression of proteins of the respiratory chain; PPAR-alpha, which up regulates the levels of enzymes of beta oxidation; mitochondrial transcription factor A, which activates expression of the mitochondrial genome; myocyte-enhancing factor 2A, the transcription factor that regulates GLUT4 expression. The well-orchestrated expression of the multitude of proteins involved in these adaptations is mediated by the rapid activation of PPAR gamma co-activator (PGC) 1, a protein that binds to various transcription factors to maximize transcriptional activity. Activating AMPK using 5-aminoimidizole-4-carboxamide-1-beta-D-riboside (AICAR) and increasing cytoplasmic Ca(2+) using caffeine, W7 or ionomycin in L6 myotubes increases the concentration of mitochondrial enzymes and GLUT4 and enhances the binding of NRF-1 and NRF-2 to DNA. AICAR and Ca-releasing agents also increase the levels of PGC-1, mitochondrial transcription factor A and myocyte-enhancing factors 2A and 2D. These results are similar to the responses seen in muscle during the adaptation to endurance exercise and show that L6 myotubes are a suitable model for studying the mechanisms by which exercise causes the adaptive responses in muscle mitochondria and glucose transport. AD - Department of Human Biology, University of Cape Town, Cape Town 7700, South Africa. eojuka@sports.uct.ac.za UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15294043 ID - 64 ER - TY - JOUR AU - Olkin, I. AU - Pratt, J. W. PY - 1958 TI - Unbiased estimation of certain correlation coefficients SP - 201-211 JF - Annals of Mathematical Statistics N1 - Unbiased estimation of certain correlation coefficients ID - 29 ER - TY - JOUR AU - Overend, T. J. AU - Paterson, D. H. AU - Cunningham, D. A. PY - 1992 TI - The effect of interval and continuous training on the aerobic parameters SP - 129-34 N1 - Jun JF - Can J Sport Sci VL - 17 IS - 2 N1 - The effect of interval and continuous training on the aerobic parameters N1 - 455 N1 - 1324106 Overend, T J Paterson, D H Cunningham, D A Research Support, Non-U.S. Gov't United states Canadian journal of sport sciences = Journal canadien des sciences du sport Can J Sport Sci. 1992 Jun;17(2):129-34. KW - Adult Exercise/*physiology Exercise Test Humans Male Oxygen Consumption/*physiology *Physical Education and Training Respiratory Function Tests N2 - The purpose of this study was to investigate changes in the parameters of aerobic function resulting from continuous training (CT) and interval training of both low power (LPO-IT) and high power output (HPO-IT). Untrained males (n = 17, 25.1 yrs) trained 10 weeks on cycle ergometers (four 40-min sessions a week) at 80% VO2max. Cycle ramp function tests at 0 and 10 weeks were used to determine the four aerobic parameters:VO2max, ventilation threshold (VeT), effective time constant for O2 uptake kinetics (MRT), and work efficiency (eta): VO2max increased significantly (3.30 to 3.66 l.min-1). Absolute VeT increased significantly (2.17 to 2.45 l.min-1) but there was no change in the relative threshold (VeT/VO2max). MRT decreased significantly from 38.8 to 33.1 seconds and there was no change in eta. There were no between-group differences; thus neither low power output nor high power output interval training offers an advantage over continuous training of the same average power output in altering the aerobic parameters. AD - Faculty of Kinesiology, University of Western Ontario, London. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=1324106 ID - 99 ER - TY - JOUR AU - Pelliccia, A. AU - Culasso, F. AU - Di Paolo, F. M. AU - Maron, B. J. PY - 1999 TI - Physiologic left ventricular cavity dilatation in elite athletes SP - 23-31 N1 - Jan 5 JF - Ann Intern Med VL - 130 IS - 1 N1 - Physiologic left ventricular cavity dilatation in elite athletes N1 - 1045 N1 - 9890846 Pelliccia, A Culasso, F Di Paolo, F M Maron, B J United states Annals of internal medicine Ann Intern Med. 1999 Jan 5;130(1):23-31. KW - Adolescent Adult Age Factors Cardiomyopathy, Dilated/diagnosis Diagnosis, Differential Echocardiography Electrocardiography Female Follow-Up Studies Heart Ventricles/*anatomy & histology/ultrasonography Humans Male Middle Aged Physical Education and Training Reproducibility of Results Sex Factors Sports/*physiology *Ventricular Function, Left N2 - BACKGROUND: Absolute left ventricular cavity dimension may be substantially increased in some highly trained athletes. This raises questions about the differential diagnosis between athlete's heart and dilated cardiomyopathy as well as possible disqualification from competitive sports. OBJECTIVE: To evaluate the morphologic characteristics and physiologic limits of left ventricular cavity enlargement associated with intensive, long-term athletic conditioning. DESIGN: Evaluation of left ventricular cavity dimension in a large sample of highly trained athletes. SETTING: Institute of Sports Science, Rome, Italy. PARTICIPANTS: 1309 elite Italian athletes (957 men and 352 women), 13 to 59 years of age (mean, 24 years), participating in 38 different sports. MEASUREMENTS: Echocardiographic assessment of left ventricular cavity dimension and multivariate statistical analysis of the determinants. RESULTS: Left ventricular end-diastolic cavity dimensions varied widely (38 to 66 mm [mean, 48 mm] in women and 43 to 70 mm [mean, 55 mm] in men) and was within generally accepted normal limits for most participants (< or = 54 mm in 725 athletes [55%]). According to an arbitrary clinical cut-point of 60 mm, the left ventricular cavity was substantially enlarged in 185 participants (14%). These athletes had global left ventricular systolic function within normal limits and no regional wall-motion abnormalities; participants remained free of cardiac symptoms and impaired performance over 1 to 12 years (mean, 4.7 years). The major determinants of cavity dimension were greater body surface area and participation in certain endurance sports (cycling, cross-country skiing, and canoeing). CONCLUSIONS: In a sample of highly trained athletes, left ventricular cavity dimension varied widely but was strikingly increased to a degree compatible with primary dilated cardiomyopathy in almost 15% of participants. In the absence of systolic dysfunction, this cavity dilatation is most likely an extreme physiologic adaptation to intensive athletic conditioning. The long-term consequences and significance of this marked left ventricular remodeling of the athlete's heart is not known. AD - Institute of Sports Science, Italian National Olympic Committee, and University La Sapienza, Rome. ISS-Fisiologia@coni.it UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9890846 ID - 68 ER - TY - JOUR AU - Perneger, T. V. PY - 1998 TI - What's wrong with Bonferroni adjustments SP - 1236-1238 JF - BMJ VL - 316 N1 - What's wrong with Bonferroni adjustments N1 - 26 ID - 149 ER - TY - JOUR AU - Poole, D. C. AU - Gaesser, G. A. PY - 1985 TI - Response of ventilatory and lactate thresholds to continuous and interval training SP - 1115-21 N1 - Apr JF - J Appl Physiol VL - 58 IS - 4 N1 - Response of ventilatory and lactate thresholds to continuous and interval training N1 - 85 N1 - 3988668 Poole, D C Gaesser, G A Comparative Study Research Support, Non-U.S. Gov't United states Journal of applied physiology (Bethesda, Md. : 1985) J Appl Physiol. 1985 Apr;58(4):1115-21. KW - Adaptation, Physiological Adult Differential Threshold Humans Lactates/*metabolism Male Muscles/metabolism Oxygen Consumption *Physical Education and Training Physical Endurance *Respiration N2 - The purpose of this study was to evaluate the effects of continuous and interval training on changes in lactate and ventilatory thresholds during incremental exercise. Seventeen males were assigned to one of three training groups: group 1:55 min continuous exercise at approximately 50% maximum O2 consumption (VO2max); group 2: 35 min continuous exercise at approximately 70% VO2max; and group 3: 10 X 2-min intervals at approximately 105% VO2max interspersed with rest intervals of 2 min. All of the subjects were tested and trained on a cycle ergometer 3 day/wk for 8 wk. Lactate threshold (LT) and ventilatory threshold (VT) (in addition to maximal exercise measures) were determined using a standard incremental exercise test before and after 4 and 8 wk of training. VO2max increased significantly in all groups with no statistically significant differences between the groups. Increases (+/- SE) in LT (ml O2 X min-1) for group 1 (569 +/- 158), group 2 (584 +/- 125), and group 3 (533 +/- 88) were significant (P less than 0.05) and of the same magnitude. VT also increased significantly (P less than 0.05) in each group. However, the increase in VT (ml O2 X min-1) for group 3 (699 +/- 85) was significantly greater (P less than 0.05) than the increases in VT for group 1 (224 +/- 52) and group 2 (404 +/- 85). For group 1, the posttraining increase in LT was significantly greater than the increase in VT (P less than 0.05). We conclude that both continuous and interval training were equally effective in augmenting LT, but interval training was more effective in elevating VT.(ABSTRACT TRUNCATED AT 250 WORDS) UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=3988668 ID - 104 ER - TY - JOUR AU - Reilly, T. AU - Thomas, V. PY - 1976 TI - A motion analysis of work-rate in different positional roles in professional football match-play SP - 87-97 JF - Journal of Human Movement Studies VL - 2 IS - 2 N1 - A motion analysis of work-rate in different positional roles in professional football match-play ID - 33 ER - TY - JOUR AU - Richardson, R. S. AU - Leigh, J. S. AU - Wagner, P. D. AU - Noyszewski, E. A. PY - 1999 TI - Cellular PO2 as a determinant of maximal mitochondrial O2 consumption in trained human skeletal muscle SP - 325-331 JF - Journal of Applied Physiology VL - 87 N1 - Cellular PO2 as a determinant of maximal mitochondrial O2 consumption in trained human skeletal muscle ID - 19 ER - TY - JOUR AU - Ristow, M. AU - Zarse, K. AU - Oberbach, A. AU - Kloting, N. AU - Birringer, M. AU - Kiehntopf, M. AU - Stumvoll, M. AU - Kahn, C. R. AU - Bluher, M. PY - 2009 TI - Antioxidants prevent health-promoting effects of physical exercise in humans SP - 8665-70 N1 - May 26 JF - Proc Natl Acad Sci U S A VL - 106 IS - 21 N1 - Antioxidants prevent health-promoting effects of physical exercise in humans N1 - 1120 N1 - 19433800 Ristow, Michael Zarse, Kim Oberbach, Andreas Kloting, Nora Birringer, Marc Kiehntopf, Michael Stumvoll, Michael Kahn, C Ronald Bluher, Matthias Controlled Clinical Trial Research Support, Non-U.S. Gov't United States Proceedings of the National Academy of Sciences of the United States of America Proc Natl Acad Sci U S A. 2009 May 26;106(21):8665-70. Epub 2009 May 11. KW - Adult Antioxidants/*adverse effects/*pharmacology Ascorbic Acid/adverse effects/pharmacology Biological Markers/blood Exercise/*physiology *Health Humans Insulin/blood/physiology Insulin Resistance/physiology Male Oxidative Stress/drug effects Substrate Specificity Time Factors Vitamin E/adverse effects/pharmacology N2 - Exercise promotes longevity and ameliorates type 2 diabetes mellitus and insulin resistance. However, exercise also increases mitochondrial formation of presumably harmful reactive oxygen species (ROS). Antioxidants are widely used as supplements but whether they affect the health-promoting effects of exercise is unknown. We evaluated the effects of a combination of vitamin C (1000 mg/day) and vitamin E (400 IU/day) on insulin sensitivity as measured by glucose infusion rates (GIR) during a hyperinsulinemic, euglycemic clamp in previously untrained (n = 19) and pretrained (n = 20) healthy young men. Before and after a 4 week intervention of physical exercise, GIR was determined, and muscle biopsies for gene expression analyses as well as plasma samples were obtained to compare changes over baseline and potential influences of vitamins on exercise effects. Exercise increased parameters of insulin sensitivity (GIR and plasma adiponectin) only in the absence of antioxidants in both previously untrained (P < 0.001) and pretrained (P < 0.001) individuals. This was paralleled by increased expression of ROS-sensitive transcriptional regulators of insulin sensitivity and ROS defense capacity, peroxisome-proliferator-activated receptor gamma (PPARgamma), and PPARgamma coactivators PGC1alpha and PGC1beta only in the absence of antioxidants (P < 0.001 for all). Molecular mediators of endogenous ROS defense (superoxide dismutases 1 and 2; glutathione peroxidase) were also induced by exercise, and this effect too was blocked by antioxidant supplementation. Consistent with the concept of mitohormesis, exercise-induced oxidative stress ameliorates insulin resistance and causes an adaptive response promoting endogenous antioxidant defense capacity. Supplementation with antioxidants may preclude these health-promoting effects of exercise in humans. AD - Department of Human Nutrition, Institute of Nutrition, University of Jena, Jena D-07743, Germany. mristow@mristow.org UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=19433800 ID - 72 ER - TY - BOOK AU - Robertson, D G AU - Caldwell, G AU - Hamill, J AU - Kamen, G AU - Whitlesey, S N PY - 2004 BT - Research Methods in Biomechanics CY - Champaign, IL PB - Human Kinetics N1 - Research Methods in Biomechanics ID - 23 ER - TY - JOUR AU - Robinson, D. M. AU - Robinson, S. M. AU - Hume, P. A. AU - Hopkins, W. G. PY - 1991 TI - Training intensity of elite male distance runners SP - 1078-82 N1 - Sep JF - Med Sci Sports Exerc VL - 23 IS - 9 N1 - Training intensity of elite male distance runners N1 - 832 N1 - 1943629 Robinson, D M Robinson, S M Hume, P A Hopkins, W G United states Medicine and science in sports and exercise Med Sci Sports Exerc. 1991 Sep;23(9):1078-82. KW - Adult Anaerobic Threshold Exercise Test Heart Rate/physiology Humans Lactates/blood Male Motivation Oxygen Consumption Physical Education and Training *Physical Endurance Physical Exertion/*physiology *Running United States N2 - To quantify training intensity in 13 nationally ranked male distance runners, training heart rates, environmental factors, and motivational factors were recorded throughout a 6-8 wk period of normal training. Variation in motivational and environmental factors such as intended effort, terrain, and running with companions altered training session mean heart rates by up to 4.min-1 (standard deviation). Heart rates and blood lactate concentrations, recorded in a series of steady-state treadmill runs, were used to convert training session mean heart rates to mean training speeds (TS) and to derive a measure of the anaerobic threshold (AT, the treadmill speed at a blood lactate concentration of 4 mmol.l-1). TS (15.6 +/- 1.4 km.h-1, mean +/- SD) was considerably lower than AT (20.2 +/- 1.1 km.h-1) in all subjects (P less than 0.001). Relative TS (TS expressed as a fraction of AT) differed significantly (P less than 0.001) between subjects and correlated significantly with the distance of the event for which the subject was training (r = 0.59, P less than 0.05). Relative TS may therefore be determined by the subject's or coach's perception of the appropriate intensity for the event. If the AT is the optimum training intensity, these subjects have considerable scope for improvement. AD - Department of Physiology, Univesity of Auckland, Private Bag, Auckland, New Zealand. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=1943629 ID - 55 ER - TY - JOUR AU - Saltin, B. AU - Nazar, K. AU - Costill, D. L. AU - Stein, E. AU - Jansson, E. AU - Essen, B. AU - Gollnick, D. PY - 1976 TI - The nature of the training response; peripheral and central adaptations of one-legged exercise SP - 289-305 N1 - Mar JF - Acta Physiol Scand VL - 96 IS - 3 N1 - The nature of the training response; peripheral and central adaptations of one-legged exercise N1 - 549 N1 - 132082 Saltin, B Nazar, K Costill, D L Stein, E Jansson, E Essen, B Gollnick, D Sweden Acta physiologica Scandinavica Acta Physiol Scand. 1976 Mar;96(3):289-305. KW - Adaptation, Physiological Adenosine Triphosphatases/metabolism Adult Blood Glucose/analysis Glycogen/metabolism Heart Rate Humans Lactates/blood Leg Male Muscles/enzymology/*metabolism Oxygen Consumption *Physical Exertion Succinate Dehydrogenase/metabolism Time Factors N2 - 13 male subjects were studied and placed in 3 groups. Each group exercised one leg with sprint (S), or endurance (E) training and the other leg oppositely or not at all (NT). Oxygen uptake (Vo2), heart rate and blood lactate were measured for each leg separately and for both legs together during submaximal and maximal bicycle work before and after 4 weeks of training with 4-5 sessions per week. Muscle samples were obtained from the quadriceps muscle and assayed for succinate dehydrogenase (SDH) activity, and stained for myofibrillar ATPase. In addition, eight of the subjects performed after the training two-legged exercise at 70% Vo2 max for one hour. The measurements included muscle glycogen and lactate concentrations of the two legs as well as the blood flow and the a-v difference for O2, glucose and lactate. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=132082 ID - 112 ER - TY - JOUR AU - Schumacher, Y. O. AU - Mueller, P. PY - 2002 TI - The 4000-m team pursuit cycling world record: theoretical and practical aspects SP - 1029-36 N1 - Jun JF - Med Sci Sports Exerc VL - 34 IS - 6 N1 - The 4000-m team pursuit cycling world record: theoretical and practical aspects N1 - 202 N1 - 12048333 Schumacher, Yorck Olaf Mueller, Peter Review United States Medicine and science in sports and exercise Med Sci Sports Exerc. 2002 Jun;34(6):1029-36. KW - Anthropometry Bicycling/*physiology Competitive Behavior/*physiology Humans Models, Biological Physical Education and Training/*methods Predictive Value of Tests Sports Medicine/methods Task Performance and Analysis N2 - Due to constant competition conditions, track cycling can be accurately modeled through physiological and biomechanical means. Mathematical modeling predicts an average workload of 520 W for every team member for a new team pursuit world record. Performance in team pursuit racing is highly dependent on aerobic capacity, anaerobic skills, and aerodynamic factors. The training concept of the 2000 record-breaking team pursuit team was based on unspecific training of these qualities and periodical, short-term recall of previously acquired track specific skills. Aerobic performance was trained through high overall training mileage (29,000-35,000 km.yr-1) with workload peaks during road stage races. Before major track events, anaerobic performance, and track-specific technical and motor skills were improved through discipline-specific track training. Training intensities were monitored through heart rate and lactate field tests during defined track-training bouts, based on previously performed laboratory exercise tests. During pursuit competition, analysis of half-lap split times allowed an estimation of the individual contribution of each rider to the team's performance and thereby facilitated modifications in team composition to optimize race speed. The theoretically predicted performance necessary for a new world record was achieved through careful planning of training and competition schedules based on a concise theoretical concept and the high physiological capacities of the participating athletes. AD - Medizinische Universitatsklinik, Abteilung Rehabilitative und Praventive Sportmedizin, Freiburg, Germany. olaf@msm1.ukl.uni-freiburg.de UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12048333 ID - 48 ER - TY - JOUR AU - Seiler, K. S. AU - Kjerland, G. O. PY - 2006 TI - Quantifying training intensity distribution in elite endurance athletes: is there evidence for an "optimal" distribution? SP - 49-56 N1 - Feb JF - Scand J Med Sci Sports VL - 16 IS - 1 N1 - Quantifying training intensity distribution in elite endurance athletes: is there evidence for an "optimal" distribution? N1 - 122 N1 - 16430681 Seiler, K Stephen Kjerland, Glenn Ovrevik Denmark Scandinavian journal of medicine & science in sports Scand J Med Sci Sports. 2006 Feb;16(1):49-56. KW - Adolescent Exercise/*physiology Exercise Test Heart Rate Humans Lactates Lactic Acid/blood Male Oxygen Consumption Physical Education and Training Physical Endurance/*physiology Physical Exertion Prospective Studies Skiing/*physiology N2 - This study was designed to quantify the daily distribution of training intensity in a group of well-trained junior cross-country skiers and compare the results of three different methods of training intensity quantification. Eleven male athletes performed treadmill tests to exhaustion to determine heart rate and VO2 corresponding to ventilatory thresholds (VT1, VT2), maximal oxygen consumption (VO2max), and maximal heart rate. VT1 and VT2 were used to delineate three intensity zones. During the same time period, all training sessions (N=384, 37 strength training, 347 endurance) performed over 32 consecutive days were quantified using continuous heart rate registration and session Rating of Perceived Exertion (RPE). In addition, a subset of 60 consecutive training sessions was quantified using blood lactate measurements. Intensity distribution across endurance training sessions (n=318) was similar when based on heart rate analysis (75+/-3%, zone 1; 8+/-3%, zone 2; 17+/-4%, zone 3) or session RPE (76+/-4%, zone 1; 6+/-5%, zone 2; 18+/-7%, zone 3). Similarly, from measurements of 60 consecutive sessions, 71% were performed with or=90 min after the same interval session. CONCLUSIONS: In the highly trained endurance athlete, exercise for 65 and >80 years old, respectively. Despite this, most previous studies have excluded patients with an age >70 years. Our objective was to compare training programs with moderate versus high exercise intensity with regard to variables associated with cardiovascular function and prognosis in patients with postinfarction heart failure. METHODS AND RESULTS: Twenty-seven patients with stable postinfarction heart failure who were undergoing optimal medical treatment, including beta-blockers and angiotensin-converting enzyme inhibitors (aged 75.5+/-11.1 years; left ventricular [LV] ejection fraction 29%; VO2peak 13 mL x kg(-1) x min(-1)) were randomized to either moderate continuous training (70% of highest measured heart rate, ie, peak heart rate) or aerobic interval training (95% of peak heart rate) 3 times per week for 12 weeks or to a control group that received standard advice regarding physical activity. VO2peak increased more with aerobic interval training than moderate continuous training (46% versus 14%, P<0.001) and was associated with reverse LV remodeling. LV end-diastolic and end-systolic volumes declined with aerobic interval training only, by 18% and 25%, respectively; LV ejection fraction increased 35%, and pro-brain natriuretic peptide decreased 40%. Improvement in brachial artery flow-mediated dilation (endothelial function) was greater with aerobic interval training, and mitochondrial function in lateral vastus muscle increased with aerobic interval training only. The MacNew global score for quality of life in cardiovascular disease increased in both exercise groups. No changes occurred in the control group. CONCLUSIONS: Exercise intensity was an important factor for reversing LV remodeling and improving aerobic capacity, endothelial function, and quality of life in patients with postinfarction heart failure. These findings may have important implications for exercise training in rehabilitation programs and future studies. AD - Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Olav Kyrres gt. 9, 7489 Trondheim, Norway. ulrik.wisloff@ntnu.no UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=17548726 ID - 34 ER - TY - JOUR AU - Yan, Z. PY - 2009 TI - Exercise, PGC-1alpha, and metabolic adaptation in skeletal muscle SP - 424-7 N1 - Jun JF - Appl Physiol Nutr Metab VL - 34 IS - 3 N1 - Exercise, PGC-1alpha, and metabolic adaptation in skeletal muscle N1 - 929 N1 - 19448709 Yan, Zhen AR050429/AR/NIAMS NIH HHS/United States Research Support, N.I.H., Extramural Review Canada Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme Appl Physiol Nutr Metab. 2009 Jun;34(3):424-7. KW - Adaptation, Physiological/*physiology Animals Gene Expression Regulation Mice Muscle, Skeletal/*metabolism Physical Conditioning, Animal/*physiology Signal Transduction/physiology Trans-Activators/*metabolism N2 - Endurance exercise promotes skeletal muscle adaptation, and exercise-induced peroxisome proliferator-activated receptor gamma coactivator-1alpha (Pgc-1alpha) gene expression may play a pivotal role in the adaptive processes. Recent applications of mouse genetic models and in vivo imaging in exercise studies have started to delineate the signaling-transcription pathways that are involved in the regulation of the Pgc-1alpha gene. These studies revealed the importance of p38 mitogen-activated protein kinase/activating transcription factor 2 and protein kinase D/histone deacetylase 5 signaling transcription axes in exercise-induced Pgc-1alpha transcription and metabolic adaptation in skeletal muscle. The signaling-transcription network that is responsible for exercise-induced skeletal muscle adaption remains to be fully elucidated. AD - Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA. zhen.yan@virginia.edu UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=19448709 ID - 78 ER - TY - JOUR AU - Yeo, W. K. AU - Paton, C. D. AU - Garnham, A. P. AU - Burke, L. M. AU - Carey, A. L. AU - Hawley, J. A. PY - 2008 TI - Skeletal muscle adaptation and performance responses to once a day versus twice every second day endurance training regimens SP - 1462-70 N1 - Nov JF - J Appl Physiol VL - 105 IS - 5 N1 - Skeletal muscle adaptation and performance responses to once a day versus twice every second day endurance training regimens N1 - 1395 N1 - 18772325 Yeo, Wee Kian Paton, Carl D Garnham, Andrew P Burke, Louise M Carey, Andrew L Hawley, John A Comparative Study Research Support, Non-U.S. Gov't United States Journal of applied physiology (Bethesda, Md. : 1985) J Appl Physiol. 2008 Nov;105(5):1462-70. Epub 2008 Sep 4. KW - 3-Hydroxyacyl CoA Dehydrogenases/metabolism AMP-Activated Protein Kinases/metabolism Adaptation, Physiological Adult *Bicycling Citrate (si)-Synthase/metabolism DNA, Mitochondrial/metabolism Electron Transport Complex IV/metabolism *Energy Metabolism Glycogen/metabolism Heat-Shock Proteins/metabolism Humans Lipid Metabolism Male Mitochondria, Muscle/enzymology/*metabolism Muscle, Skeletal/enzymology/*metabolism Oxidation-Reduction Phosphorylation *Physical Endurance Time Factors Transcription Factors/metabolism N2 - We determined the effects of a cycle training program in which selected sessions were performed with low muscle glycogen content on training capacity and subsequent endurance performance, whole body substrate oxidation during submaximal exercise, and several mitochondrial enzymes and signaling proteins with putative roles in promoting training adaptation. Seven endurance-trained cyclists/triathletes trained daily (High) alternating between 100-min steady-state aerobic rides (AT) one day, followed by a high-intensity interval training session (HIT; 8 x 5 min at maximum self-selected effort) the next day. Another seven subjects trained twice every second day (Low), first undertaking AT, then 1-2 h later, the HIT. These training schedules were maintained for 3 wk. Forty-eight hours before and after the first and last training sessions, all subjects completed a 60-min steady-state ride (60SS) followed by a 60-min performance trial. Muscle biopsies were taken before and after 60SS, and rates of substrate oxidation were determined throughout this ride. Resting muscle glycogen concentration (412 +/- 51 vs. 577 +/- 34 micromol/g dry wt), rates of whole body fat oxidation during 60SS (1,261 +/- 247 vs. 1,698 +/- 174 micromol.kg(-1).60 min(-1)), the maximal activities of citrate synthase (45 +/- 2 vs. 54 +/- 1 mmol.kg dry wt(-1).min(-1)), and beta-hydroxyacyl-CoA-dehydrogenase (18 +/- 2 vs. 23 +/- 2 mmol.kg dry wt(-1).min(-1)) along with the total protein content of cytochrome c oxidase subunit IV were increased only in Low (all P < 0.05). Mitochondrial DNA content and peroxisome proliferator-activated receptor-gamma coactivator-1alpha protein levels were unchanged in both groups after training. Cycling performance improved by approximately 10% in both Low and High. We conclude that compared with training daily, training twice every second day compromised high-intensity training capacity. While selected markers of training adaptation were enhanced with twice a day training, the performance of a 1-h time trial undertaken after a 60-min steady-state ride was similar after once daily or twice every second day training programs. AD - Exercise Metabolism Group, School of Medical Sciences, Bldg. 223.2.52, RMIT University, PO Box 71, Bundoora, Victoria 3083, Australia. UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=18772325 ID - 71 ER - TY - JOUR AU - Zapico, A. G. AU - Calderon, F. J. AU - Benito, P. J. AU - Gonzalez, C. B. AU - Parisi, A. AU - Pigozzi, F. AU - Di Salvo, V. PY - 2007 TI - Evolution of physiological and haematological parameters with training load in elite male road cyclists: a longitudinal study SP - 191-6 N1 - Jun JF - J Sports Med Phys Fitness VL - 47 IS - 2 N1 - Evolution of physiological and haematological parameters with training load in elite male road cyclists: a longitudinal study N1 - 845 N1 - 17557057 Zapico, A G Calderon, F J Benito, P J Gonzalez, C B Parisi, A Pigozzi, F Di Salvo, V Italy The Journal of sports medicine and physical fitness J Sports Med Phys Fitness. 2007 Jun;47(2):191-6. KW - Adult Analysis of Variance Bicycling/*physiology Exercise Test Hemoglobins/analysis Humans Lactates/blood Longitudinal Studies Male Nutritional Status Oxygen Consumption/physiology Physical Education and Training/*methods Urea/blood N2 - AIM: The aim of this study was to describe and evaluate physiological parameters as a control tool for the monitoring of training in a group of elite cyclists during one season of training. METHODS: The study is divided into two periods (winter or ''volume'' mesocycle and spring or ''intensity'' mesocycle) between the tests that they carried out in the laboratory, consisting of a ramp test to exhaustion (work load increases 25 W X min(-1)) and a maximal lactate steady state (MLSS) test on a cycle ergometer. Macronutrients and hematological variables were recorded during the test periods as were the volume and the intensity of training sessions during the whole period of the study. RESULTS: The physiological data were similar to those previously reported for professional cyclists (approximately 450 Watts, approximately 78 mL x kg(-1) x min(-1)) and the values for the MLSS also agree with previous studies (approximately 250 Watts). Subjects improved the first ventilatory threshold (VT(1)) (approximately 52% to approximately 60% VO(2max)) and the second ventilatory threshold (VT(2)) (approximately 82% to approximately 87% VO(2max)) after the first period of training even though its low intensity focused on the performance of VT(1) (77% training in ''zone 1'', under VT(1)). The MLSS improved after the first period (approximately 225 to approximately 250 Watts) and remained high in the second (approximately 255 Watts). High levels of creatine kinase (approximately 230 U x L(-1)) and urea (37 mg x L(-1)) were found, also a decrease in hemoglobin values (approximately 15.4 to approximately 14.7g x dL(-1)). CONCLUSION: The high level reached by the subjects after the first period of training suggests that two effort tests could be enough to plan training. On the other hand, the decrease in some red blood cell and nutrition parameters suggests that there should be greater control over them during the season. AD - Education Faculty, Complutense University of Madrid, Madrid, Spain. azapico@edu.ucm.es UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=17557057 ID - 86 ER - TY - JOUR AU - Zhou, B. AU - Conlee, R. K. AU - Jensen, R. AU - Fellingham, G. W. AU - George, J. D. AU - Fisher, A. G. PY - 2001 TI - Stroke volume does not plateau during graded exercise in elite male distance runners SP - 1849-54 N1 - Nov JF - Med Sci Sports Exerc VL - 33 IS - 11 N1 - Stroke volume does not plateau during graded exercise in elite male distance runners N1 - 554 N1 - 11689734 Zhou, B Conlee, R K Jensen, R Fellingham, G W George, J D Fisher, A G Clinical Trial Comparative Study Controlled Clinical Trial Research Support, Non-U.S. Gov't United States Medicine and science in sports and exercise Med Sci Sports Exerc. 2001 Nov;33(11):1849-54. KW - Adult Cardiac Output Exercise/*physiology Exercise Test Heart Rate Humans Male Oxygen Consumption Physical Education and Training/*methods Physical Fitness/*physiology Reference Values Rest/physiology Running/*physiology Stroke Volume/*physiology N2 - Stroke volume (SV) responses during graded treadmill exercise were studied in 1) elite male distance runners (N = 5), 2) male university distance runners (N = 10), and 3) male untrained university students (N = 10). METHODS: Cardiac output (Q) and SV were determined by a modified acetylene rebreathing procedure. RESULTS: There were no differences in SV responses among the three groups during the transition from rest to light exercise (P > 0.05). However, the rates of change of SV during light to maximal exercise in untrained subjects (slope = -0.1544 mL x beat(-1)) and university distance runners (slope = 0.1041) did not change, whereas it dramatically increased (P < 0.001) in elite distant runners (slope = 0.6734). Moreover, the elite distance runners showed a further slope increase in SV when heart rate was above 160 bpm, which resulted in an average maximal SV of 187 +/- 14 mL x beat(-1) compared with 145 +/- 8 and 128 +/- 14 mL x beat(-1) in the university runners and untrained students, respectively (P < 0.001). Similarly, max Q reached 33.8 +/- 2.3, 26.3 +/- 1.7, and 21.3 +/- 1.5 L x min(-1) in the three groups, respectively (P < 0.001). On the other hand, there was a nonsignificant tendency for maximal arteriovenous oxygen content difference to be lower in the elite athletes compared with the other groups. CONCLUSION: Results from university distance runners and untrained university students support the classic observation that SV plateaus at about 40% of maximal oxygen consumption despite increasing intensity of exercise. In contrast, stroke volume in the elite athletes does not plateau but increases continuously with increasing intensity of exercise over the full range of the incremental exercise test. AD - Human Performance Research Center and Department of Statistics, Brigham Young University, Provo, UT 84602, USA. bzhou@research.csudh.edu UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11689734 ID - 105 ER -