SPORTSCIENCE |
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Original Research / Training |
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High-Resistance
Interval Training Improves 40-km Time-Trial
Performance in Competitive Cyclists
Amy M
Taylor-Mason
Sportscience 9, 27-31, 2005
(sportsci.org/jour/05/amt-m.htm)
Kinetic Edge Cycling, Box 25941, Auckland, New Zealand. Email.
Reviewer: Carl D Paton, Centre for Sport and Exercise Science, Waikato Institute
of Technology, Hamilton, NZ.
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Interval training at race-specific high cadences
improves endurance cycling performance, but there is evidence that adding
resistance to reduce the cadence might be more effective. AIM. To determine the effect of high-resistance
interval training on endurance performance of male cyclists during the
competition phase of a season.
METHODS. In a randomized controlled trial, 10 cyclists in a control
group maintained usual training and competing while 12 cyclists in an experimental
group replaced part of their usual training with high resistance interval
training twice weekly for 8 wk. Mean power in a 40-km simulated time trial,
maximal oxygen consumption (VO2max),
incremental peak power, body composition, and leg strength were measured
before and after training. RESULTS.
Relative to control training, there were clear beneficial effects of
resistance training on 40-km mean power (7.6%, 90% confidence limits
±5.0%). There were also clear
beneficial effects on incremental peak power (3.5%, ±4.2%), VO2max in ml.min‑1.kg‑1 (6.6%, ±7.0%), and
sum of 8 skinfolds (‑12%, ±11%).
Effects on body mass (‑1.6%, ±1.9%) and thigh muscle area (0.6%,
±2.7%) were possibly trivial. Effects
on VO2max in L.min‑1 and three measures of isokinetic leg strength
were unclear, owing to large errors of measurement. CONCLUSIONS.
High-resistance interval training produces a major enhancement in endurance
power of athletes in the competitive season.
The benefits of this form of training should transfer to competitive
performance. KEYWORDS: endurance,
strength, VO2max. Reprint pdf · Reprint doc · Commentary by Carl Paton Update 6Feb06: Correction to peak power in Table 2. |
In a review published at this site last year,
Paton and Hopkins (2004) summarized the evidence for beneficial effects of
various kinds of high-intensity resistance and interval training on the
endurance performance of competitive athletes.
Although the gains in endurance power output on average were up to 8%,
"all but one study was performed in non-competitive phases of the
athletes’ programs, when there was otherwise little or no high-intensity
training". They suggested that the
gains would probably be less if the high-intensity training were performed in
the competitive phase, when athletes normally include higher intensity training
in their programs. Indeed, in the only pervious training study performed during
the competitive phase of a season (Toussaint and Vervoorn, 1990),
sport-specific resistance training enhanced competitive time-trial performance
of swimmers by an amount equivalent to a useful but smaller ~2% in power
output. In a follow-up study, Paton and Hopkins
(2005) observed improvements of 6-9% in various measures of endurance
power. Evidently, some forms of
resistance training can be very effective, even during a competitive
phase.
I was also
interested in the benefits of resistance training for endurance performance,
and coincidentally performed a study on cyclists during the same competitive
season that Paton and Hopkins performed their training study. The outcome is the basis of this paper.
Twenty-four well-trained male cyclists were
recruited through Auckland cycling clubs.
All subjects provided informed written consent in accordance with the University
of Auckland human subjects ethics committee.
All subjects in the study were in the competition phase of their
training and were free of injury and illness.
A description of the subject groups is shown in Table 1.
Subjects were randomly assigned in to either
an experimental high-resistance interval-training or a control normal-training
group. Two subjects in the control group
withdrew before the completion of the study.
Subjects in the experimental group performed eight weeks of supervised
high resistance interval training twice per week, in addition to their normal
low intensity endurance training. The
control group continued with their normal training programs which was a
combination of high intensity racing, and low intensity endurance training. All subjects were given detailed training
logs to complete four weeks prior to, and during the eight week intervention
period. All subjects repeated the
testing procedures 4-10 d following the completion of the intervention.
Prior to testing, subjects were instructed
to refrain from intensive training, caffeine, and alcohol for 24 hours, and to
remain on their normal diet. This
investigation was a pre-post design, thus the following procedures were
conducted within one week pre- and one week post-intervention. All testing procedures allowed a minimum of
48 h recovery between tests. On the
first visit to the laboratory, subjects were weighed and sum of eight skinfolds
were measured using skinfold calipers (Holtain, UK). Maximal aerobic capacity (VO2max) was then measured using an incremental
(ramp) protocol with the subject's own racing bicycles mounted on the Kingcycle
ergometer (KingCycle, High Wycombe, UK), which was calibrated prior to each
test. An initial workload of 100 W was
increased 33 W each minute until volitional fatigue. VO2 was measured from analysis of expired gases
(AMETEK OCM-2, Thermox Instruments, Pittsburgh Pa). VO2 was averaged over 20-s intervals. A computer interfaced with the
Kingcycle ergometer measured power throughout the test and peak power was
defined as the highest mean power recorded over any 60-second period of the
incremental test.
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Table 1. Subject characteristics, including baseline performance and anthropometric measures for the control and experimental groups. |
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Experimental |
Control |
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Age (y) |
30 ± 8 |
32 ± 3 |
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Height (m) |
1.8 ± 0.0 |
1.8 ± 0.1 |
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Body mass (kg) |
78 ± 4 |
79 ± 14 |
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Cycling experience (y) |
10.6 ± 6.3 |
11.2 ± 5.4 |
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Training per week (h) |
11.8 ± 4.3 |
11.0 ± 4.7 |
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Sum of 8 skinfolds (mm) |
87 ± 36 |
87 ± 36 |
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Mid-thigh muscle area (cm2) |
213 ± 19 |
209 ± 37 |
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VO2max (L.min‑1) |
4.8 ± 0.4 |
4.8 ± 0.5 |
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VO2max (ml.min‑1.kg‑1) |
61.4 ± 6.0 |
62.2 ± 8.5 |
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Incremental peak power (W) |
469 ± 33 |
472 ± 72 |
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40-km time (min) |
54.0 ± 2.2 |
54.1 ± 3.2 |
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40-km mean power (W) |
317 ± 32 |
317 ± 52 |
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Peak torque at 180°.s‑1 |
266 ± 25 |
239± 49 |
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Peak torque at 270°.s‑1 |
233 ± 26 |
213 ± 44 |
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Peak torque at 360°.s‑1 |
205 ± 26 |
185 ± 32 |
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Data are mean ± standard deviation. VO2max: maximum oxygen consumption. |
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Gluteal and quadricep concentric muscle
strength was measured 30 min after the VO2max test using a Biodex
isokinetic dynamometer. The subject’s
hip and knee angles were positioned to simulate top dead centre or the start of
the power phase of the pedaling cycle as described by Faria and Cavanaugh
(1978). The movement involved hip and
knee extension to bottom dead centre or just prior to full knee extension. Maximal repetitions at isokinetic leg speeds
of 180, 270 and 360°.s‑1 (3.1, 4.7 and 6.3 radians.s‑1)
were performed five times and peak torque was recorded as the highest of the
five values. These speeds equate to 30,
45, 60 revs.min‑1 on the bicycle, which represent the range
of cadences used in the high-resistance interval-training program.
On a second visit to the laboratory,
subjects performed a 40-km cycling time trial on the Kingcycle ergometer. To ensure that subjects gave their maximum
effort they were informed that they would receive incremental financial rewards
if they completed the time trial at or above 70% of their individual peak power
measured on the first visit and post intervention incentives based on
improvement. Subjects were permitted to
consume fluids ad libitum during the time trial.
Cyclists in the high resistance interval training
group performed prolonged rides in the laboratory twice per week, during which
low cadence (40–80 revs.min‑1)
intervals were performed as suggested by Polishuk (1994). All interval training sessions were
supervised by the primary investigator.
Sessions consisted of 5-6 intervals of 3 to 22 minutes, and the total
interval duration per session increased steadily from 25 min in Week 1 through
55 min in Week 8. Rest periods in between work intervals ranged from
Each dependent variable was analyzed with a
published spreadsheet that used log transformation to estimate the effect of
training as the difference in the mean percent change between the experimental
and control groups (Hopkins, 2003). Each
spreadsheet provided precision of the estimate as 90% confidence limits and as
chances the true effect was practically beneficial and harmful. For calculation
of the chances of benefit and harm, the following values of smallest worthwhile
effects were entered into the spreadsheet for each variable: 1.5% and 0.65% for 40-km mean power and time respectively (Paton and
Hopkins, 2006); 1.5% for peak power, VO2max, and power-to-weight ratio (on the assumption that changes in
these variables translate directly into changes in mean power in a time trial);
and a standardized mean difference of 0.20 for all other measures (Hopkins,
2003). Practical inferences were drawn
using the approach described elsewhere in this journal (Batterham and Hopkins,
2005). Briefly, if chance of
benefit and harm were both >5%, the true effect was assessed as unclear
(could be beneficial or harmful).
Otherwise, quantitative chances of benefit or harm were assessed
qualitatively as follows: <1%, almost certainly not; 1-5%, very unlikely;
5-25%, unlikely; 25-75%, possible; 75-95%, likely; 95-99, very likely; >99%,
almost certain. Each spreadsheet also calculated a standard
deviation representing individual responses to the treatment (typical variation
about the mean effect from subject to subject) and another standard deviation
representing the typical error of measurement in the control group between pre
and post tests.
There was little difference in mean characteristics and baseline performance in the two groups (Table 1). The main effect of the intervention period was a substantial enhancement of performance in the 40-km time trial, due mainly to an enhancement in the experimental group and a relatively small impairment in the control group (Table 2). The nett effect on VO2max was similar in magnitude when expressed relative to body mass but a little smaller and unclear when expressed in absolute units. The experimental group also experienced a substantial reduction in skinfold thickness relative to the control group, but changes in body mass and mid-thigh muscle area were more likely to be trivial. The isokinetic testing produced unclear outcomes.
Standard errors of measurement for the control group between pre and post tests were: 40-km time-trial time, 1.7%; 40-km time-trial mean power, 4.3%; incremental peak power, 4.8%; VO2max (ml.min‑1.kg‑1), 7.7%; VO2max (L.min‑1), 7.5%; body mass, 1.8%; sum of 8 skinfolds, 11%; mid-thigh muscle area, 2.3%; and peak torques, 8-11%. The 90% confidence limits for the true values of the error of measurement were ´/¸1.5 for all measures.
Standard deviations representing individual responses had too much uncertainty for any firm conclusions; for example, the value for 40-km time-trial mean power was 4.4%, but the 90% confidence limits were -5.2% to 8.4%. About half the measures had negative standard deviations for individual responses (owing to greater variation in the change scores in the control group), but the confidence limits all allowed for the possibility of substantial real individual responses.
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Table 2. Effect of 8 weeks of high resistance interval training on cycling performance, physiological and anthropometric parameters. |
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Change in measure (%) |
Practical inferencea |
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Experimental |
Control |
Difference; |
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Performance measures |
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40-km time-trial mean power |
6.4 ± 7.7 |
-1.1 ± 6.2 |
7.6; ±5.0 |
Very likely beneficial |
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40-km time-trial time |
-2.3 ± 2.9 |
0.6 ± 2.5 |
-2.9; ±2.0 |
Very likely beneficial |
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Incremental peak powerb |
6.1 ± 3.3 |
4.1
± 5.1 |
2.0;
±3.5 |
Possibly beneficial |
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Physiological and anthropometric measures |
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VO2max (L.min‑1) |
3.8 ± 6.1 |
-0.6 ± 10.8 |
4.4; ±6.7 |
Unclear |
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VO2max (ml.min‑1.kg‑1) |
4.6 ± 6.8 |
-1.9 ± 11.1 |
6.6; ±7.0 |
Probably beneficial |
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Body mass |
-0.8 ± 2.6 |
0.8 ± 2.5 |
-1.6; ±1.9 |
Possibly trivial |
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Sum of 8 skinfolds |
-8 ± 14 |
5 ± 16 |
-12; ±11 |
Probably beneficial |
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Mid-thigh muscle area |
2.4 ± 4.2 |
1.8 ± 3.3 |
0.6; ±2.7 |
Probably trivial |
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Peak torque at 180°.s‑1 |
-2 ± 15 |
2 ± 13 |
-4; ±10 |
Unclear |
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Peak torque at 270°.s‑1 |
1 ± 12 |
-1 ± 16 |
1 ±11 |
Unclear |
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Peak torque at 360°.s‑1 |
1 ± 15 |
1 ± 13 |
0; ±10 |
Unclear |
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±90%CL: add and subtract this number to the mean effect to obtain the 90% confidence limits for the true difference. aBased on the following smallest worthwhile changes in performance: 1.5% for 40-km mean power, peak power at VO2max, VO2max, and power-to-weight ratio; 0.65% for 40-km time; standardized mean difference of 0.20 for all other measures. bData shown after deletion of one control subject who showed a decline in performance of 10% in the post test. |
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The main finding of this investigation was that eight weeks of low-cadence high-resistance interval training improved mean power by ~8% in a 40-km time trial in well-trained male cyclists. Furthermore, these improvements occurred during the competition phase of the racing season, when the cyclists were already training and competing at high intensity. The improvements, and those in incremental peak power and VO2max, are similar to those in most previous studies of high-intensity interval and resistance training, when the uncertainty in all the estimates is taken into account.
The main difference between the present study and most other previous studies is that the improvements occurred during the competition phase of a racing season, when the athletes were already training and competing at high intensity. Inasmuch as the smallest worthwhile increase in performance for an elite cycling time-trialist is ~1.5% (Paton and Hopkins, 2006), the gains I have observed represent major enhancements. Only two other published studies of effects of high-intensity training on endurance athletes have been performed during a competition phase. The enhancements in my study were greater than the ~2% observed in a study of swimmers (Toussaint and Vervoorn, 1990), possibly because the low-cadence training I achiev