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PERFORMANCE
GENE DISCOVERED
Will
G Hopkins PhD, Physiology and Physical Education, University of Otago,
Dunedin 9001, New Zealand. Sportscience 2(4), sportsci.org/jour/9804/brief.html#gene,
1998 (475 words)
To be a top athlete you need the right genes.
Sure, but until this year, no-one knew what those genes were. Now one has
been discovered. It's called the ACE gene, because it codes for the enzyme
that activates the hormone angiotensin--ACE is short for angiotensin
converting enzyme.
A group working in London knew that ACE is active in
muscle tissue, where it regulates blood flow, so they figured it might have a
role in endurance performance. They knew that the gene comes in two forms--I
(for insertion) and D (for deletion)--so they did a study to find out if
endurance athletes are more likely to have one or other form. The athletes
they chose were elite mountaineers who could ascend above 7000 m without
oxygen. Bingo! The I form was much more prevalent amongst the mountaineers
than in the general population. What's more, the mountaineers who could go to
the highest altitudes without oxygen had two copies of the I form (one from
mom and one from dad). The researchers then showed that the I form of the
gene produced a greater response to strength-endurance training in army
recruits: after a 10-week training program, time to exhaustion in a weighted
elbow-flexion exercise lasting 2 min increased by only 6% in the recruits
with two copies of the D form, by 21% in those with an I and a D, and by 66%
in those with two Is. The findings were published in the May 21 issue of
Nature (Montgomery et al., 1998). Two months later an Australian group
reported that the I form of the ACE gene was much more frequent amongst elite
rowers than in the general population (Gayagay et al., 1998).
There are several important implications. First,
athletes in endurance sports will show a better response to training if they
have two copies of the I form of the ACE gene, so it won't be long before
talent identification includes DNA testing. Will that be any different from
selecting on the basis of maximum oxygen uptake? Secondly, other genes
predictive of athletic potential will soon be discovered, but no gene will
ever substitute for hard training, good coaching, and good sport-science
support. Finally, sport scientists doing training studies with endurance
athletes should think seriously about getting their subjects DNA tested,
because the presence of the I form will help explain individual differences
in the response to training.
Gayagay G, Yu B, Hambly B, et al. (1998).
Elite endurance athletes and the ACE I allele - the role of genes in athletic
performance. Human Genetics 103, 48-50
Montgomery HE, Marshall R, Hemingway H, et
al. (1998). Human gene for physical performance. Nature 393, 221-222
For another aspect of the impact of genes
on sport performance, see the item on African
genes in the July-August issue of
Ferret.
SKELETON IN THE FREEZER
Stephen
Seiler PhD, Institute for Sport, Agder College, 4604 Kristiansand,
Norway. Email: stephen.seiler=AT=hia.no. Sportscience 2(4),
sportsci.org/jour/9804/brief.html#freeze, 1998 (338 words)
If Professor Roald Bahr of the Norwegian
University of Sport has his way, that skeleton would take the form of an
extra blood sample drawn from athletes during testing for illegal but currently
undetectable substances such as injected erythropoietin (EPO). The idea is to
create a so-called C sample.
Currently, cross-country skiers and professional
cyclists in theory give two blood samples: the A sample, which is analyzed
immediately, and the B sample, which serves as a verification sample in the
event of an initial positive. Bahr suggests that a third sample should be
drawn and deep frozen immediately for later analysis when new, more advanced
detection techniques are developed. He argues that the increased threat of
being retroactively caught for doping months or even years later would serve
as an added deterrent against the use of EPO and other substances that
currently cannot be detected in a judicially air-tight manner. Today, a "positive"
EPO test is based on hemoglobin concentration or hematocrit being over a
pre-defined limit. Because of the uncertainty of this indirect method,
athletes testing positive are merely denied participation until they are back
to a legal level.
Olympic gold medalist cross-country skiers Thomas
Alsgaard and Vegard Ulvang (retired) approve of the idea of a C sample.
According to Alsgaard, "All methods that scare are positive. A lot of
substances are currently used that the doping-hunters don't even know
about." Ulvang is now engaged at the international administrative level
by FIS, the International Ski Federation. He adds, "A very clever
suggestion. This can scare someone from doing something illegal." The
suggestion has also drawn support from the Norwegian cycling community,
including newly-crowned U-23 world time trial champion Thor Hushovd. The
suggestion is currently under political and judicial evaluation by the
Norwegian Sports Federation.
Meanwhile, international steeplechaser Jim Svenøy
also welcomes a C sample, but points out the question is moot within track
and field. The International Amateur Athletic Federation does not employ
blood testing at all, despite suspicions that EPO is widely used among
distance runners.
ONE SET OR MORE?
Frederick
C Hatfield PhD, International Sports Sciences Association, Santa Barbara,
California 93101. Email: drsquat=AT=issaonline.com.
Sportscience 2(4), sportsci.org/jour/9804/brief.html#sets, 1998 (734
words)
For most folks a session of strength training
at the gym means a circuit of exercises repeated for three or more sets.
According to all the text books, performing multiple sets of an exercise
gives you greater gains in strength than performing a single set of the
exercise. But in a recent review Carpinelli and Otto conclude that several
sets of a strength-training exercise are no more effective than a single set.
Their method requires you to choose a weight which you literally fail to lift
somewhere around the tenth repetition. All you do in your workout for each
exercise is one such set. It's a style known as high-intensity training,
or HIT.
Subscribers to the Sportscience mailing list will
recall a vigorous debate about this style of training in July last year. It
transpired that the devotees of HIT are widely regarded as a commercially
motivated fringe group whose ideas fly in the face of experience and
objective evidence. I am now concerned that some of their ideas will gain
legitimacy from this review, which is deeply flawed. In particular...
- The gains in
strength in almost all of the studies reviewed by C&O are too
small. For example, they cited a study by Stowers et al. (1983)
showing gains of 15%, 20% and 27% for 1 set, 3 sets, and a periodized
training protocol respectively. Stowers et al. suggested that
significant differences are more difficult to produce when using small
muscle mass exercises. More recent evidence also supports this view
(Stone et al., 1991,1998). Multiple sets employing exercises that
involve greater muscle mass produce gains equaling 100-170% or more in
previously untrained subjects (e.g., Fiaterone et al., 1990; Morgan et
al., 1995; Nau et al., 1998). Somehow the comparison studies in the
C&O review have been loaded against multiple sets, possibly by
restricting the review to studies of smaller muscle mass.
(Incidentally, C&O commented that there were no differences
between the groups in the Stowers et al. study, but that is clearly
not so.)
- Most of the
studies in the review are of untrained subjects, who gain strength
with any form of training in programs of 12 weeks or less. Most of the
gains stem from neural factors rather than muscle hypertrophy
(Abernathy et al., 1996; Hakkinen, 1985, 1994; Stone, 1993). But when
it comes to prolonged training programs--well beyond the 12-week
protocol typical of the studies reviewed by C&O--recent and other
studies not included in the review favor multiple sets for both well
trained and sedentary subjects (e.g., Marx et al., 1998).
- In any case, gains
in strength are only one aspect of strength training. The majority of
gym-going customers want to LOOK strong. There is little doubt that
multiple sets produce bigger gains in muscle hypertrophy than single
sets, despite C&O's claim to the contrary.
- Injury and
overtraining are known hazards of weight training, especially if it
does not employ periodization. Both appear more likely when training
to failure, whether using one set or multiple sets. In a recent review
Stone et al. (1998) noted that training to failure produces
considerable fatigue. Fatigue increases the risk of injury, probably
through changes in movement patterns. Additionally, the work of
Nimmons et al. (1995) suggests that training to failure and beyond
(e.g., forced reps) on a consistent basis can lead to overtraining.
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My advice: keep doing multiple
sets, periodize your training intensity, and watch for a thorough objective
review.
Selected References:
Carpinelli RN, Otto RM (1998). Strength
training: single versus multiple sets. Sports Medicine 26, 73-84
Kraemer WJ (1997). The physiological basis
for strength training in American football: fact over philosophy. Journal of
Strength and Conditioning Research 11 131-142
Kraemer WJ, et al. (1997). Effects of
single versus multiple sets of weight training: Impact of volume, intensity
and variation. Journal of Strength and Conditioning Research 11, 143-147
Marx JO (1998). The effect of periodization
and volume of resistance training in women. Medicine & Science in Sports
& Exercise 30(5), S164 (Abstract 935)
Sanborn K, et al. (1998). Performance
effects of weight training with multiple sets not to failure versus a single
set to failure in women: a preliminary study. Presentation at the International
Symposium on Weightlifting and Strength Training, Helsinki, Finland, November
10-12, 1998
Retrieve the messages on the Sportscience
list for July 1997 by sending get sportscience log9707 to listproc=AT=stonebow.otago.ac.nz,
then search for HIT in the files you receive.
WHAT'S WORTH MONITORING?
Will
G Hopkins PhD, Physiology and Physical Education, University of Otago,
Dunedin 9001, New Zealand. Email: will.hopkins=AT=otago.ac.nz.
Sportscience 2(4), sportsci.org/jour/9804/brief.html#monitor, 1998 (743
words)
I posed this question recently on the
Sportscience mailing list. The original question focused on lab tests of
performance: I doubted whether these tests were precise enough to track the
small changes in performance that matter to an elite athlete. Field tests,
time trials, or competitive performances might be the only things worth
monitoring, or so I thought.
I have combined the original question and the replies
into a single document, which you can access from this link. Those who contributed material
have agreed to the publication of their messages. Here is a summary of the
most important points, drawn partly from the replies and partly from further
discussions with coaches and sport scientists.
- Regular systematic
monitoring by a dedicated team of support personnel is a key component
of some successful high-performance programs.
- Performance
itself needs to be monitored, but so do any factors that might impact
even indirectly on performance.
- Depending on the
sport, these factors include agility, anthropometry, biomechanics,
musculoskeletal status, nutrition, physiology, psychology, and skill.
- Where
appropriate, these factors need to be measured in sport-specific
ways.
- Rapid, direct
communication between athlete, coach, and sport scientists will help
in the identification and prioritization of strengths and weaknesses.
- The ability of a
test to track changes in an athlete's performance depends on the
variability in the athlete's performance between tests. If this
variability is greater than the variability in the athlete's
performance between competitions, the test won't be able to track
small but valuable changes in performance.
- For endurance
runners, several measures of anaerobic-threshold speed derived from
blood lactates in an incremental test have a typical variability
between tests of only ±1.5% (Pfitzinger and Freedson, 1998), which is
similar to the variability in competitive endurance performance of
world-class athletes. The anaerobic threshold is therefore well worth
monitoring. Another advantage of most anaerobic-threshold tests is
that the athlete does not have to make a maximal effort.
- Non-competitive
maximal lab tests or field time trials probably have more variability
between tests than the anaerobic threshold, so they aren't as useful.
- In one lab the
variability in maximum oxygen uptake between tests is ±2.0%
(Rivera-Brown et al., 1995). In most other places it ranges from ±3
to ±6%, or about ±2-4 ml/min/kg. This test is therefore precise
enough to identify athletes with endurance potential. Regular
monitoring of maximum oxygen uptake with a standardized protocol and
equipment may also help delimit moderate-large changes in an
athlete's endurance conditioning. In this respect it may complement
peak power and anaerobic threshold derived from a standardized
incremental test.
- An increase in the
anaerobic threshold by itself could indicate an improvement in fitness
or the onset of overtraining. But other measures will clarify the
situation (e.g. peak heart rate, peak lactate, effort, body mass,
skinfolds, mood state) and may even give you advanced warning of
overtraining.
- There is still no
worthwhile published practical hormonal or other blood test that can
be used to diagnose overtraining, let alone monitor for incipient
overtraining (Urhausen et al., 1998).
- But studies of
overtraining and performance enhancement are usually performed over a
restricted time frame, with insufficient pre- and post-testing to
delimit individual differences in the response to changes in training
or other intervention. When individual athletes are monitored over
several years, these individual differences may become apparent to the
coach and sport scientist, who can then optimize training and other
treatments for the individual.
- Even if some lab
tests aren't particularly reliable, the interactions between athlete,
coach, and sport scientist during administration of the tests are
worthwhile. Regular testing also motivates the athlete.
- Through experience
or formal research, some sport scientists have found new methods to
monitor athletes. Some of these methods may be too valuable for
publication, but in general they probably confer only a small advantage
to the athletes lucky enough to be monitored by them. Far more
important is regular systematic monitoring of the basics, which any
well-trained sport scientist can do.
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Pfitzinger P., Freedson PS (1998). The
reliability of lactate measurements during exercise. International Journal of
Sports Medicine 19, 349-357
Rivera-Brown AM, Rivera MA, Frontera WR
(1995). Reliability of VO2max in adolescent runners: a comparison between
plateau achievers and nonachievers. Pediatric Exercise Science 7, 203-210
[Coefficients of variation calculated from correlations and standard
deviations.]
Urhausen A, Gabriel HH, Kindermann W
(1998). Impaired pituitary hormonal response to exhaustive exercise in
overtrained endurance athletes. Medicine and Science in Sports and Exercise
30, 407-414
©1998
Edited by Chris Giles, Will
Hopkins, Mary Ann Wallace.
Webmastered by Chris Giles
and Will Hopkins
Published December 1998
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