THE EFFECTS OF HYPERTROPHIC HEAVY STRENGHT TRAINING ON
BODY COMPOSITION
Juha Hulmi. University of Jyväskylä, Finland. Department of Biology of
Physical Activity. May 2005.
Introduction and methods
It is very well known that heavy strength training can induce substantial
skeletal muscle growth (hypertrophy). Not always but often it also
accompanies a body fat decrease.
It is difficult to compare studies because of tons of different training regimens
used, variations in subjects initial fitness status etc. Nevertheless, in this minireview
I reviewed 9 studies using women and 12 using men as subjects.
Inclusion criteria were: a) training was “hypertrophic” big muscle group training
using ~5-20 repetitions in multiple of sets per body and b) normal dynamic
constant external resistance training of 7-24 weeks in duration without using
extra pharmacological or nutritional supplements (e.g. creatine) and c) 2-4
workouts per week. Studies using professional body builders as subjects are
excluded. To decrease the effect of the variation in the duration of the studies
reviewed I averaged results as kilograms or percents to 4 week duration
(~month training).
Lean body mass (LBM) equals total body mass (TBM) without fat and
furthermore, total body mass equals lean body mass plus fat weight. Not all of
the lean body mass is skeletal muscle, but nevertheless it can be used as a
robust measure of skeletal muscle mass change during strength training.
Results and discussion
In the studies reviewed the average duration was 11.9 weeks (in men 10.9
and in women 12.6), frequency = 2.6 times a week (in men 2,7 and in women
2,6), repetitions per set = ~10, exercises per workout = 6.5 (in men 6.6 and in
women 6.4). In men the average four-week training increase in TBM was
0.40±0.33 (SD) kg. At the same time the LBM 0.56±0.46 kg and percent of
body fat (%fat) decreased 0.65 %. In women the increase in TBM was
0.11±0.32 kg and the increase in LBM 0.51±0.40 kg. Furthermore, in women
the %fat decreased 0.61 %. The lean body mass increase was also higher
than whole body mass increase indicating that in addition to the percent body
fat decrease the absolute body fat decreased also a little. Thus, muscle mass
increase is possible with concurrent decrease in body fat unlike the urban
legend says!
In conclusion: heavy hypertrophic strength training regimens reviewed in this
study increased lean body mass averagely ~0.5 kg and decreased
percent fat ~0.6% per one month training. In practice, the changes in lean
body mass and percent fat were same in men and in women. The research
clearly shows that significant increase in muscle mass is possible in both
women and men without simultaneous increase in body fat even without a
help of pharmacological substances!
References
Women:
Withers 1970
Brown & Wilmore 1974
Mayhew & Gross 1974
Wilmore et al. 1978
Hunter 1985
Staron et al. 1989
Staron et al. 1991
Staron et al. 1994
Häkkinen et al. 2001
Men:
Withers 1970
Fahey & Brown 1973
Misner et al. 1974
Coleman 1977
Wilmore et al. 1978
Gettman et al. 1979
Hunter 1985
Pierce et al. 1993
Staron et al. 1994
Häkkinen et al. 2002
Esmarck et al. 2001
Campos et al. 2002
