To determine whether a total body, heavy resistance, strength training (ST) program
can significantly increase muscle strength and hypertrophy without muscle cell disruption
and soreness in older men, 35 sedentary male subjects between the ages of 50 and 69
years of age (60 ± 5, X ± SD) were studied. Twelve served as inactive controls. Muscular
strength, cross-sectional muscle area, serum creatine kinase (CK) activity and perceived
soreness were assessed before and after a 16 wk heavy resistance ST program. The ST
program resulted in a 43 % increase in muscular strength (p < 0.001), and a 7.2 %
increase in midthigh muscle area (153 ± 24 vs 164 ± 23 cm2, p < 0.001). There were
no significant changes in strength or muscle area in the inactive control group. Peak
serum CK levels were approximately twofold above baseline (278 ± 175 vs 133 ± 88 U/I,
p < 0.01) 8 h after the first regular training session. At the end of training, the
peak rise in CK levels was also reached 8 h after exercise, but was reduced substantially
at the same absolute (p < 0.01) and relative resistance loads (p < 0.01) compared
to the first training session. Muscle soreness after exercise was only occasionally
reported at the beginning of training and was almost nonexistent after training. These
results indicate that middle-aged and older men can safely participate in a total
body strength training program, intense enough to produce substantial increases in
muscle strength and hypertrophy, without promoting muscle soreness or significant
muscle cell disruption. Furthermore, the risk of muscle cell disruption during acute
resistive exercise is reduced at the end of a strength training program in older individuals
similarly to that reported in younger individuals.
Key words
Weight training - aging - muscle mass - muscle injury - creatine kinase
