If men in their sixties start doing strength training they don’t build up just as much muscle mass as men in their thirties do. But we shouldn’t exaggerate the difference – people in their sixties who start doing strength training are perfectly capable of developing bigger and stronger muscles. This was shown in a study that American sports scientists published in the Journal of Applied Physiology in 1999.
The researchers did an experiment with two groups of men. The men in one group had an average age of 30 and in the other 62. All of the participants were fit but had never done weight training before.
The researchers got all the men to do strength training in the same way for a period of 10 weeks.
The concentration of free testosterone while resting rose in the thirty-year-olds as the study progressed over the ten weeks. That did not happen to the sixty-year-olds.
The sixty-year-olds’ cortisol concentration while resting declined as the experiment progressed. That didn’t happen to the thirty-year-olds.
The IGF-1 concentration in the blood was higher in both groups immediately after a training session. The increase in this hormone was higher in the thirty-year-olds.
So thirty-year-olds’ and sixty-year-olds’ hormonal reactions to strength training are different. But both groups built up muscle mass during the 10 weeks. The increase in muscle mass was bigger in the thirty-year-olds than in the sixty-year-olds however.
MCSA = total thigh muscle cross-sectional area.
The increase in strength was the same in both groups.
The most surprising finding that emerged from the study is not that thirty-year-olds start synthesising more testosterone and IGF-1 than sixty-year-olds. Nor is it so surprising that the younger men produce more extra IGF than the older men after a workout. What is surprising is that, despite the clear hormonal differences, the effect of strength training on muscle mass and strength is so similar in both groups.
Effects of heavy-resistance training on hormonal response patterns in younger vs. older men.
To examine the adaptations of the endocrine system to heavy-resistance training in younger vs. older men, two groups of men (30 and 62 yr old) participated in a 10-wk periodized strength-power training program. Blood was obtained before, immediately after, and 5, 15, and 30 min after exercise at rest before and after training and at rest at -3, 0, 6, and 10 wk for analysis of total testosterone, free testosterone, cortisol, growth hormone, lactate, and ACTH analysis. Resting values for insulin-like growth factor (IGF)-I and IGF-binding protein-3 were determined before and after training. A heavy-resistance exercise test was used to evaluate the exercise-induced responses (4 sets of 10-repetition maximum squats with 90 s of rest between sets). Squat strength and thigh muscle cross-sectional area increased for both groups. The younger group demonstrated higher total and free testosterone and IGF-I than the older men, training-induced increases in free testosterone at rest and with exercise, and increases in resting IGF-binding protein-3. With training the older group demonstrated a significant increase in total testosterone in response to exercise stress along with significant decreases in resting cortisol. These data indicate that older men do respond with an enhanced hormonal profile in the early phase of a resistance training program, but the response is different from that of younger men.
PMID: 10484567 [PubMed – indexed for MEDLINE]