Age-related hormonal adaptations, muscle circumference and strength development with 8 weeks moderate intensity resistance training

Abstract

Objectives: To examine the response of the endocrine system, strength development and muscle circumference to moderate-resistance training in younger and middle-aged men.

Material and methods: Two groups of men of similar activity background, but differing in age (Y: 21.2±2.2years and M: 49.7±2.1years) participated in an 8-week moderate-resistance training program. Blood sampling was obtained at rest before and after training for analysis of serum testosterone, growth hormone, cortisol and ACTH concentrations. One repetition maximum for the bench press (1RM(BP)) and squat (1RM(S)); thigh (TC) and arm circumference (AC) were also measured. Both groups underwent a 1-h standardized moderate-resistance training session (three series of 8 to 15RM; nine exercises with 1-3min rest between sets) three times a week for 8weeks.

Results: Both the Y and M groups gained significant improvements in 1RM(BP), 1RM(S), TC and AC (P<0.05). Growth hormone and testosterone concentration increased for both groups, while Y men increased greater than M men in resting posttraining testosterone concentration. With training the Y and M men demonstrated significant decreases in ACTH and cortisol concentrations.

Conclusion: These data indicate moderate-resistance training would lead to gains in maximal strength, muscle circumference and increases anabolic hormone secretion for M men and consequently promoting of health, improve daily life and delay negative effects with aging.