Resumen de Mechanical Muscle Function and Lean Body Mass During Supervised Strength Training and Testosterone Therapy in Aging Men with Low-Normal Testosterone Levels
Thue Kvorning, Louise L. Christensen, Klavs Madsen, Jakob Nielsen, Kasper D. Gejl, Kim Brixen, Marianne Andersen
Objectives: To examine the effect of strength training and testosterone therapy on mechanical muscle function and lean body mass (LBM) in aging men with low-normal testosterone levels in a randomized, double-blind, placebo-controlled 24-week study.
Design: Randomized, double-blind, placebo-controlled.
Setting: Odense, Denmark.
Participants: Men aged 60 to 78, with bioavailable testosterone levels of less than 7.3 nmol/L and a waist circumference greater than 94 cm were randomized to testosterone (50�100 mg/d, n = 22) placebo (n = 23) or strength training (n = 23) for 24 weeks. The strength training group was randomized to addition of testosterone or placebo after 12 weeks. Subjects performed supervised strength training (2�3 sets with 6- to 10-repetition maximum loads, 3 times per week).
Measurements: Testosterone levels, maximal voluntary contraction and rate of force development, and LBM were obtained at 0 and at Weeks 12 and 24 of the intervention.
Results: No changes in any variables were recorded with placebo. In the strength training group, maximal voluntary contraction increased 8% after 12 weeks (P = .005). During the following 12 weeks of strength training rate of force development increased by 10% (P = .04) and maximal voluntary contraction further increased (P < .001). Mechanical muscle function was unchanged in men receiving only testosterone for 24 weeks. LBM increased only in men receiving testosterone (P = .004).
Conclusion: Strength training in aging men with low-normal testosterone levels may improve mechanical muscle function, but this effect occurs without a significant increase in LBM. Clinically, only the combination of testosterone therapy and strength training resulted in an increase in mechanical muscle function and LBM.
