Mechanical muscle function and lean body mass during supervised strength training
and testosterone therapy in aging men with low-normal testosterone levels.
Author(s): Kvorning T(1), Christensen LL, Madsen K, Nielsen JL, Gejl KD, Brixen K, Andersen
M.
Affiliation(s): Author information:
(1)Institute of Sport Science and Clinical Biomechanics, University of Southern
Denmark, Odense, Denmark. tkvorning@health.sdu.dk
Publication date & source: 2013, J Am Geriatr Soc. , 61(6):957-62
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.
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