Interrelationships of serum testosterone and free testosterone index with FFM and strength in aging men

Muscle mass and strength losses during aging may be associated with declining levels of serum testosterone (T) in men. Roy et al studied 262 men, aged 24-90 years, who had T and sex hormone-binding globulin sex hormone-binding globulin measurements, from which the free T index was calculated from serum samples collected longitudinally since 1963, total body fat mass and arm and leg fat-free mass by dual energy X-ray absorptiometry and arm and leg strength by dynanomometry.