Leg extensor power and dehydroepiandrosterone sulfate, insulin-like growthfactor-I and testosterone in healthy active elderly people

We examined the association between quadriceps muscle function and serum le vels of dehydroepiandrosterone sulphate (DHEAS), insulin-like growth factor I (IGF-T) and testosterone in a group of healthy elderly people. Fifty-thr ee independent, community-dwelling elderly subjects (26 men and 27 women) a ged from 66 to 84 years volunteered to participate in the study. Physical a ctivity (PA) was evaluated by a questionnaire. Quadriceps maximal muscle po wer ((W)over dot(max)) and optimal shortening velocity (nu(opt)) were measu red on a friction-loaded non-isokinetic cycle ergometer. The (W)over dot(ma x) is expressed in relation to body mass (Wmax:kg, W. kg-l), and in relatio n to the mass of the two quadriceps muscles ((W)over dot(max/Quadr), W . kg (Quadr)(-1)). In women, when adjusted for age, anthropometric measurements and PA indices, IGF-I correlated significantly with (W)over dot(max/kg) (pa rtial correlation: r = 0.59; P = 0.001), (W)over dot(max/Quadr) (r = 0.58; P = 0.002) and nu(opt) (r = 0.53; P = 0.004), whereas DHEAS was correlated significantly with (W)over dot(max/kg) (r = 0.54; P = 0.003) and (W)(max/Qu adr) (r = 0.58; P = 0.002). No such correlation was found in men. These fin dings indicate that in healthy elderly women lower values for quadriceps mu scle (W)over dot(max) and nu(opt) are related, independently of age, anthro pometric measurements and PA indices, to lower circulating levels of DHEAS and IGF-I.