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To investigate the effects of an acute bout of exercise on total and free insulin-like growth factor-I and insulin-like growth factor binding protein-3 plasma concentrations, 32 healthy elderly subjects (67-80 years, 16 men) performed a strength test, which consisted of two sets of 12 repetitions at 12-repetition maximum and four sets of 5 repetitions at 5-repetition maximum for horizontal leg press, seated chest press, and bilateral leg extension movements. Ten out of the 32 subjects served as time controls. Blood samples were drawn prior (08.30 h), immediately (10.30 h), and 6 h (16.30 hours) after the strength test in exercising and resting subjects. The 32 subjects were then randomly assigned to habitual physical activity or to an 8-week strength training program. After 8 weeks, both sedentary and trained groups underwent blood samplings under the above-mentioned conditions. The exercising group showed increased total and free insulin-like growth factor-I concentrations immediately (+17.7 and +93.8%, respectively), and 6 h (+7.5 and +31.2%, respectively) after the test, whereas no significant changes in insulin-like growth factor binding protein-3 concentrations were observed in either exercising or resting control groups. Strength training induced no significant changes in baseline insulin-like growth factor-I and insulin-like growth factor binding protein-3 concentrations. Trained and sedentary groups showed similar hormonal response pattern to the strength test, which consisted of increased total and free insulin-like growth factor-I concentrations. The data indicated that strength exercise can induce an early and sustained insulin-like growth factor-I release, in elderly subjects, regardless of their training status.

To investigate the effects of an oral creatine supplementation in older adults, 32 elderly subjects (67-80 years; 16 females, 16 males) were randomly assigned to four equivalent subgroups (control-creatine; control-placebo; trained-creatine; trained-placebo) based on whether or not they took part in an 8-week strength training programme and an 8-week oral creatine monohydrate creatine supplementation programme. The strength training programme consisted of three sets of eight repetitions at 80% of one-repetition maximum, for leg press, leg extension and chest press, 3 days a week. The 52-day supplementation programme consisted of 20 g of creatine monohydrate (or glucose) and 8 g of glucose per day for the initial 5 days followed by 3 g of creatine monohydrate (or glucose), and 2 g of glucose per day. Prior to and after the training and supplementation periods, body mass, body fat, lower limb muscular volume, 1-, 12-repetitions maxima and isometric intermittent endurance tests for leg press, leg extension and chest press were determined. In all groups, no significant changes in anthropometric parameters were observed. For all movements, the increases in 1- and 12-repetitions maxima were greater (P < 0.02) in trained than control subjects. No significant interactions (supplementation/training/time) were observed for the 1-, 12-repetitions maxima, and the isometric intermittent endurance, whatever the movement considered. We conclude that oral creatine supplementation does not provide additional benefits for body composition, maximal dynamical strength, and dynamical and isometric endurances of healthy elderly subjects, whether or not it is associated with an effective strength training.