Effects of training and creatine supplement on muscle strength and body mass

The purpose of this study was to test the effect of creatine supplement on the size of the extra- and intracellular compartments and on the increase o f isokinetic force during a strength training-program. Twenty-five healthy male subjects (age 22.0 +/- 2.9 years) participated in this experiment. Sev en subjects formed the control-group. They did not complete any training an d did not have any dietary supplement. The eighteen other subjects were ran domly divided into a creatine- (n = 8) and a placebo-group (n = 10). They w ere submitted to a controlled strength-training program for 42 days followe d by a detraining period of 21 days. Creatine and placebo were given over a period of 9 weeks. The size of the body water compartments was assessed by bioimpedance spectroscopy and the isokinetic force was determined during a single squat by means of an isokinetic dynamometer. These measurements wer e completed beforehand, at the end of the training period, and after the de termining period. Both placebo- and creatine-group increased the isokinetic force by about 6% after the training period, showing that creatine ingesti on does not induce a higher increase of the force measured during a single movement. No change in body mass was observed in the control- and placebo-g roups during the entire experiment period while the body mass of the creati ne-group was increased by 2 kg (P < 0.001). This change can be attributed p artially to an increase (P = 0.039) in the body water content (+1.11), and more specifically, to an increase (P < 0.001) in the volume of the inter-ce llular compartment (+0.61). Nevertheless, the relative volumes of the body water compartments remained constant and therefore the gain in body mass ca nnot be attributed to water retention, but probably to dry matter growth ac companied with a normal water volume.