The effects of dietary creatine monohydrate supplementation and resistance training in older men

In order to ascertain the effects of creatine monohydrate (CrH2O) supplementation on muscle mass and strength in older males, seventeen volunteers aged between sixty and eighty years were allocated to a creatine or a placebo group. Both groups took part in a training programme of the knee flexors and extensors of one leg only, consisting of knee flexion in a standing position and knee extension in a seated position. An adjustable, weighted cuff was used to provide resistance and subjects increased their weight reps and sets at their own discretion. The creatine group supplemented their training with CrH20 starting with a loading phase of 15 g CrH20 per day for 14 days and 3 g per day for the following 1 0 weeks. The placebo group took an equivalent amount of dextrose. The study was performed in a double-blind fashion. Strength changes were assessed using isokinetic dynamometry. Both isokinetic and isometric strength were tested. lsokinetic tests were done at 60°, 180° and 240° per second and isometric tests at 45°, 60° and 75°. Endurance was measured at the end of each testing session by means of five sets of 15 repetitions concentric knee extension and flexion at a speed of 180°/sec with 30 s rest between sets. Dual•energy X-ray absorptiometry (DEXA) scans were used to quantify total body lean mass and fat mass as well as limb segment mass changes, these were taken before and after the protocol. Serum creatinine was tested in order to quantify creatine uptake. There were no significant changes in the amount of serum creatinine for either group, nor were there any significant changes in body composition. Significant differences were found to occur in isometric and isokinetic strength, for both groups as a result of training over time. Isometric strength showed a significant increase over time overall (p≥0.05), but there was no statistical significance shown for any of the groups in respect to the baseline values. Subjects supplemented with CrH20 showed significant increases in isokinetic strength at the two slower velocities compared to baseline values. Subjects' endurance improved with training and the Cr group improved more than the PI group despite a slightly lower training volume. The major findings of this study were that CrH20 supplementation improved muscle function when combined with resistance training, particularly for repeated bout maximal activity in older males. The implications of this study are that this type of supplementation/training programme is well tolerated and would prove suitable for the more frail elderly population as well as individuals suffering from muscular degenerative disorders.