Creatine supplementation spares muscle glycogen during high intensity intermittent exercise in rats

Background

We investigated the ergogenic effects of betaine (B) supplementation on strength and power performance.

Methods

Twelve men (mean ± SD age, 21 ± 3 yr; mass, 79.1 ± 10.7 kg) with a minimum of 3 months resistance training completed two 14-day experimental trials separated by a 14-day washout period, in a balanced, randomized, double-blind, repeated measures, crossover design. Prior to and following 14 days of twice daily B or placebo (P) supplementation, subjects completed two consecutive days (D1 and D2) of a standardized high intensity strength/power resistance exercise challenge (REC). Performance included bench, squat, and jump tests.

Results

Following 14-days of B supplementation, D1 and D2 bench throw power (1779 ± 90 and 1788 ± 34 W, respectively) and isometric bench press force (2922 ± 297 and 2503 ± 28 N, respectively) were increased (p < 0.05) during REC compared to pre-supplementation values (1534 ± 30 and 1498 ± 29 W, respectively; 2345 ± 64 and 2423 ± 84 N, respectively) and corresponding P values (1374 ± 128 and 1523 ± 39 W; 2175 ± 92 and 2128 ± 56 N, respectively). Compared to pre-supplementation, vertical jump power and isometric squat force increased (p < 0.05) on D1 and D2 following B supplementation. However, there were no differences in jump squat power or the number of bench press or squat repetitions.

Conclusion

B supplementation increased power, force and maintenance of these measures in selected performance measures, and these were more apparent in the smaller upper-body muscle groups.