Wright, G. A., DeLong, M., Sweeney, K., White, J., & Mikat, R. P. (2009). Creatine supplementation: Effects on leg power during repeat sprint running in collegiate football players. ACSM 56th Annual Meeting, Seattle, Washington. Presentation number 1911.

"American football is characterized by work:rest ratios of ~5 s of intense work with ~45 s recovery between plays. Although many research studies show that creatine loading is effective during repeat sprint activity on a cycle ergometer, the effectiveness of creatine loading has been less convincing during sprint running using sprint times as a performance measure. In studies that have shown no benefit during repeat sprint running tests, some have postulated that the increased body mass with creatine loading may compromise any metabolic benefit that may enhance sprint running performance."

This study determined the effects of creatine loading on repeat sprint running performance by measuring leg power on a loaded non-motorized treadmill during sprint running. On two occasions seven days apart, college football players (N = 20) participating in an off-season training program performed a repeat sprint test (RST) consisting of two sets of five maximal 5-second sprint runs on a non-motorized treadmill against a load equal to 15% of body mass. Recovery between sprints was 45 seconds, with 10 minutes between sets of sprints. Ss were familiarized with the repeat sprint test twice before the initial test. After the initial test, Ss were matched by average power produced during the repeat sprint test and separated into two supplementation groups: creatine (Cr 5 g x 4/d for 6 d) or placebo (PL same dosage of maltodextrin) in a double blind design. Percent body fat was determined before each test using the seven-site skinfold method.

Body mass increased in the Creatine group but not in the placebo group. Body fat did not change pre- to post-treatment for either group. Neither group showed a significant pre- vs. post-treatment difference in performance for peak power, average power, peak velocity, average velocity, or fatigue decrement for peak power, average power, peak velocity, or average velocity.

Implication. Sprint power and velocity during a repeat sprint test similar to the work:rest ratios for football are not affected by six days of creatine loading.

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