Williams, C. J., & Harris, R. C. (2002). The effects of creatine supplementation on contractile responses of the human quadriceps. Medicine and Science in Sports and Exercise, 34(5), Supplement abstract 805.

This study examined the contractile responses of human quadriceps muscle to creatine supplementation. Males were divided into matched (maximum voluntary contraction (MVC) forces) creatine supplementation (N = 5) and placebo (N = 5) groups. Supplementation lasted seven days. The creatine dosage was 4 x 5 g with 5 g glucose per day. Maltodextrin was given in the same dose to the placebo group. Ss performed three maximum voluntary extension contractions of the dominant leg, each separated by one minute. During the contraction, 66% MVC was sustained until voluntary fatigue. Tetanic impulses were delivered at rest, immediately post fatigue, and after 15, 30, and 60 seconds of recovery. After a further 24 hours, Ss completed two further contractions, for 33% and 66% of the fatigue duration indicated the previous day.

Voluntary contraction/fatigue performance and relaxation time did not differ between the groups. The creatine group gained significant weight (1.4 kg).

Implication. Creatine supplementation did not affect voluntary isometric contractions of the quadriceps.

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