Creatine monohydrate supplementation on lower-limb muscle power in Brazilian elite soccer players

Abstract

Background: Studies involving chronic creatine supplementation in elite soccer players are scarce. Therefore, the aim of this study was to examine the effects of creatine monohydrate supplementation on lower-limb muscle power in Brazilian elite soccer players (n = 14 males) during pre-season training.

Findings: This was a randomized, double-blind, placebo-controlled parallel-group study. Brazilian professional elite soccer players participated in this study. During the pre-season (7 weeks), all the subjects underwent a standardized physical and specific soccer training. Prior to and after either creatine monohydrate or placebo supplementation, the lower-limb muscle power was measured by countermovement jump performance. The Jumping performance was compared between groups at baseline (p = 0.99). After the intervention, jumping performance was lower in the placebo group (percent change = - 0.7%; ES = - 0.3) than in the creatine group (percent change = + 2.4%; ES = + 0.1), but it did not reach statistical significance (p = 0.23 for time x group interaction). Fisher's exact test revealed that the proportion of subjects that experienced a reduction in jumping performance was significantly greater in the placebo group than in the creatine group (5 and 1, respectively; p = 0.05) after the training. The magnitude-based inferences demonstrated that placebo resulted in a possible negative effect (50%) in jumping performance, whereas creatine supplementation led to a very likely trivial effect (96%) in jumping performance in the creatine group.

Conclusions: Creatine monohydrate supplementation prevented the decrement in lower-limb muscle power in elite soccer players during a pre-season progressive training.

Keywords: Athletes; Dietary supplement; Football; Jumping; Team sports.

Figure 1

Illustration of the training load (as determined by the RPE method [19]) progression throughout the intervention period.

Figure 2

Jumping performance before (Pre) and after 7 weeks (Post) of either creatine (n = 7) or placebo (n = 7) supplementation in soccer players during pre-season training. Panel A: individual data. Panel B: mean ± standard deviation of delta. No significant difference between groups across time (group x time interaction) was observed (p = 0.23).