Creatine Supplementation On Youth Soccer Player Body Weight And Running Anaerobic Sprint Performance Test-Associated Metrics

Creatine supplementation commonly increases intracellular water and/or lean mass-associated weight gain and concomitantly improves short-term, high-intensity performance such as repeated sprint ability. Research in this regard is both generally sparse but specifically more so in younger soccer athletes. PURPOSE: To determine the effect of 28 days of creatine monohydrate supplementation on body weight and running anaerobic sprint performance (RAST) time in youth soccer players. METHODS: Sixteen male youth soccer players were randomized in double-blinded fashion to either 28 days of creatine monohydrate supplementation (CRE; 15.9±0.35y) or an equivalently-dosed dextrose (PLA; 15.5±0.54y; 0.3g/kg/d for the first seven days, followed by 0.03g/kg/d for the remaining 21-day period). Subjects maintained their typical diet and training routines throughout the study. Subjects measured their body weight (BW) and performed RASTs both prior to (PRE) and following (POST) supplementation, consisting of 10 second rest intervals between six maximal 35m runs. RAST time and associated (mean [mP] and peak [pP]) power was determined via a Speed Test FIT CEFISE photocell system. Changes from PRE-to-POST BW were analyzed using an independent samples t-test. Changes from PRE-to-POST RAST time (∆Time), as well as mP (∆mP) and pP (∆pP) were assessed by separate two-way (condition [CRE, PLA] x RAST trial number [1, 2, 3, 4, 5, 6]) repeated measures ANOVA. Statistical analyses were performed at a p<.05 significance level. RESULTS: Analyses revealed a significant change in BW (p>0.001; Cohen’s D=0.409) in CRE that was not observed in PLA (1.09±0.314kg vs -0.08±0.259kg, respectively). There was no significant main condition, RAST trial number, nor interaction effects for ∆Time, ∆mP, or ∆pP (p>0.05 in all cases). CONCLUSION: Creatine supplementation did not meaningfully enhance RAST-associated sprint times or associated power metrics in youth soccer players. Results corroborate previous literature via increased body weight in youth soccer athletes, but the source of this weight is unknown (intracellular water, lean mass, fat mass, etc.). Future research should continue to elucidate the impact of creatine in this demographic by employing a standardized training protocol to further eliminate possible extraneous variables.