Title

Impact of creatine on muscle performance and phosphagen stores after immobilization

Document Type

Article

Publication Title

European Journal of Applied Physiology

Abstract

Purpose

This study investigated the effect of creatine (CR) supplementation during cast-immobilization to preserve skeletal muscle total work, power and intramuscular phosphocreatine (PCr) kinetics during dynamic exercise.

Methods

Twenty-five active individuals (24 ± 4 years,) performed wrist flexion exercise within a 1.9 Tesla superconducting magnet before and after 1 week of cast-immobilization. An incremental protocol to fatigue and two constant load (CL1 and CL2) exercise bouts were performed. While casted, participants consumed either 20 g day−1 of CR or a placebo (PLA). 31P magnetic resonance spectroscopy was used to quantify in vivo intramuscular PCr levels.

Results

No significant group × time interaction effects were found for work or power throughout all exercise bouts. Total work was significantly reduced over time in both groups (p = 0.049) during the incremental exercise bout. Work production in CL1 tended (p = 0.073) to attenuate in the CR group, compared to PLA. No changes were observed in CL2. Baseline PCr significantly decreased with casting in PLA (PRE: 26.6 ± 6.3 vs. POST: 22.5 ± 5.6 mM kg−1 wet muscle, p = 0.003). No change (p = 0.31) was observed in the CR group. Changes in work production were significantly correlated with changes in resting PCr in CR (r = −0.63, p = 0.021) but not PLA (r = −0.36, p = 0.26) group.

Conclusions

Results suggest decreases in short-term endurance may be due to alternations of PCr status and/or metabolism. More research is needed to fully determine the efficacy of CR supplementation during short-term immobilization.

DOI

https://doi.org/10.1007/s00421-015-3172-2

Publication Date

4-2015

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