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,) performedwrist 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). (31)P 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.
RCT Entities:
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). (31)P 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.
Authors: J S Volek; N D Duncan; S A Mazzetti; R S Staron; M Putukian; A L Gómez; D R Pearson; W J Fink; W J Kraemer Journal: Med Sci Sports Exerc Date: 1999-08 Impact factor: 5.411
Authors: P Hespel; B Op't Eijnde; M Van Leemputte; B Ursø; P L Greenhaff; V Labarque; S Dymarkowski; P Van Hecke; E A Richter Journal: J Physiol Date: 2001-10-15 Impact factor: 5.182
Authors: Kylie K Harmon; Jeffrey R Stout; David H Fukuda; Patrick S Pabian; Eric S Rawson; Matt S Stock Journal: Nutrients Date: 2021-05-27 Impact factor: 5.717