The Effects of Creatine Supplementation on Exercise-Induced Muscle Damage

Abstract

This investigation evaluated the effects of oral creatine (Cr) supplementation on markers of exercise-induced muscle damage following high-force eccentric exercise in subjects randomly administered Cr or placebo (P) in a double-blind fashion. When injected, exogenous phosphocreatine has been shown to stabilize the muscle membrane in cardiac tissue and enhance recovery of strength and power following injury. Twenty-three men aged 18-36 years ingested either 20 g of Cr or P for 5 days. Criterion measures were maximal isometric force of the elbow flexors (MIF), range of motion (ROM) about the elbow, mid and distal arm circumference (CIR; to assess swelling), soreness with movement and palpation (SOR), and blood levels of creatine kinase (CK) and lactate dehydrogenase (LDH). Following the supplementation period, subjects performed 50 maximal eccentric contractions of the elbow flexors. Criterion measures were assessed pre-exercise, immediately postexercise, and for 5 days after exercise. Both groups experienced a significant loss of MIF and ROM (time effect, p < 0.05). There was a significant increase in CIR of the mid and distal biceps, SOR with movement and palpation, CK, and LDH (time effect, p < 0.05), indicating that there was significant muscle damage. However, there were no significant differences in any of the criterion measures between groups (group x time interaction term, p > 0.05). The pattern of change over the 6 days, in response to the eccentric exercise, was nearly identical between groups. These data suggest that 5 days of Cr supplementation does not reduce indirect markers of muscle damage or enhance recovery from high-force eccentric exercise.

Exercise-Induced Serum Enzyme Elevations Confounding the Evaluation of Investigational Drug Toxicity: Report of Two Cases in a Vaccine Trial

“…Prolonged creatine supplementation and repeated exercise were associated with increased CK-MM mRNA expression in one study, 18 but no effect on CK levels was observed in another. 19 It is unlikely that the single creatine dose had any effect on CK levels in Subject 18.…”

Suplementação De Creatina, Homocisteína E Estresse Oxidativo

“…Woo et al 3 relataram que a administração intravenosa de PCr previne a disfunção isquêmica ventricular em ratos, indicando melhora na integridade de membranas de células cardíacas. Rawson et al 51 sugeriram que a Cr pode atenuar danos oxidativos induzidos pelo exercício em cé-lulas musculares pela manutenção da homeostase energética mitocondrial. Autores sugerem que esses mecanismos estão ligados à redução da formação de EROs e podem ser indicativos de que a Cr detém efeitos antioxidantes indiretos 5 .…”

Creatine Supplementation and Athletic Performance

“…12,17,49,52,53 Cr supplementation generally has not been associated with improvements in endurance exercise performance, 16,29,52 or a reduction in muscle damage with high-intensity exercise. 44 Some of the discrepancies between study results may be attributable to differences in study design, including the sex, age, and training status of the subjects (untrained individuals versus elite athletes), the sport for which athletes were trained, Cr dose and duration of supplementation (3 days-12 weeks), and the exercise tests used to assess benefits. Furthermore, while many individuals derive benefit from Cr supplementation, others appear to be nonresponders, which may be explained by the variability in skeletal muscle accumulation of Cr with supplementation.…”