The Effects of Creatine Monohydrate Supplementation on Recovery from Eccentric Exercise-Induced Muscle Damage: A Double-Blind, Randomized, Placebo-Controlled Trial Considering Sex and Age Differences

<b>Background/Objectives</b>: In this study, we aimed to examine the effect of creatine monohydrate (CrM) supplementation on recovery from eccentric exercise-induced muscle damage (EIMD) in diverse populations, including different sexes and age groups. EIMD decreases maximal voluntary contraction (MVC), restricts the range of motion (ROM), and increases muscle stiffness and delayed-onset muscle soreness, all of which negatively impact athletic performance. Therefore, developing effective recovery strategies is essential. <b>Methods</b>: A double-blind, randomized, placebo-controlled trial was conducted with 40 healthy male and female participants. After 33 days of supplementation with either CrM or placebo (crystalline cellulose), the participants performed eccentric exercises. Recovery indices, including MVC, muscle stiffness, subjective muscle extensive soreness, fatigue, and upper arm circumference, were measured at baseline, immediately after exercise, 48 h post-exercise, and 96 h post-exercise. <b>Results</b>: The creatine supplementation group (CRE) demonstrated a significantly quicker recovery of MVC than the placebo group (PLA). Furthermore, reductions in shear modulus and muscle fatigue were observed in the CRE group. Notably, females in the CRE group exhibited a significant suppression of post-exercise edema, suggesting a sex-specific response. <b>Conclusions</b>: These findings indicate that CrM supplementation may enhance recovery from EIMD, contributing to the maintenance of muscle function and the reduction of discomfort after exercise. CrM has the potential to serve as a practical nutritional strategy to promote recovery, not only for athletes, but also for a broader population.