Creatine Supplementation in Endurance and Mixed-Sport Contexts: A Scoping Review of Performance, Recovery, and Body Composition.

抄録

Background/Objectives: Although creatine monohydrate is widely recognized as an effective ergogenic aid in strength and power sports, its role in endurance and mixed-sport disciplines remains less clearly established. This scoping review aimed to map the current evidence regarding the effects of creatine supplementation on performance, recovery-related outcomes, and body composition in endurance and mixed-sport contexts. Methods: A scoping review of randomized controlled trials published between 1996 and 2025 was conducted. Eligible studies evaluated creatine supplementation in endurance and mixed-sport contexts, including both sport-specific and broader exercise populations when the exercise protocol, testing model, or outcomes were relevant to endurance or mixed-sport performance, recovery, or body composition. A total of 38 studies met the inclusion criteria. Outcomes were categorized into exercise performance, biochemical markers related to recovery and exercise stress, and body composition parameters. Results: Creatine supplementation was most often associated with reported favorable changes in repeated-sprint performance and high-intensity power output, particularly during intermittent, sprint-based, or power-endurance tasks. Several studies reported favorable changes in sprint performance, peak power, or total work output relative to placebo or baseline values in cycling, swimming, rowing, and canoeing/kayaking protocols, although findings were not uniform across studies and not all favorable within-group changes were placebo-superior. Some studies also reported favorable changes in end-phase sprint capacity during prolonged exercise. Findings related to recovery were less consistent. Selected studies reported reductions in inflammatory markers, including C-reactive protein (CRP) and tumor necrosis factor α (TNF-α), whereas markers of muscle damage showed mixed responses. Most supplementation protocols involved a 5-7-day loading phase of 20 g/day, occasionally followed by a maintenance dose of 2-5 g/day. Small increases in total body mass were commonly observed, while evidence regarding fat-free mass and aerobic outcomes remained limited or inconsistent. Conclusions: Current evidence suggests that creatine supplementation may be most relevant in selected endurance and mixed-sport contexts involving repeated high-intensity efforts, sprint finishes, or power-endurance demands, rather than for endurance performance broadly. In contrast, evidence for recovery-related biochemical responses, body composition changes, and aerobic adaptations remains equivocal. Further well-controlled, sport- or context-specific, and field-based studies are needed to better clarify the role of creatine in endurance and mixed-sport exercise.