Abstract
Muscle oxygen saturation, measured through near-infrared spectroscopy, has emerged as a valuable marker for monitoring exercise intensity, physiological adaptations, and sports performance. This narrative review examines the physiological foundations of muscle oxygen utilization, the principles and validity of near-infrared spectroscopy technology, and its applications in various training modalities, including endurance, interval, and strength-based exercises. Portable near-infrared spectroscopy devices enable real-time, non-invasive assessment of muscle oxygen dynamics in field settings, providing coaches and athletes with precise information on oxygen delivery, consumption, and recovery kinetics. Evidence indicates that muscle oxygen saturation is closely related to metabolic thresholds, lactate accumulation, and internal load, making it a reliable parameter for individualized training prescription and performance optimization. Furthermore, muscle oxygen saturation monitoring offers promising perspectives for strength training, injury prevention, and rehabilitation strategies. By integrating muscle oxygen saturation into performance assessment, sports scientists and practitioners can bridge the gap between laboratory-based physiology and applied field practice, supporting both performance enhancement and athlete health.
Cite this article as: Bonilla, A. A., Sepúlveda, R. Y., & Valverde, D. R. (2026). Muscle oxygen saturation as a marker of sports performance. Research in Sports Science, 2026, 16, 0101, doi: 10.5152/rss.2026.25101