In recent years, the near-infrared spectroscopy (NIRS) technique has revolutionised the way in which muscle oxidative metabolism is non-invasively measured during the natural execution of movements. Therefore, the NIRS technique has been increasingly utilised in research and clinical laboratories around the world to investigate the dynamic changes in muscle oxygenation during exercise. The book presents a comprehensive understanding of the NIRS technique, research applications, and advanced analysis methods used to measure muscle oxygenation during voluntary and electrically evoked exercise. The book should be especially useful to exercise physiologists and clinicians, or anyone else who may be considering utilizing NIRS to better understand the physiology of skeletal muscle during exercise.