Relationships between changes in oxygenation during exercise and recovery in trained athletes

The purpose of this study was to investigate the relationships of rate of deoxygenation determined using near-infrared spectroscopy (NIRS) during isometric contraction exercise (Rate(deoxy)) with maximal muscle strength, muscle thickness and muscle oxidative capacity of knee extensors in eight well-trained male athletes. The subjects performed sustained isometric extension at 30% and 50% of the maximal voluntary contraction (MVC) load for 10s and 30 repetitive maximal isokinetic knee extensions. Rate(deoxy) in the final 5 s of 30% MVC was negatively correlated with maximal muscle strength, muscle thickness of knee extensors and the half-time of deoxygenation recovery (T1/2) determined by NIRS after 30 repetitive maximal isokinetic contractions, defined as muscle oxidative capacity. The results suggest that Rate(deoxy) during submaximal isometric contraction reflects muscle aerobic capacity.