Muscle Oxidative Capacity in Vivo Is Associated With Physiological Parameters in Trained Rowers.

Purpose: The muscle oxygen uptake ( m V ˙ O 2 ) kinetics following exercise, measured by near-infrared spectroscopy, has been used as a functional evaluation of muscle oxidative metabolism. This study aimed to determine the m V ˙ O 2 off-kinetics and verify the relationship of the recovery rate of m V ˙ O 2 ( k ) with time-trial performance and different aerobic parameters in trained rowers. Methods: Eleven male rowers (age: 20 ± 3 years; V ˙ O 2 m a x : 4.28 ± 0.35 L·min -1 ) used a rowing ergometer to perform (I) an incremental test to determine the maximal oxygen uptake ( V ˙ O 2 m a x ) and peak power output (P peak ); (II) several visits to determine maximal lactate steady state (MLSS); and (III) a 2000-m rowing ergometer performance test. Also, one test to determine m V ˙ O 2 off-kinetics of the vastus lateralis muscle using a repeated arterial occlusions protocol. Results: The m V ˙ O 2 generated a good monoexponential fit ( R 2  = 0.960 ± 0.030; SEE = 0.041 ± 0.018%.s -1 ). The k of m V ˙ O 2 (2.06 ± 0.58 min -1 ) was associated with relative V ˙ O 2 m a x ( r = 0.79), power output at MLSS ( r = 0.76), and P peak ( r = 0.83); however, it was not related with 2000-m rowing performance ( r = -0.38 to 0.52; p > .152). Conclusion: These findings suggest that although not associated with rowing performance, the m V ˙ O 2 off-kinetics determined after a submaximal isometric knee extension may be a practical and less-exhaustive approach than invasive responses and incremental tests to assess the muscle oxidative metabolism during a training program.