Muscle force recovery in relation to muscle oxygenation


The aim of this study was to investigate the relative contribution of human muscle reoxygenation on force recovery following a maximal voluntary contraction (MVC). Ten athletes (22˙9 ± 4˙0 years) executed a plantar-flexion sequence including two repeated MVCs [i.e. a 30-s MVC (MVC30) followed by a 10-s MVC (MVC10)] separated by 10, 30, 60, 120 or 300 s of passive recovery. A 10-min passive recovery period was allowed between each MVC sequence. This procedure was randomly repeated with two different recovery conditions: without (CON) or with (OCC) arterial occlusion of the medial gastrocnemius. During OCC, the occlusion was maintained from the end of MVC30 to the end of MVC10. Muscle oxygenation (Near-infrared spectroscopy, NIRS, [Hbdiff]) was continuously measured during all MVC sequences and expressed as a percentage of the maximal changes in optical density observed during MVC30. Maximal Torque was analysed at the start of each contraction. Torque during each MVC10 was expressed as a percentage of the Torque during the previous MVC30. Torque recovery was complete within 300 s after MVC30 during CON (MVC10 = 101˙8 ± 5˙0%); 88˙6 ± 8˙9% of the Torque was recovered during OCC (P = 0˙005). There was also a moderate correlation between absolute level of muscle oxygenation and Torque (r = 0˙32 (90% CI, 0˙09;0˙52), P = 0˙02). Present findings confirm the role of human muscle oxygenation in muscular force recovery during repeated-maximal efforts. However, the correlation between absolute muscle oxygenation and force level during recovery is only moderate, suggesting that other mechanisms are likely involved in the force recovery process. © 2012 The Authors Clinical Physiology and Functional Imaging © 2012 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

Clinical Physiology and Functional Imaging