Forearm muscle blood flow following eccentric exercise

Abstract

Exercise-induced muscle injury is associated with performing exercise that involves eccentric contractions. Although the effects of eccentric exercise on muscle injury are well known, previous studies investigating muscle blood flow following eccentric exercise have revealed conflicting results. The purpose of this study was to examine forearm muscle blood flow (FBF) during submaximal handgrip exercise following eccentric exercise of the elbow flexors. Seven healthy male subjects (27.9 ± 3.7 yrs; ± SD) performed two bouts (5 min) of dynamic handgrip exercise at 10% of maximal handgrip strength before and 48 hrs following damaging exercise (2 × 25 maximal eccentric contractions). Mean blood velocities (MBV) were measured continuously in the brachial artery using Doppler ultrasound. FBF was calculated using arterial diameters obtained at rest (Pre; 4.06 ± 0.34 mm: Post; 4.21 ± 0.30 mm, p>0.05). Despite a significant decrease (p<0.05) in maximal biceps brachii isometric strength from pre- (16.9 ± 3.6 kg) to post-injury (12.9 ± 4.6 kg), there was no difference in FBF at rest (Pre; 15.7 ± 4.1 ml/min: Post; 18.4 ± 5.4 ml/min) or at end exercise (Pre; 144.9 ± 34.7 ml/min: Post; 158.3 ± 28.4 ml/min) between conditions. It is concluded that muscle injury does not alter FBF during submaximal handgrip exercise suggesting that mediators involved in muscle injury and repair do not contribute to the regulation of muscle blood flow.