Effects of metacarpophalangeal joint position and finger joint movement speed on lumbrical muscle activity

Abstract

ObjectivesThe effect of metacarpophalangeal joint position and finger joint movement speed on lumbrical muscle activity remains unproven and was examined in this study. Material and methodsTwenty-four healthy adults performed flexion-extension movements of the index finger in different metacarpophalangeal joint positions (extension or flexion) and movement speeds (60, 120, 240, and 360 beats per minute). The activities of the first lumbrical, first dorsal interosseous, and extensor digitorum muscles were evaluated using surface electromyography, and compared with those during finger joint extension. ResultsThe metacarpophalangeal joint positions affected only lumbrical muscle activity, which was greater during extension. Further, finger movement speed affected the lumbrical and extensor digitorum muscle activities, which increased with increasing movement speeds. ConclusionThe present study suggests that position and movement speed can influence the lumbrical muscle activity during metacarpophalangeal joint extension. These findings may help expound lumbrical function and develop suitable strategies for inducing lumbrical muscle activity.