A systematic exploration of distal arm muscle activity and perceived exertion while applying external forces and moments.

The purpose of this study was to systematically explore and describe the response of selected hand and forearm muscles during a wide range of static force and moment exertions. Twenty individuals with manual work experience performed exertions in power grip, pulp pinch and lateral pinch grips. Electromyography (EMG) from eight sites of the hand and forearm, grip force as well as ratings of perceived exertion (RPE) were monitored as each participant exerted approximately 350 short (5 s) static grip forces and external forces and moments. As expected, strong relationships were found between grip force alone without other actions and muscle activation. When the hand was used to grip and transmit forces and moments to the environment, the relationships between grip force and muscle activation were much weaker. Using grip force as a surrogate for forearm and hand tissue loading may therefore be misleading.