Contributions of posture and grip force to forearm EMG during grip tasks

The intricate anatomical nature of the forearm complicates the relationship between posture, muscle activity and the resultant external force produced during manual hand tasks. This thesis explored forearm muscle response to various postures and grip exertion levels, along with some important technical issues which may confound the interpretation of electromyographic (EMG) studies of the forearm. This was accomplished through two major studies, which examined: (1) the effects of forearm rotation on the magnitude of crosstalk in forearm surface EMG; and (2) the effects of forearm and wrist posture on forearm muscle loading during various levels of grip exertion.

The first study evaluated EMG crosstalk in the forearm, under several conditions, between electrode pairs placed circumferentially around the proximal forearm muscle bulk, using the cross-correlation function. This included the investigation of four levels of pinch and grasp exertions in three forearm postures.

The second study investigated the response of specific finger and wrist flexor and extensor muscles to different postures with varying grip force exertions, again using an EMG protocol. (Abstract shortened by UMI.)