The effect of elbow position and grip span on isometric grip strength and force distribution of fingers.

Injuries to the hand, lower arm, and shoulder are often attributed to inappropriate use or poor design of hand tools. Isometric grip, performed with the angled handles of pliers was investigated in this study. For this thesis, three factors were studied. They were grip type (traditional and reversed grip), elbow position (0\sp\circ, 30\sp\circ, 60\sp\circ, 90\sp\circ, and 120\sp\circ), and grip span (50, 60, and 70 mm). The resultant forces between the jaws of the pliers and finger forces were measured under each condition. The purpose of this study was to evaluate the effect of elbow position and grip span on grip strength and force distribution across the fingers. The results showed that elbow position, grip span and grip type have significant effects on resultant force and finger force. The forces were statistically higher at the fully extended elbow position than at the 30\sp\circ, 90\sp\circ and 120\sp\circ elbow positions, and the resultant force was higher at the 60\sp\circ, 30\sp\circ, and 90\sp\circ positions than at the 120\sp\circ position. Regardless of elbow positions and grip type the optimal grip span was found to be 50 mm and forces decreased as grip span increased. The resultant force obtained in a traditional grip exceeded the force obtained in a reversed grip. Also, the finger force varied according to elbow position, grip span and grip type. The influences of these factors also varied according to fingers. Interactions between grip span and grip type were found in index and ring fingers. (Abstract shortened by UMI.)Dept. of Industrial and Manufacturing Systems Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1997 .C4255. Source: Masters Abstracts International, Volume: 37-01, page: 0334. Thesis (M.A.Sc.)--University of Windsor (Canada), 1997