The influence of wrist position on different types of pinch strength.

This study examines the effects of different wrist positions on maximum voluntary (MVC) pinch strength. Peak MVC forces of 30 male adults were measured for lateral, chuck, pulp-2 and pulp-3 pinches, each in five wrist positions-natural, radial deviation, ulnar deviation, dorsiflexion and palmar flexion. The results showed that all the deviated wrist positions degraded pinch strength, with palmar flexion having the greatest effect and radial deviation the least. Strength degradation ranged from 14% to 43%, depending on wrist position and type of pinch. The lateral pinch was less affected than the others. Biomechanical explanations are offered for these measurements, and implications for work and tool designs are discussed.