Hand Grip Force Among Forest Workers

Abstract

Maximal voluntary compression (MVC) of hand grip was measured among 177 forest workers. The occupational history and symptoms of upper limbs were surveyed. MVC was age and exposure dependent and correlated significantly with history of diminished hand grip force, numbness, vibration induced white finger (VWF), and pain in the upper limbs and neck. Asymmetric MVCs between the right and left hand was found in 46 forest workers. In an analysis of covariance, the most significant factor for reduced MVC was asymmetry of MVC followed by exposure to hand-arm vibration. The interaction of age and exposure was almost statistically significant. These factors explained 46.9% of the variation of MVC in the right hand and 35.4% in the left hand. In the model neither neck, NWF, numbness nor pain in the upper limb explained more significantly the variance in MVC. The study confirms the relationship of reduction in MVC and history of diminished hand grip force. This effect was ascribed to chain saw vibration confounded by ageing and certain overstrain symptoms of the upper limbs.