An investigation of finger pull strengths

This paper describes a study to investigate the nature of pull strength with the fingers. Three types of pulls, distinguished by the type of pinch grip used, were investigated. The experiment was performed in two stages, using different subjects (36 male adults in Stage I and 34 in Stage II). The results indicated that finger pull strength depended on the type of pinch grip used but not on the direction of pull (in the saggital plane) nor on hand laterality. Pull forces with the lateral pinch grip were 1.6 times as strong as with the chuck pinch grip, which was, in turn, 1.5 times as strong as with the pulp pinch grip. Ergonomic design applications suggest a larger pinch handle and workspace to accommodate the lateral grip. Finger pull strength could not be predicted very accurately from pure pinch strengths or anthropometric dimensions accurately enough to be of value to designers, even though there were many statistically significant pairwise correlations.