Evaluation of Handle Diameter in Maximum Horizontal and Vertical Torque Tasks

Abstract

The effects of handle diameter (25∼50mm) and handle orientation (horizontal and vertical) on the subjective comfort, maximum torque performance, total finger force, and efficiency of flexor and extensor muscle activity were evaluated in this study. A force glove system containing 16 force sensors was used to measure finger forces, and surface electromyography was used to investigate muscle activities during torque tasks. Overall 35∼45mm diameter handles were rated as most comfortable. The average torque outputs were highest with the 45 and 50mm diameter handles in both orientations. Torque output exhibited a positive non-linear correlation with handle diameter, whereas total finger force showed an inverse relationship with handle diameter. The positive non-linear correlation between torque and handle diameter was explained by the relationship between handle diameter, total finger force, and coefficient of friction. Muscle activities and efficiencies of flexor and extensor muscles were also investigated in this study.