Optimum tool handle diameter for a cylinder grip.

The ideal diameter for a tool handle for males and females has been determined using an existing biomechanical model of the hand validated in previous works. The model estimates a 33-mm optimum diameter tool handle for the general population (males and females). When the optimum diameter for a tool handle is selected, the muscles exert the minimum force needed to hold the tool and perform gripping activities. Optimal handle design reduces the force required for gripping a tool, protects the underlying joint structures, and reduces the risk of developing cumulative trauma associated with repetitive task requiring high grip forces and awkward postures. This article provides a design parameter for optimal tool diameter to aid the therapist in the selection of assistive devices, built-up handles, or for the fabrication of a tool handle.