A Preliminary Investigation on the Grip Force Applied on a Cylindrical Handle

Hand grip force is an important factor for risk assessment of hand musculoskeletal disorders. Grip strength is also one of the important indices for the diagnosis of hand disorders such as hand-arm vibration syndrome and carpel tunnel syndrome. Therefore, a considerable number of studies on grip force or strength have been reported. However, it remains an important issue how to quantify the grip force or strength. Conventionally, the grip force is measured using a handle that measures the applied force in two opposite directions in the grip action. However, it has been demonstrated that the grip force applied on a cylindrical handle is not uniformly distributed in each orientation of the hand [1]. Therefore, the grip force measured in a specific direction may not be an accurate measure of the grip effort. Alternatively, the total grip force has been proposed to serve as the grip measure [2]. The major objectives of this study are as follows: (i) to develop a cylindrical instrumented handle that can be used to perform the measurement of the total grip force and to characterize its distribution around the handle; (ii) to estimate the principle grip force and direction; and (iii) to investigate the relationship between the total grip force and that measured on a Jamar handle.