Static analysis of nippers pinch.

The purpose of the study was to present a method for the assessment of finger joint torques in two-fingered precision grips. The static analysis of various grips is important for the analysis of the mechanics of a human hand and the functional evaluation of grasping. We have built a grip-measuring device assessing the endpoint forces of two-oppositional grips. Through the simultaneous use of an optical measuring system and the grip-measuring device, the finger positions and the grip force acting on the object were obtained. A recursive computational method was used within the proposed static model of the finger to calculate the finger joint torques. In the paper a three-dimensional static model of the grip is presented and the calculated finger joint torques are shown. The repeatability within subject is analyzed for the assessed grip force and finger joint torques. The estimated joint torques corresponds to the amount of load on the finger joints during the isometric muscle contraction in nippers pinch.