THE EFFECT OF MEASUREMENT ANGLE ON APPROXIMATIONS OF MAXIMUM JOINT TORQUE

The purpose of this study was to investigate the underestimation of maximum knee joint torque using a single joint-angle position for a variety of realistic torque-angle curves. The maximum force production capability of the knee flexors and knee extensors was modelled using literature-based parameters to define a quadratic torque-angle relationship. Model parameters were varied within a normative range and simulated measured torque was compared to true peak torque (model) for a series of commonly tested joint angles. Measurements furthest from the optimal angle for maximum strength were associated with underestimated torques that were 96% and 80% lower than true peak torque. Therefore, it is essential that knee joint torque is measured as close to the optimal angle as possible when attempting to determine maximum strength capability using a single discrete measurement