An algorithm for directly fitting a moment-angle-angular velocity model to maximum voluntary muscular moments measured with an isokinetic dynamometer

Joint kinematics influence maximum voluntary muscular moment of force about a joint, and can thereby have substantial effects on available muscle moment during dynamic activities. A model of maximum voluntary muscle moment as a function of joint angle and angular velocity has been described previously. Originally, a computational optimization approach was used to fit this model to muscle moment data collected using an isokinetic dynamometer. To make this model more practical and accessible, an algorithm was developed to directly determine the model parameters without requiring optimization. This algorithm was compared with the optimization method for fitting measured muscle moment data from six different lower limb exertions in 14 healthy adults. Both methods produced models that fit the measured moment data reasonably well(r $^{2}$ typically > 0.75), and the direct calculation method reduced r $^{2}$ only slightly compared to optimization (by an average of 1.14%). The direct calculation algorithm presented here may be preferable to the optimization approach used previously, as it displays comparable performance but requires less time and expertise to employ.