Fig. 2

Comparison of constrained model results and measurements a Tibio-femoral forces measured in vivo (light grey), tibio-femoral forces from the constrained model (between dashed lines), and the measured ground reaction forces (dark grey).The indicated range covers the mean ± 1SD as determined from repeated trials. b Comparison of the EMG data (recorded in 6 of the 9 patients) to the computed muscle forces from the constrained model, normalized by the maximum of each patient and activity