Table 1.

Summary of three optimization cases (with four subcases each—see Table 2) that varied how muscle model parameter values were calibrated and whether experimental contact forces were tracked. Calibrate indicates that muscle model parameter values were calibrated by the optimization, while Precalibrate indicates that precalibrated muscle model parameter values were taken from the corresponding Calibrate+Match subcase. Match indicates that experimental contact forces were matched by tracking three rather than one inverse dynamic knee load, while Predict indicates that experimental knee contact forces were predicted by tracking only one inverse dynamic knee load. F/E indicates flexion/extension, S/I superior/inferior, and V/V varus/valgus.

Optimization Case Abbreviation	Model Parameter Calibration	Contact Force Tracking	Knee Loads Tracked
Calibrate+Match	Yes	Yes	F/E moment S/I force V/V moment
Precalibrate+Predict	No	No	F/E moment
Calibrate+Predict	Yes	No	F/E moment