Fig. 4.

Average experimentally measured ground reaction forces and joint kinematics for subjects walking at four speeds (top) and running at four speeds (bottom) (N=5). Vertical and horizontal ground reaction forces per body weight (GRF/BW) were used to identify three consecutive joint cycles from heel strike to heel strike. Joint angles (in degrees) for the hip (flexion/extension), knee (flexion/extension) and ankle (dorsiflexion/plantarflexion), were calculated from marker data using an inverse kinematics algorithm and a musculoskeletal model scaled to each subject. These joint kinematics were prescribed during the forward simulations.