Fig. 6. Predicted versus observed mean vertical GRF. (A) Because the point of foot–ground contact shifts forward between heel-strike and toe-off, standing hip height, L, underestimates the effective length of the hindlimb, L'. (Adapted from Gottschall and Kram, 2005.) (B) Using L to predict vertical GRF via the LiMb model consistently overestimates vertical GRF (open squares), while L' provides a reasonably good fit (closed circles). Broken line indicates y=x.