Fig.1.

A typical plot of the linear relationship between impulses resulted from vertical component of the ground reaction force (F_Z) as well as body gravity and the resulting change in hip height during single stance phase from recovery liftoff (L-LO) to its touchdown for a gait-slip fall trial. The experimental results (solid line) are well fitted by a straight line (dashed line). The impulse is calculated as ${\int }_{t_{L-LO}}^t[F_Z\left(t\right)-bw]dt$, where bw represents body weight. The change in hip height is with respect to hip height at L-LO. The vertical impulse is normalized to bw, and change in hip height normalized to body height, bh.