Set up for propulsion begins at the end of terminal swing as the hip joint flexes, creating the maximal range of motion for the hip extensors to accelerate through and produce force. As the hip extensors change from reciporatory inhibitors to primary muscle movers, the lower extremity is brought back toward the ground, although aided greatly by the stretch reflex and gravity. Footstrike and absorption phases occur next with two types of outcomes. This phase can be only a continuation of momentum from the stretch reflex reaction to hip flexion, gravity and light hip extension with a heel strike, which does little to provide force absorption through the ankle joint. With a mid/forefoot strike, loading of the gastro-soleus complex from shock absorption will serve to aid in plantar flexion from midstance to toe-off.