HARP

The psoas initiation of thigh swing (in red) increases knee flexion angle as seen with the supple (if not reflexively dampened). The heel is rising with the ball of the foot as the increasingly bearing pivot line. The ball of the foot leaves the ground (“toe off”) as the green line leaves the blue box. Clearly, nothing much happened new in that blue box. Pendulum inertia does the rest of the green line flexion (pendulum shin under a pendulum thigh). Hamstrings not only extend hips in weight lifting. In walking they dampen the swing of both femur (thigh) and lower leg (knee).