Stance phase knee flexion helps "shave off" what part of the COM wave?

Stance phase knee flexion helps "shave off" what part of the COM wave?

• A. The bottom
• B. The top
• C. The side-to-side portion only
• D. The entire wave

Answer: (D)

During gait, the center of mass moves in a vertical wave as you step. When the stance knee flexes, the leg shortens and the body is cushioned more effectively, which slows and smooths how the mass rises and falls. This smoothing reduces the vertical amplitude of the center of mass throughout the entire cycle, so the knee’s stance flexion “shaves off” the whole vertical wave, not just a single portion. The effect on side-to-side motion isn’t the primary outcome here, so the emphasis is on the vertical trajectory across the full gait cycle.

During gait, the center of mass moves in a vertical wave as you step. When the stance knee flexes, the leg shortens and the body is cushioned more effectively, which slows and smooths how the mass rises and falls. This smoothing reduces the vertical amplitude of the center of mass throughout the entire cycle, so the knee’s stance flexion “shaves off” the whole vertical wave, not just a single portion. The effect on side-to-side motion isn’t the primary outcome here, so the emphasis is on the vertical trajectory across the full gait cycle.