Most knee flexion during swing is produced how?

Most knee flexion during swing is produced how?

• A. By tibialis posterior
• B. Passively as a result of the flexing hip
• C. By active quadriceps contraction
• D. By intrinsic foot muscles

Answer: (B)

Most knee flexion in the swing phase happens passively as the hip drives the leg forward. When the hip flexes to move the thigh, the leg’s momentum and the knee’s passive joint properties allow the knee to bend without needing active contraction of the knee muscles. A knee flexion moment produced by the quadriceps would actually extend the knee, not flex it, so active quadriceps isn’t driving the bend. The foot- and ankle-focused muscles listed would not cause knee bending, they act elsewhere in the limb.

Most knee flexion in the swing phase happens passively as the hip drives the leg forward. When the hip flexes to move the thigh, the leg’s momentum and the knee’s passive joint properties allow the knee to bend without needing active contraction of the knee muscles. A knee flexion moment produced by the quadriceps would actually extend the knee, not flex it, so active quadriceps isn’t driving the bend. The foot- and ankle-focused muscles listed would not cause knee bending, they act elsewhere in the limb.