When the quadriceps muscles extend the knee, which component of the vector force produced by the muscle tends to produce movement?

Question

Quizplus · Accepted Answer

The perpendicular component of the vector force produced by the muscle is responsible for producing movement when the quadriceps muscles extend the knee. This is because the perpendicular component is the one that effectively contributes to the rotational movement around the joint, whereas the parallel component does not contribute to the movement in the same way.

When the Quadriceps Muscles Extend the Knee, Which Component of the Vector