Question

When a sprinter is attempting to perform an all-out sprint as seen in the panel above, in order to maximize their linear velocity they will flex the knee more during the initial portion of the swing phase than the knee would naturally flex during this phase. This alters the moment of inertia of the leg in a way that ultimately leads to increased linear velocity of the foot at the instant before foot strike. Describe the steps in this process. 1) Define moment of inertia, and describe how it changes as the knee goes through exaggerated flexion during the swing phase. 2) Describe what effect this change has on the angular velocity of the leg about the hip through the swing phase. 3) How is the angular impulse altered about the hip, and what relationship does this have to the change in angular velocity?

Answer 1