During the sprint start, the front leg has a greater influence on starting velocity and must exert force longer.

During the sprint start, the front leg has a greater influence on starting velocity and must exert force longer.

• A. Greater; Longer
• B. Less; Shorter
• C. Equal; Longer
• D. Greater; Shorter

Answer: (A)

The sprint start changes velocity mainly through impulse—the amount of momentum you impart to your body, which equals force multiplied by the time that force is applied. The front leg tends to stay in contact longer and provides a sustained forward push as the body moves from the block into a forward drive. That longer ground contact time, combined with effective projection mechanics, delivers a larger forward impulse to the center of mass, producing a higher starting velocity. If the front leg couldn’t apply force for that extended duration, the impulse would be smaller and the start would be slower. The other ideas don’t capture this link between longer force application and greater forward impulse as clearly.

The sprint start changes velocity mainly through impulse—the amount of momentum you impart to your body, which equals force multiplied by the time that force is applied. The front leg tends to stay in contact longer and provides a sustained forward push as the body moves from the block into a forward drive. That longer ground contact time, combined with effective projection mechanics, delivers a larger forward impulse to the center of mass, producing a higher starting velocity. If the front leg couldn’t apply force for that extended duration, the impulse would be smaller and the start would be slower. The other ideas don’t capture this link between longer force application and greater forward impulse as clearly.