Jim Carpentier is a certified strength and conditioning specialist, New Jersey-licensed massage therapist and a health/fitness writer. He currently serves as associate health and wellness director at the Greater Morristown YMCA in Cedar Knolls, N.J.
Never add more than 10% of your body weight to a sled when performing resisted sprints, and avoid running 10% slower than your best time. Greater than 10% changes your body position, technique and sprinting mechanics, resulting in negative outcomes.
