Application in Sports

The human leverage system is built for speed and range of movement rather than for force. Most muscles attach very close to the joint, giving short force arms and long resistance arms — the biceps force arm is only about 1 to 2 inches and the triceps force arm less than 1 inch — so great muscular strength is needed to move a load. A single sporting action uses several levers at once; throwing a ball, for example, works levers at the shoulder, elbow and wrist.

Longer levers impart more velocity. A tennis player hits harder with a straight-arm drive than with a bent elbow because the longer lever moves the racket head faster. Long levers produce more linear force and so help in sports such as baseball, hockey, golf and field hockey. Short lever arms, in contrast, give quickness — a baseball catcher brings the hand back to the ear for a fast throw, and a sprinter shortens the knee lever through flexion so the legs can swing through quickly.

Lever examples in sport