The document discusses the principle of summation of forces, where maximum force is generated by recruiting muscles sequentially from largest to smallest. It provides examples of how this principle applies to specific athletic skills like kicking a football, serving a tennis ball, and serving a volleyball. The volleyball serve example describes how core, hip, leg, shoulder, arm, and hand muscles are recruited in order from trunk to extremities to transfer force from the body to the ball.

1. Summation of Forces

3. Summation of Forces Summation of Forces 2. Sequential and simultaneous force 1. Heavest and slowest body parts move first. Smaller, faster body parts move last 3. Use as many body parts as possible to get maximum force

7. Using the photos below and your knowledge of force summation, explain how force is applied in a volleyball serve.