1. Clasp your hands behind your head.
2. Keep your elbows straight.
3. Rotate your shoulders backward, squeezing your shoulder blades together.
4. Hold the stretch 10 to 15 seconds.
(For a greater challenge, look up while doing the stretch.)
Stretching makes your muscles and joints flexible, preventing injuries, and stopping your muscles from cramping. Flexibility also allows you to move your muscles through their full range of motion. That helps you jump higher, reach further, and run faster.