Flexibility prevents injury, according to a 2003 study. The Impact of Stretching on Sports Injury Risk: A Systematic Review of Literature.  

1. Stretching before any activity creates muscle and joint laxity

2. Possibly more important than stretching, warming up promotes blood flow to muscles and prepares the body for vigorous exercise by increasing muscle elasticity, thus decreasing the likelihood of tearing a muscle

3. Strength training lengthens your muscles and develops strength and endurance, which combat the weakness and fatigue that make muscles more prone to injury and tear