Warming-up before beginning dance is a crucial step in the process. It is key to do this to prevent injury and keep your body in peak condition. In addition to preventing injury, an effective warm-up will get the blood flowing, improve flexibility, and will give dancers some mental time to prepare for class. 

Stretching enables you to loosen the muscles and gets your whole body better prepared for dance classes and performances. Because your muscles are warmed up, you're putting less energy into your joints and more into your movements.