There are 3 parts to a training session - the warm-up, the main activity and then after, the cool down. Warming up and cooling down are the one of the most important aspects of performing to your bodies maximum potential. Prior to your workout, warming up is essential. It, not only as I have mentioned, improves your performance, it also prevents injury to the muscles. Often when people warm up for their activity they either don't stretch the right muscles needed for their sport or they don't do the stretch properly. In most cases a bit light aerobic work is endured at intervals throughout your warm up. Warm-ups can be directly related to the session you are going to do - use of sporting movements, or indirectly related - general movements. The main purpose of a warm up is to increase body temperature and heart rate. Then there's the cooling down. Cooling down is essential to any exercise routine to help your body reach normality slowly. After a long run, if you just quit then your body could go into shock. The cooling down sessions decreases your body temperature, heart rate, and respiration. Basically, it returns your body back to normal. The warm-up and the cool-down are the most important part of any exercise session. They help the body prepare and recover from your exercise. Also, the warm up and the cool down make you exercise more efficient. It makes your time worth while. In other words, make sure you warm up and cool down the right way.