A warm-up helps your body prepare itself for exercise and reduces the chance of injury. The warm-up should be a combination of rhythmic exercise that begins to raise the heart rate and raise muscle temperature, and static stretching through a full range of motion. The rhythmic exercise may be a slower version of the aerobic activity to come. For example, you might want to walk before you jog, or do some aerobic dance movements before an aerobic class. The stretches in the warm-up should be non-ballistic and cover all of the major muscle groups. Always stretch the lower back before doing any lateral movement of the upper torso such as side bends. It takes your body approximately 3 minutes to realize it needs to pump more blood to your muscles. Warm ups should last approximately 5 – 10 minutes and they should incorporate stretching of large muscle groups (such as the quadriceps, calves, hamstrings, hip flexors, shoulders etc).
After any aerobic activity, the blood is pooled in the extremities, and the heart rate is elevated. The purpose of the cool-down is to bring the heart rate down to near normal and to get the blood circulating freely back to the heart. Stopping abruptly could result in fainting or place undue stress on the heart. The cool-down should also include stretching to help relax the muscles that worked so hard during the activity. It takes your body approximately 3 minutes to realize it does not need to pump all the additional blood to your muscles. A safe cool down period is at least 3 minutes, preferably 4-5 minutes. All cool downs should be followed by stretching of the muscles to avoid soreness and tightness.
These good sense measures, will allow you to enjoy your work out to the fullest and enjoy the benefits of a successful work out. Each has its own purpose, both related to performance as well as injury prevention and safety.