A proper warm-up before vigorous exercise safely prepares the body for the workload. Cold muscles do not absorb shock or impact as well, and are more susceptible to injury.
Warm muscles stretch better and allow greater range of motion for the joints.
Oxygen easily releases from the blood when the muscles are warmed gradually. This prevents getting out of breath early. Warming up also improves coordination, burns fat more easily, and reduces abnormal heart responses brought about by sudden exercise. Perform stretching exercises near the end of the warm-up when the muscles are warm. A warm-up can be just a slow version of the activity.