You should start with a warm-up followed by stretching. Warming-up the body before exercise is like warming up your car before a drive on a cold day. It prepares the total machine and its various parts for vigorous activity. Like the car engine, at higher temperatures the body can move more quickly and efficiently. Physical and chemical changes proceed at a higher rate.
Oxygen moves from the blood to the tissues more rapidly.
And nerve messages travel faster. Usually a five minutes warm-up is adequate. Brisk walking, slow jogging, or calisthenics will generally do the job. Stretching, on the other hand, increases the range of motion of the joints. Think of the muscle as a dry sponge.