Stretching
What about stretching? The primary reason for stretching is to increase range of motion at the joints. It does this by provoking a response that lengthens the muscles. However, when we run, we want a certain amount of stiffness in the muscle-tendon units - this gives us a greater potential energy source. Our range of motion needs to be adequate for the exercise we’re going to do but we don’t want too much flexibility. Some studies show that stretching before a workout hampers performance and others do not - the jury is out.
If you do have range of motion limitations, then gentle stretching may be beneficial. This should be done at the end of the workout for a couple of minutes when the muscles are warm. Hold the stretch for 30-60 seconds. Never force the stretch. Here are some stretches to try.