Static stretching consists of holding a position and slowly allowing the muscle to elongate or stretch.
Dynamic stretching involves motion. Kicks, squats, jumps, etc. are used to warm up and engage the muscles through movement.
Before a Run
Before starting your run, you should warm up your muscles with some dynamic stretches. The goal of the dynamic stretching is to prepare your muscles for the effort of the workout by increasing circulation, heart rate and range of motion.
After your dynamic stretching routine, you can begin the warm up phase of your run. Typically, you’ll want to run a couple of minutes slower per mile than your target pace until you start to break a sweat. Ten minutes should do it. However, colder weather requires a longer warm up period.
Tip from the Pros: Try foam rolling before a run if you have sore muscles
After a Run
After your run, you should allow your body to cool down by jogging slowly or walking around for 5 -10 minutes. This promotes quick recovery and allows your body to clear out waste products from your muscles.
Many runners swear by a routine of static stretches after each workout to prevent injury and muscle soreness. Others view static stretching as ineffective and possibly dangerous.
“If you can run comfortably, and without injury, there is no need to stretch,” says William O. Roberts, professor in the Department of Family Medicine and Community Health at the University of Minnesota Medical School. –RunnersWorld
But, runners and coaches seem to agree that if static stretching is part of your routine, after the run is better than before.