Begin each training session with a moderate 5-10 minute warm up walk. Not necessarily in the walking form we discussed in the technique and form article on this site, just fast enough to let the muscles know they’re getting ready to work. At a convenient location, stop and stretch any areas feeling tight. By taking the time to warm up and stretch, you will perform better and reduce the chances of injury.
It is even more important to develop a cool down routine. Walk the last half mile of each workout at a very moderate pace and finish by stretching the entire body. This is when your muscles will be warm and flexible.