Great Stretching Exercises
Regular stretching may also help reduce injuries. Runners frequently develop tightness in the posterior muscle groups. This includes the hamstrings and the calf muscles. The quadriceps and anterior shin muscles may become relatively weak, due to muscular imbalance. The abdominal muscles also tend to be weak on runners who do not exercise them.
The calf (Achilles) should be gently stretched and so should the hamstrings. The best stretch for the calf muscles is the "wall stretch". I recommend stretching one set of leg muscles at a time. One leg is back, knee straight, the other leg is forward with the knee bent. The leg that is back is being stretched. Ten repetitions holding for 10 seconds each is ideal. There are several different stretches to choose from for the hamstrings: Forward bends with the knees slightly bent, knee to chest or leaning forward with the leg out straight in front of you all work. It is important to not aggravate your back while performing hamstring stretches. The FAQ on Stretching is a good source of information about a variety of aspects of stretching.