This page deals with some suggested stretches to include when targeting your legs. Maintaining good mobility is a key way of avoiding injuries from running.
Most athletes will include most, if not all, of these in any stretching regime that they are undertaking.
Again, remember - never force an exercise when stretching. Go to the point of tension and hold for 15-30 seconds. For safety, ensure knee and feet alignment and avoid "locking" elbows or knees straight.
Place one leg on a barrier of a comfortable height. Keeping your back straight, gently lean forward from hips, stretching the hamstring. Keep your support leg slightly bent and ensure your supporting foot is facing forward. Repeat on other leg.
This exercise can be done equally well by lying on your back and pulling your leg up towards your chest (effectively replicating this stretch at 90 degrees, but with you leg moving rather than you torso).
Bring one foot to your backside. Clasp with one hand while keeping your knees together and your support leg slightly bent, thus stretching your quadricep or thigh muscles. Keep your back straight and upright whilst ensuring your support foot is facing forward. You can use your free hand on a wall to support yourself.
Lower Leg (Calf) (1)
Step back with one foot and bend your front knee. Ensure both your feet are facing forward, and push your back heel into the floor. Your back should be straight throughout, and you can use a wall for support. Repeat for the other leg.
Lower Leg (Calf) (2)
Take a small step forward with your right foot. Your back should be upright, with your hands on your hips for balance. Bend your knees, placing your weight through your left leg (stretching the lower part of your calf) down into achilles tendon. Keep both your feet flat to the ground and facing forward. Repeat for other leg.
Kneeling, place one foot forward. Make sure your front foot can be seen over the knee. Ease your hips forward and place your hands on your hips for balance.
Sit on the floor with the soles of your feet together as in the diagram. Keeping your back straight, push down on your knees with your elbows to stretch the muscles on the inside of your upper leg, stretching the adductor muscle.