The Hamstring muscle group is located on the back of the thigh. These muscles are responsible for extension of the hip and flexion of the knee. They are very strong and especially important for walking, running, bending and climbing stairs.
In order to stretch your hamstring you will want to find a surface that is between 2-7 inches off the ground. The stiffer your hamstrings, the lower the surface you will use. Next, lift one leg and rest your heel on this surface. Stand erect with a little arch in your lower back and your knees straight. You may already feel a stretch in the back of your thigh. If so, just hold this position. If no stretch yet, then lean forward slightly from your hip joints. But keep your spine in a neutral position. This will allow you to isolate your Hamstring muscles and ensure that the hamstrings are the only muscles being stretched.
Many times people can feel a hamstring stretch in positions when they are also stretching their back. This can be problematic because it becomes impossible to tell when the flexibility in your hamstring ends and the flexibility in your back begins. To avoid this problem try to stay away from the following stretching positions:
Again, keeping your spine in a neutral position is key!