The hamstrings are tendons that attach the long muscles behind the thighs to the back of the knees. Technically, the word "hamstrings" refers to these tendons, with "hamstring muscles" meaning the actual muscles. However, most people refer to the muscles as the hamstrings. Hamstring stretches are exercises that stretch the long group of hamstring muscles, increasing flexibility and preventing injury.
There are many different ways to stretch your hamstrings. One of the easiest hamstring stretches involves lying on your back with your hands supporting the area behind your knee. To complete the stretch, you straighten your knee gradually until you can feel a stretching sensation in the back of your thigh. Stretch as far as you can, aiming the bottom of your foot towards the ceiling. Do one leg at a time, holding the position for about 10 to 20 seconds.
You can also do hamstring stretches with your rear resting against the corner of a wall or doorjamb. Lie on the floor, and keep one leg positioned there. Put your other foot against the wall and move your leg, straightening your knee until your legs form a right angle with each other. Hold this stretching position for about 10 to 20 seconds.
You can even do hamstring stretches in a chair. To do them, sit in a chair and straighten one leg in front of you. Keep the heel of this leg on the floor. Holding your back straight, move your navel towards your thigh; don't lean the trunk of your body forward as you do this, however. Hold this position for about 10 to 20 seconds, and then switch legs.
Some hamstring stretches can be done while you sit on the floor. To do them, sit with both of your legs extended straight out in front of you. Use your arms to reach forward. Then, bend at your waist to stretch your hamstrings, keeping your knees straight for the entire time. Stay in this position for about 10 to 20 seconds, and then repeat the stretch again.
You don't always have to do hamstring stretches while you're sitting or lying down; you can stand up and do them as well. To do standing hamstring stretches, stand about 12 inches away from a wall. Put your hands on the wall, shoulder width apart, and make sure they are at the same height as your shoulders. Push into the wall while stepping back with one of your legs. Now, hold your back straight as you push the heels of both of your feet into the floor, remaining in this position for about 10 to 20 seconds before you relax and repeat it.