We all know we have tight hamstrings. They're a big problem, a bigger problem than you probably realize. Not only do tight hamstrings limit knee motion, but they also limit hip motion and place excessive stress on the low back. Also, because of the sciatic nerve running with them, they can pinch this nerve and cause problems all the way down into the ankle and foot.
Most people realize that they need to stretch their hamstrings, but often what happens is that the hamstrings refuse to relax. I know many people who have spent an entire year stretching their hamstrings only to have them be just as tight, if not tighter, by the end of the year. This is because of two major problems with hamstring stretching: we stretch too vigorously, forgetting that the point is to relax them, not to literally stretch them longer, and we use stretches that are by nature not useful for relaxing the hamstrings.
Let me explain this with some examples. The most common hamstring stretch is the toe touch. Whether you do this in sitting or standing, notice what happens when you reach for your toes. You're loading your hamstrings when you do this. It's as if you're handing your hamstrings the entire weight of your upper body and then saying, “okay, relax.” This is an unreasonable request. The hamstrings won't relax under such circumstances.
Another option is the straight leg raise. Here you lie down, hold your thigh perpendicular to the ground, and then straighten your knee. This is a much better option than the toe touch, but it is active work and doesn't exactly encourage relaxation. Another alternative is the doorway stretch, using the doorway to hold your leg in the air. This is more like it! Now you can actually lie there and relax as you stretch. But people still don't make much progress with this stretch. This is because the knee needs to be totally straight to really get the hamstring, the calf muscle that intertwines the hamstring behind the knee, the sciatic nerve, and the surrounding fascia to all relax. Unless you're already very flexible, you won't be able to get your knee totally straight with the doorway stretch unless you're so far from the doorway that you actually have to engage your hamstrings to hold your leg in place. Once again we meet the problem of the stretch itself not being conducive to relaxation.
For all these reasons I suggest the Leaning Hamstring Stretch. This is a modified toe touch that actually encourages relaxation. You bend forward and lean your upper body into a sturdy object. The sturdy object takes away the weight of the upper body, removing the load on the hamstrings, allowing us to nicely stretch the hamstrings with little to no risk to the low back. You keep your knees completely straight the entire time, ensuring that the hamstrings, calves, sciatic nerve, and the surrounding fascia are all stretched together.
Thirty seconds a day with this stretch can work wonders for the hamstrings. Make sure your knees are straight and that you only bend far enough to get a mild stretch. The stretch should relax within 10 to 30 seconds, meaning that you should no longer feel a stretch in that position. That's the feeling of the hamstrings relaxing. You're becoming more flexible.