Hamstring Stretching: How Much Is Too Much?

(This article was originally written by me for Austin Fit Magazine www.AustinFitMagazine.com)

Recently I had a conversation with a patient who was worried that she couldn’t bend over and touch her toes. She asked if she should be concerned and how could she improve her hamstring flexibility so that she would be able to reach her toes like she could when she was younger. She was worried that having tight hamstrings was contributing to some of her neck, back, and knee issues, and was causing her to have pain after most of her workouts.

This is a question I get at least on a weekly basis. And it’s an important question because going about stretching your hamstrings the wrong way can be a great source of instability through your pelvis and hips. There is, in my opinion, much misconception and misinformation about hamstring flexibility and flexibility in general. There is an optimal amount of flexibility for every joint based on functional and postural demands. We need our soft tissues to be mobile and responsive enough to allow us to move. But we also need them to be structurally sound to provide stability, which goes hand in hand with having the proper amount of strength and responsiveness to keep our bones in the right place at precisely the right time.

It is clearly a problem if you’re too tight and one or more joints can’t move enough to allow you to perform the simple movements you need for activities of daily living and for the more complex set of movements required for athletic endeavors or movement art. As a physical therapist, this is usually fairly easy to treat using whatever form of mobilization, exercise, or self-mobilization that I have in my toolbox. It may take some time to restore normal range of motion, but short and stiff tissues usually respond well to treatment applied with enough force and finesse.

More difficult is the situation where tissues are too long (Figure 1). Yes, it is possible to overstretch muscles and other soft tissues. With overly aggressive stretching the contractile elements of muscle fibers can be damaged along with the other connective tissues that envelop and surround the muscles. This can render the muscle long, weak, and chronically irritated (signaling to the chronic stretcher’s brain to “stretch more!” because that’s what they’re patterned to do when something feels tight and irritated). If addressed early in life (by stopping the over-stretching), muscle tissue can repair itself. But the later in life that one maintains a rigorous stretching program and long, excessively stretched soft tissues, the less likely they will ever rebound to normal range of motion.

Now back to my patient’s question.  Should she worry about her inability to touch her toes?  The answer is “maybe,” since it depends on how she bends over and whether or not there is proper amount of movement through the hamstrings, hips, and spine combined. Besides the hamstring’s function of bending the knee and extending the hip, the hamstrings act on posture to check or slow down the forward tilting of the pelvis. If the hamstrings are too long and not strong enough, it is likely that we will see the pelvis tilting too far forward resulting in a deep lumbar curve.  Habitually being stuck in this lumbopelvic position leads to a cascade of postural alterations.

A forwardly tilted pelvis is associated with lengthened abdominals and tight hip flexors.  This situation is one in which your abdominals are at a mechanical disadvantage for acting as the important “core” stabilizers that we all know they should be. With loss of abdominal tone the belly will protrude and the front lower ribs will flare, deepening the lumbar curve even more. Most people who have this deep lumbar curve develop, over time, hyperactive and short low back muscles (paraspinals, latissimus dorsi, quadratus lumborum) so that when they bend over their lower back cannot completely come out of a deep curve and they can’t fully round (or flex). This perpetuates the hamstring situation. Every time they bend they will utilize their excessive hamstring length and not appropriately round their back. This simply becomes how they move.  Sitting and standing forward bends in yoga are easy to do by pivoting through the hips and not rounding the back at all.  Dead lifts are performed with too arched of a back. Runners may over-stride and overextend their backs.

Whether an individual has tight hamstrings can only definitively be determined through a series of objective tests.  But a quick screen can give one a pretty good idea of their situation.  First, lying on your back see how far one leg at a time can be brought up and towards your head (with your knee straight).  I’ve found that on average men can get to around 80 degrees and women get closer to 90 degrees (Figure 2).  But keep in mind that if your pelvis is already tilted too far forward you may get a false impression that your hamstrings are short because they’ve been placed on stretch before you even start the test.  Finally, a good way to decide if your pelvis is in a good position is to look for a decent amount of rounding through your lower back when you reach to touch your toes. My golden rule is that you can touch your toes with normal lumbar flexion (Figure 3). If you can lay your palms on the floor (like many ex-dancers, gymnasts, and cheerleaders can) it is very likely you’re pivoting too much at the hips through excessively flexible hamstrings.

The main point is that when you feel your hamstrings are tight they may actually be too long and are just irritated. In this case, if you continue stretching you will actually be worsening the health of these tissue. You really may need to be strengthening them so that they can act as efficient pelvic stabilizers. Find a physical therapist to do a more in-depth assessment of your situation so you don’t risk making matters worse.