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August 15, 2012
Why You Don’t Need Flexible Hamstrings
It is one of the most common tests, touch your toes, or even better, reach forward as far as you can. The goal is to measure flexibility, particularly at the hamstrings. After all, it is one of the most commonly strained muscles, accounting for around 12% of injuries in athletes. Yet, no study has proven that hamstring flexibility will reduce injury rate. In fact, some individuals might even increase the likelihood of injury by improving this range of motion.

The Anatomy

First, some definitions. The hamstrings are the three posterior thigh muscles (semitendinosus, semimembranosus and biceps femoris). Flexibility refers to the absolute range of motion in a joint, or series of joints, as well as the length of muscles that cross the joints. The hamstrings are also connected to the back muscles and calves, running from the neck to the big toes. This connection occurs through a thin layer of soft tissue called fascia to make a connection known as the superficial back line. In fact, we have seen phenomenal hamstring improvements by targeting the feet (plantar fascia) alone!   The problem with many tests, like the ones mentioned above, is that any hamstring inflexibility is usually compensated for by range of motion in the lumbar spine, the lower back. So if you can touch your toes, it is hard to truly decipher how much you round your back to achieve this range of motion. This compensation is critical because the lower back serves as a stabilizer, and should not be a major contributor towards flexibility (see Sparta Point).

Flexibility is Global!

So the body is not isolated by muscles. If you are tight in your hamstring you’ll be tight in other muscles. And if you’re flexible in your hamstrings, guess what? Our force plate research has solidified these findings particular in the “hinge” movement signature (see Sparta Point). This signature has extremely high EXPLODE compared to LOAD and DRIVE, an example of this graph is shown to the left. This athlete does not load through the ankle, but rather bends forward at the hips and trunk to produce movement. The result are tight calves to stabilize, tighter hamstrings from over reliance on these extensors. Basically, they are tight and stiff everywhere; making them very explosive but also inflexible to decelerate over a longer period of DRIVE.

How to Fix Inflexibility?

One of the best movements eliminates the explosiveness of “hinge” athletes and stresses a longer range of motion, the Overhead Squat (see Sparta Point). You have to take the hamstrings through a full range of motion, while simultaneously stabilizing your lumbar spine, the lower back that needs to be strong and stiff. In addition to overhead squat, all movements should be taken through a full range of motion to provide the simultaneous benefit of flexibility and strength (stability).


  • Be wary of hamstring flexibility tests, they usually include compensation from the lumbar spine
  • Flexibility is a global attribute, never isolated to one or two muscle groups
  • The stronger, more explosive movement signatures (“hinge”), require more flexibility
You can also just keep targeting hamstring flexibility, isolating muscles will at least ensure that you will never be finished improving.  
August 15, 2012
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10 thoughts on “Why You Don’t Need Flexible Hamstrings”

  1. “making them very explosive but also inflexible to decelerate over a longer period of TIME.”

    I can’t picture what this means. Would you mind giving an example movement and how this athlete’s poorer deceleration would be expressed? I would have thought someone who was explosive was also good at decelerating. Or maybe how being inflexible makes you decelerate over a longer period of time? I would have thought the reverse.

    “One of the best movements eliminates the explosiveness of “hinge” athletes”

    I thought athletes almost always want to be more explosive? I must be confused about what you mean.

    I believe I’m one of these “hinge athletes”. I have super tight hamstrings. (When I did the Presidential Council on Physical Fitness testing as a kid, sit-and-reach was the only test I failed.) I can standing dunk a basketball at 5′ 11″. I never stretch because I’ve felt the stiffness made me more explosive. However, you seem to be suggesting I’m missing out on something. What’s an example of a movement I’d perform better at if I were more flexible?

    Another thought. My sit-and-reach flexibility is terrible. But I used to do CrossFit and the trainers thought I was very flexible because I could easily do full (ass to the grass) Olympic style squats. Since you are advocating overhead squats, I’m guessing flexibility through this ROM is the only thing I really need.

    1. Poor deceleration generally means an athlete cannot smoothly reduce their speed to change direction. A more inflexible athlete like a basketball player is forced to land abruptly because there is reduced ankle range of motion to absorb the impact.

      Explosiveness is not the goal, athleticism and injury reduction are.

      Your conclusion is correct, overhead squat is a great exercise to improve/maintain mobility. If you can or could perform this easily, you are not inflexible or a “hinge”. These athletes cannot and will never perform this range of motion without huge effort

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