The above video is of me showing a trick on how to increase hamstring flexibility instantly.  Why you would need to do this, I’m not sure.  The only time I’ve ever seen a purpose for it is when my sister had to do the V-sit and reach for the President’s Physical Fitness test.  Other than that, it’s just kind of a fun trick to do to people.

Contest time!:
Let’s see if anyone can come up with a reason why the trick works.  Throw guesses out there, it doesn’t matter if it’s way off.  Eventually, I’ll post the reasoning of why I think it works.
 Whoever comes up with ‘correct’ or  plausible or interesting answers, I’ll send all of them a couple good powerpoints by experts in the field that I have that aren’t online anywhere.  That means, give it a go, use your brain, and I’ll send e-mail you some powerpoints.

 One is a very interesting look at Thyroid function and athletic performance, including blood work from world class athletes.  Another is a presentation on Strength training for endurance athletes (runners, cyclists focused) that does a great job of summarizing all the research.  So Guess Away!


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    1. April on January 22, 2010 at 6:35 pm

      I'm guessing that it has something to do with reciprocal inhibition – the contraction of the quadriceps causing the hamstrings to relax somewhat therefore increasing flexibility in the hamstrings when you go to forward bend the second time.


    2. JS on January 22, 2010 at 9:36 pm

      It tilts the pelvis?

    3. Drs. Cynthia and David on January 22, 2010 at 11:12 pm

      I think April's got it right. It's like the trick with your arms in a doorway- push hard against the frame then step out and your arms go floating up. After the sustained contraction of the quads, the opposing muscles (hamstrings) have diminished tone and so can stretch more.

      Anyway, would love to read the info you mentioned.



    4. Anonymous on January 23, 2010 at 3:17 am

      I have no idea! 🙂

    5. Coach Mike on January 23, 2010 at 1:50 pm

      April is right. When you press on the tendon above the quad it causes an immediate responce that makes the quad tighten and both the glutes and hamstrings relax allowing for you to go lower in your stretch. This will increase your flexability of both the glutes and hamstrings if it is repeated enough times over a long period of time. The bennifits to this increased flexability to a distance runner can be three fold. 1. less injuries, 2. shortened time to loosening up (especially early in the morning) 3. increased raw speed and power (longer tendion more elasticity). The last could be the greatest bennifit to a racer. It will not bring about a big time drop but it can be the difference in who gets to the finish line first in a close race. To me a lot of Allen Webbs recent success is closely related to paying attention to these types of training aspects when he puts scuh a strong emphasis on his base fitness and power training.

    6. Eric on January 23, 2010 at 10:27 pm

      I disagree with Coach Mike, the doctors and April. In the bent knee position one can apply force downward with the arms without causing a contraction of the quads. The hamstring loosening still happens, even if the rectus femoris fails to contract. However, to apply pressure with the arms one must activate the core. To stabilize your upper body as you press down with your arms, you contract your pelvic floor muscles, tva and iliopsoas, reducing anterior pelvic tilt. Reduction in anterior pelvic tilt causes loss of hamstring tone, increases flexibility on toe touch stretch.

    7. Peter (duerrp *at* on January 25, 2010 at 6:01 pm

      Hmm, difficult one, I guess Eric is right about the quads not contracting in that position. But could it be some kind of neural thing that is activated when you exert pressure on the fascia?

      My answer is probably way off, but I Would love to get some of the powerpoint stuff 🙂

    8. Anonymous on January 25, 2010 at 8:22 pm

      I tried pressing on a bench instead of above the knees. same result, so I guess pressure on the fascia doesn't matter.

    9. PC on January 26, 2010 at 7:54 am

      Some part of the increased stretch is "suggestive". If the initial limit is reached and "marked", and a follow-up stretch is done with the "expectation" that the second stretch could be further (i.e after reading the all the info and video) – an increase of about 3 inches can be achieved easily (tried and tested). But I admit it does not explain why one can stretch another inch or so after bending the knees – so there must be an additional feedback caused by the contracted quads – some antagonistic response maybe? Is there a real answer?

    10. stevemagness on January 26, 2010 at 12:49 pm

      Thanks for the great responses! I've got a smart readership.

      I'm afraid there's no exact answer. It's most likely a combination of the things mentioned above. When I learned this several years ago from a Biomechanics professor his thoughts were it was mainly due to reciprocal inhibition via pressing above the knee triggering proprioceptors.

      But, everyone has brought up some interesting points, so I don't think it's as simple as that. Obviously some is suggestive, but it works even without suggestion. There are probably several mechanisms at play.

      Anyways, for those who commented e-mail me if you haven't already supplied your email and I'll send out the powerpoints. Great discussion! (email is

    11. Allan on January 30, 2010 at 12:40 am

      Same reason active isolated stretching works? You're flexing the quads and activating the hip flexors in front which causes the opposing muscle groups (hamstrings and glutes) to relax.

    12. Mark E. on November 25, 2011 at 5:36 pm

      Its to help recover like whartons stuff?

    13. Anonymous on March 5, 2012 at 5:16 pm

      you are releasing the tension in your back?

    14. Anonymous on March 18, 2012 at 4:06 pm

      Due to prior running injuries I've seen doctors very well versed in bio-mechanics. I've had issues with pelvic tilt, and, upon inspection, many teammates on my track meet have the same pelvic tilt causing tightness of the lower back on one side and hamstring tightness on the opposite side. In most track runners (sprinters included) this appears to be present with an anterior tilt on the right side and posterior on the left. The anterior tilt is associated with hamstring tightness and pain due to the pelvic bowl pulling upon the hamstring, making them feel relatively short. The posterior side pulls upon the back, accounting for back tightness. This is especially prevalent in the hurdlers I've met. Over time, if not corrected, the individual could have muscles short on both sides, making this more difficult to correct. This seems to work on the same problem-

      There are four ways I've seen this corrected, two of them possible to perform with no outside help. The first is to lay down facing up, bring the knee on the anterior side up bent to 90 degrees, place a hand on that knee and resist with both hand and leg for 5 or so seconds and repeat several times. That corrects the anterior side and the posterior side is corrected by pulling the knee to the shoulder on the same side then resisting to make the stretch isometric for about 5 seconds, stop resisting but continue the stretch and it should shift closer, then repeat.

      Another involves two people with both legs held up at about 90 degrees with knees bent. The other person, my doctor in this case, places an arm so that it is on the anterior side superior to the knee for the leg with anterior pelvic tilt, and the posterior side superior to the knee on the other side. The person on the ground then attempts to "crush" the other person's arm while they resist. This is done for a few seconds at maximum controllable effort and repeated until the pelvic tilt is leveled.

      The third way I actually came up with and my doctor approved. It is to do the same as above, only substituting a stick or rod of some sort for the other person's arm and doing this without another person's help.

      The fourth, performed with help, has the person laying down. They then bend the knee (I think on the side of posterior tilt, thought I don't recall exactly), while the helper places the knee against the helper's chest just below the armpit while holding the lower part of the leg horizontal (parallel to an imaginary line across the hips, shoulders, etc). An isometric stretch is then performed the same way as done in the first method where the helper pushes in, the person being treated resists then releases multiple times, and the leg should be pushed farther towards the person's chest each time.

    15. banglacow on January 18, 2013 at 9:02 am

      issit because the quads are stressed and compressed and cause the hamstring to stretch more?

    16. Xander Lawson on January 31, 2013 at 2:51 am

      With a little effort and time, this is actually relatively simple. All it takes is regular exercise, proper warmups, and some trips to the chiropractor.

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