Saturday, February 7, 2009

To wiggle or not to wiggle

or, a conversation with Dr. Tim Hewett; director of the Sports Medicine Biodynamics Center at Cincinnati Children's Hospiatal. Tim has some cool unpublished research going on involving ACL injuries. It goes like this:
Normal & ACL deficient athletes are placed in front of a biofeedback screen, hands folded across chest, SLB, contralateral leg 90/90. A square on the screen moves in different directions, and they have to move their head with the square. The preliminary results look like this:
The uninjured athletes, at lower speeds, performed the task with little variability which increased as the speeds did. This was just the opposite in the injured athletes. They had a tendency to "lock down" the lower extremity as speeds increased.
My question to Dr. Hewett was why this was in opposition to perturbation training concepts, where "stillness" is desirable. His answer was, " in an unstabilized situation locking down is good. In a normally stable position, locking down is probably bad". My response was, "but your bio feedback screen was causing head movement, which created instability, no? His answer was, "humm, that does give me something to think about". I then asked him if perhaps when the instability is driven bottom up, "locking down" is good, and bad when it is driven top down. He said he wasn't ready to come to that conclusion.
Another statement he made was the time from when the foot hits the ground till the ACL lig tears is from 50-70 mlliseconds. Spinal level reflexes occur at 80-150; too slow to prevent an ACL tear. He feels the benefit of neuromuscular training to be preparatory rather than reactive.

5 comments:

Jeff said...

Not surprising comments and content from Dr. Hewitt. They have pioneered the ACL stuff, but it is all lab sterilized. Functionally, they are way down the spectrum from real life.

Not sure what "locking down means". If it means less to no movement, I'm not sure that is good. Slowing down injury biased motion, controlling it so active restraint structures have time to react before pathology, that is the goal of NM training.

I actually agree that ACL programs may not "prevent" injury, especially with outliers, and I've developed several ACL programs myself that are sport specific. But nothing wrong with good, functional NM training to prepare kids. I prefer term ACL Preparation or NM Program.

Last thing, just a gut instinct, but I do not think we are even close to understanding the complexities of the reflexive system. The golgis, pacinians, etc have been studied, but we study what we look for, the body has a gift of complexity beyond our brain power.

Great topic!
Jeff

Joe Przytula said...

Who was that masked man with the "J" on his chest with the cape on?! Thanks for your comments Jeff. In all fairness to Hewitt, by the answers he gave me I think he sees a disconnect also, between what goes on in vitro & in vivo. His comment about the value of neuromuscular training to be preparitory rather than reactive is interesting, and I think fits right in with your last paragraph. The qualities of spatial awareness & athleticism are difficult to define let alone measure. But if we could give that to our patients...

Brian said...

"Reactive" = CKC activities...?
"Preparatory" = OKC activities...?

If the peripheral component of NM control is too slow to react to positions of the lower extremity at ground contact then that changes things.....? Probably not we've known this for awhile..Don't get me wrong I don't think we go back to the ol' days of OKC activities for everything but maybe activities that have transitions of open chain and closed chain components are needed. Most functional tasks have both(walking/running)...Interesting the Hewitt group are big into plyometric activities....I wonder what activities like drop landing/plyos are doing to muscle activity PRIOR to ground contact? I wonder what the difference in the muscle activity and kinematics between injured and controls are before ground contact....? Maybe pertabation at ground contact PREPARES the chain with muscle activity that allows for a better environment to REACT to another ground contact situation....? I believe most of the literature has investigated kinematic/EMG activity at ground contact...Is this a feedback mechanism? "Preparatory" sounds like feedforward mechanisms...? I'm sure these questions have been investigated....
Yuck, motor control concepts back from the classroom...!

Just thinking out loud....

Paul ATC said...

Hello Joe I was at Second Annual Yogi Berra Museum and Learning Center Sports Medicine Workshop and I felt that the techniques that you have your pitchers do are great. I wanted to know if you have that video of the exercises online?
Paul

Joe Przytula said...

Paul- get my email address from the ATSNJ website.