Monday, April 28, 2014

In The Non-Contact ACL Issue That Complex? - Part II

Over the course of the last 15 years, there has been a plethora of research related to ACL injuries.  Over this time, it has resulted in some very specific and common findings consistent among multiple studies and various institutions.  These include:

·        Adduction in the frontal plane is bad!  That is demonstrated here in an NFL player doing vertical jump test.  You can clearly see his knees going in.  This is directly correlated to adduction moment which puts a lot of stress on the ACL.  If you don’t assess adduction in the frontal plane, how can you possibly know risk and address?  Case in point, this particular athlete had a movement assessment and scored a 17 (minimal risk).  It does not take a PhD to see this player is clearly at risk.  So are we truly assessing risk if we are not measuring this?


·        Single limb testing is a better predictor of mechanics during sports participation than bilateral performance.  Running and the majority of sports is single limb in nature, so makes sense that testing single limb is a better representation of than bilateral.  Asymmetry in one’s ability to control their limb in single limb performance is not only an indicator of risk but also potential performance issues.  That is demonstrated here with a US Olympic athlete during a single leg squat.  You can clearly see her adducting past the medial aspect of the foot which increases the adduction moment.


·        Core & hip strength play a vital role in stability of the limb during single leg motions.  Lack of stability at the hip and core result in the femur moving into an adducted position under loads.  Higher the load, the higher the adduction.  That is demonstrated here with our high school dancer.  She has a tremendous amount of hip/core weakness which results in complete instability of the lower limb during single limb activity.  With higher load activities, these mechanics would increase in their magnitude and result in increased risk of injury and performance issues.


·        A lateral shift during the squatting motion alters limb loading and force production.  Altering the loading of the limb results in more wear and tear on one side versus the other and alters strength production on one side versus the other.  That is demonstrated here with the high school football player doing squats.  This motion done without loading (as in training) significantly alters the loading through the limbs, alters the quad/hamstring development and significantly impacts injury risk and performance.

·        Fatigue impacts movement.  Sports is physical in nature!  If the test we use is not physical in nature we will NOT see where the deficits are.  We don’t want to look at how they look at going on the field, we want to see how they look during the 2nd half when injuries are more likely to occur and when performance issues impact team performance.  That is demonstrated here with this Olympic athlete who looks great in short isolated movements but once fatigue sets in he starts to fall apart.  Working him at a higher level you see where his system falls apart, where his risk is and where his performance can improve.  As an Olympic athlete, he scored a 15 on the movement assessment used by team yet he has a tremendous difficulty stabilizing in single limb.

First and foremost, you have to assess motion!  You have no way of knowing if you are improving motion if you do not assess and “quantify” movement.  No matter how hard you train, what functional exercises you do, if you don’t quantify movement you will never know if you are improving movement.  Quantifying movement is the ultimate in accountability measures.  If you think your training changes movement, prove it by comparing pre/post intervention.  If your interventions change movement, you will see it reflected in the test.  BUT, the way you measure movement has to be reflective of movement represented in the research and in sport.  We know what movements have an impact on injury risk and performance.  We know the one’s proven to have a direct impact!  Those are the ones we must assess.  To not assess and quantify does a disservice to both the athlete and the organization.  When you assess movement, it must take into consideration the factors above.  Movement assessment needs to:
1.      Quantify adduction in the frontal plane
2.      Quantify single limb performance
3.      Quantify and compare single limb performance to the contralateral side
4.      Quantify lateral shift of the pelvis during the squatting motion
5.      Be physically challenging!
Is there a way to simplify it all?  Yes!  In the coming months there will be the release of an advanced 3D technology that will be available in rehab centers, pre-participation physicals, fitness and performance centers and retail centers that accurately assesses and quantifies movement.  A technology that uses the latest movement capture systems to automate and quantify all the above and which will provide you with the solution (what is the root cause of the movement and how do you change with training).  
Movement is complex but the solution to movement dysfunction is not.  There is an answer and it is on the horizon!  Protect future joint health, protect future performance and protect future scholarship and life opportunities. 

Build Athletes to Perform…Build Athletes to Last!™

About the author: Trent Nessler, PT, DPT, MPT is CEO of A.C.L., LLC and is a practicing physical therapist with 15 years in sports medicine and orthopedics. He has masters in physical therapy and doctorate with focus in biomechanics and motor learning. He is the founder/developer of the Dynamic Movement Assessment™, Fatigue Dynamic Movement Assessment™ and author of a textbook “Dynamic Movement Assessment™: Prevent Injury and Enhance Performance”. Trent is also associate editor of the International Journal of Athletic Therapy and Training and Member of the USA Cheer Safety Council.  For more information, please see our website at

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