Monday, March 2, 2015

We Don't Know What We Don't Know...But We Know More Than We Think! Part Deux

Last week we talked about research related to identifying all the factors that put athletes at risk for injury.  The thought being not only for use in screening but also to aid us in development of return to sport protocols. 
Research should guide us in what we do.  However, we know more than we think!  We should base what we do on solid research principles and science.  But all too often we get hooked on the fact that we need to have research or a paper to validate everything we do and every thought that we have.  Let’s take several of the previously mentioned studies as an example.  In the previously mentioned Pollard study, one of the conclusions was altered lower extremity coupling (sequence of motor unit firing and muscle recruitment) is a risk factor.  The conclusion was that we need to figure out what leads to this altered movement pattern.  As if this is something that is highly complex when it may actually be pretty simple.
For example, if I do single leg squats on my right leg for 4 months straight and not on my left leg, do you think that there might be some difference in motor unit recruitment and quadriceps strength?  Absolutely and how can there not be.  Now imagine if I did that with every single movement, every single day.  One of the most common problems following ACLR is the fact that the athlete tends to bear more weight on the non-operative leg than the operative.  This is most apparent during a squatting motion and presents itself as a lateral shift of the pelvis to one side during the squatting motion.  In 2013, Atkins et al showed that a lateral displacement of the pelvis during the squatting motion alters the force distribution (and hence strength development) through the lower kinetic chain.   This will not only alter current strength development but also future strength development.  If not corrected, this can persist well beyond the athlete’s return to sport. 
Think this is only present in young athletes or those with less skill?  Think again.  This picture shows an NBA player who demonstrates this motion while being evaluated for return to sport.  Think how this altered motion not only impacts strength, recruitment patterns but also athletic performance.  Fortunately, once identified, it is easy to correct.  Easy?  Yes, easy.  It is not rocket science, just retraining motor patterns and strengthening.  It is a lot easier than you might think but first you have to identify it and start addressing it.  But once identified, if it is not corrected and allowed to continue on into all forms of training (weighted squats for example) then this just simply re-enforces poor movement patterns and alters strength development.
Another example is single limb performance.  We know what the movements are that put people at risk.  We know that if they are present on one limb versus the other that the athlete is at risk.  First, we must assess those in a meaningful way.  Assess them in a way that can guide us to some root cause.  One test alone is not sensitive enough nor provide enough guidance on.  Fortunately, once identified, it is easy to correct.  Easy?  Yes, easy.  Simply put, if we only focus on that movement in the limited amount of time that we have with them in rehab and then what minor change is achieved is offset with poor motor patterns developed with all the other training.  Case in point, this MLS player who has been doing a lot of single limb training.  However, under the guidance of the clinical team he performs great.  But when he works outside that environment doing strength training (lunges, single leg squats, single leg hops) and agility training (cone drills, agility drills) there is no focus or cuing to his movement pattern.  As he is prepared for return to sport and performs the agility test predetermined to validate his ability to return, there is no focus on his mechanics.  The focus is only on can he do it.  If the majority of that training is done with movement like that demonstrated above and his reserve pattern when he is fatigued is to revert to this movement, do you think he is at risk?  What is the simple answer?  Get everyone on the same page. 
Ironically as much as we may think we are, you would be surprised.  I recently had the honor of speaking with a high level professional team and everyone on the performance and clinical side got it.  They knew it and talked about it.  But when put into practical application, what was observed is high risk athletes being trained through agility work with movement patterns which re-enforce movements like those above and continue to put the athlete at risk.  One might argue this might also limit their full athletic potential.
One final example is concussion.  For me, this is a case of why didn't I think of that.  I have the honor and pleasure of collaborating with some really smart people.  People who use our technology to do research and look for correlations that we never knew existed.  One of which is concussions.  We know that concussions impact balance.  In a current ongoing study, we are using the 3D-DMA® with female high school and college soccer players.  During the history of 80+ subjects, you start seeing trends.  One trend that came apparent is those with a previous history of concussions also have poor results on balance tests and tend to have more non-contact orthopedic injuries after their concussion.  But the other correlation is the impact on movement.  Those with previous history of concussion and more non-contact injuries also tend to have horrible control in single limb performance.  This just makes total sense and talk to anyone who has treated these athletes they will agree.  So although I don’t necessarily have a paper to support it, what we do know from the basic science and the research related to concussions, it does make sense that this should be considered a risk factor for non-contact injuries.       
So, although we do not know everything, we do know a lot.  It comes down to putting it into practical application.  Integrate all the factors we know put athletes at risk and drive intervention strategies with the entire team which improves those movements in every training session.  If you like what you see, SHARE THE PASSION!  It is the biggest compliment you can give.  Follow us on Twitter @ACL_prevention and tweet about it.  #Evolve and help us spread the passion and #3DDMA.
Build Athletes to Perform…Build Athletes to Last!™
Trent Nessler, PT, MPT, DPT:  CEO/Founder ACL, LLC | Author | Innovator in Movement Science and Technology.  Dr. Nessler is a physical therapist and CEO/Founder of ACL, LLC.  He is the researcher and developer the Dynamic Movement Assessment™, Fatigue Dynamic Movement Assessment™, 3D-DMA™, author of the textbook Dynamic Movement Assessment: Enhance Performance and Prevent Injury, and associate editor for International Journal of Athletic Therapy & Training. For more information, please see our website at

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