Monday, May 15, 2017

Does Concussion Increase Your Risk For ACL Injury - Part IV

Over the course of the last several weeks, we have been looking at the impact that concussion has on future performance and injury risk.  Based on what we have seen in our work and what the literature shows us, there is a big impact on performance as well as injury risk.  We also know that most of these studies are done on college athletes and professional athletes.  Based on physiology and the research, we know that children's brains are much more sensitive to these changes and therefore the overall impact is much greater than what we see in college and professional athletes.  Therefore prevention of the primary concussion is critical and returning them to sport safer is vital to their future health.

So let's first look at mitigating the risk of concussion.  Can you do that?  In 2014, Collins et al published a paper investigating that very question.  One part of this two part study looked at the impact of neck strength on incident rate of concussion.  This study looked at high school athletes from 51 different high schools across 25 states.  This included 6,704 male and female high school athletes in soccer, basketball and lacrosse.  The authors measured neck strength in flexion, extension and bilateral sidebending. In research terms, a variable that has a p value < .05 has a strong correlation. What the authors concluded was that overall neck strength was a significant predictor of concussion (p = .004).  It was further determined that for every pound increase in neck strength, the odds of concussion decreased by 5%.

What this tells me is that we should be getting some form of base line testing for neck strength for our athletes.  Further, that neck strengthening should not only be included as a part of their strength and conditioning program but that it should also be a key part of their rehabilitation and return to play criteria for returning to sport post concussion.  Previous studies have further indicated that the ability to resist rotational stresses placed on the head will further reduce risk for concussion.  That said, a neck strengthening program should then include strengthening in flexion, extension, bilateral sidebending and bilateral rotation.

 In addition to including neck strength as a part of pre-season physicals and neck strengthening as a part of conditioning and rehabilitation, there are other considerations we should also think about with the concussed athlete.  Based on the previous blogs and the correlation to lower extremity injuries and altered single limb performance, it could be easily suggested that single limb training is an essential part as well of concussion rehab as well as in aiding in return to play.

If an athlete has horrible single limb performance post concussion (as demonstrated here) then we know, from the literature they are going to be at a higher risk of lower extremity injury.  We might also speculate that same athlete is at greater risk for concussion due to the impact on performance and agility.  This would mean the athlete would not able to avoid other players or collisions with other players and hence make them more susceptible to re-injury.  Considering then, the following sequence would aid in progression of the athlete through rehab and return to play post concussion:

  1. Single leg squat - 
    • 10 reps each side
    • Symmetry in frontal plane control and depth of motion
    • No loss of balance - no allowed to touch down contralateral limb throughout the test
  2. Single leg hop - Straight up 
    • 10 reps each side
    • Symmetry in frontal plane control and depth of motion
    • No loss of balance - no allowed to touch down contralateral limb throughout the test
  3. Single leg hop plant - Jump forward, back, lateral and medial  
    • 2 rounds each side
    • Symmetry in frontal plane control and depth of motion
    • No loss of balance - no allowed to touch down contralateral limb throughout the test

This sequence will provide you with a clear indication of their single limb stability and control.  We hope you have enjoyed this series and look forward to our next discussion.  #ResearchThatWorks #ACLPlayItSafe

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >3000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training. 



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