Monday, June 22, 2020

Neuroplasticity and ACLR Rehabilitation: Part III

Last week, we discussed in detail the Grooms study which showed that there are in fact some changes that occur in the higher centers in the brain after an ACL injury.  As much as we think our typical rehabilitation will address this, the reality is and the studies show, these deficits remain unless they are specifically addressed.  These remaining deficits may be one additional factor that leads to increased reinjury rates post ACLR. 

When talking about neuroplasticity and how do we effectively train to improve these deficits that occur, you will hear some talk about the constrained-action hypothesis.  This hypothesis suggests that an internal attentional focus could be negative on an athlete, causing them to interfere with their body's natural movements.  In other words, there are two types of focus, internal focus and external focus. 

  • Internal focus is where there is a focus on body movements.  Typical instructions we give that drive this type of focus is - don't let your knees go in toward midline, don't let your knee go over your toes, etc.
  • External focus is where there is a focus on the movement effect.  Typical instructions we give that drive this type of training is - when you jump, try to touch the hanging ball, when you jump, try to jump past the line.
Benjaminse et al Knee Surg Sports Traumatol Artho 2011 showed that explicit strategies require an internal focus on the movement itself and is less likely to transfer to the sport itself.  However, Implicit strategies require external focus on the movement effect and are more likely to transfer over to sport.  At this point, you may be saying to yourself, well that is great but what the heck does that mean?  Benjaminse et al Phys Ther Sport 2015 performed a systematic review demonstrating the effect of internal focus and external focus instructions on jump landing technique.  What the authors found was that external focused instruction resulted in better motor performance and movement technique than internal focused instruction.  

Based on all this, there are some major takeaways from what we have learned so far.  
  1. Be mindful of the instructions we use when we are instructing athletes
  2. Verbal instructions have a direct effect on motor performance 
I am going to digress here for a moment but we will return to talk about some specific training applications to training.  We have noticed something similar when doing our 3D movement analysis.  When providing instruction to the athlete,for example, on the full squat test, we find the more verbal instruction we give to the athlete the less natural their actual movement is.  
  •  Example 1 - I ask the athlete to perform a squatting motion to 90 degrees with the feet shoulder width apart while keeping their chest up and not allowing their heels to come off the floor.
  • Example 2 - I demonstrate a squat and then ask them to repeat the motion.
In example 1, I will get the motion that I described.  This may not be the natural motion the athlete uses when doing squats but rather their interpretation of what I have described.  In example 2, I will get a squatting motion that is more natural to what the athlete typically does.  In this case, where I am attempting to get a 3D baseline movement assessment, I am want to get their natural motion.  Therefore, I use very little instruction and more demonstration (example 2).

That being said, if you go purely by the research, this would suggest that we don't ever use some form of internal focus training.  Personally, I think there is a place for that.  If you have someone that has a profound dynamic valgus that they demonstrate during all high level functional activity then I am going to work on that.  I will do some targeted training where I will have them control the frontal plane motion of their knee.  I think this is important to build some foundational strength so that when we move to more aggressive sport specific movements that they are able to control that motion.  When I get to that level of training, they then have the base strength and endurance to maintain frontal plane control at which point I will move to some more of an external focus.  

Next week, we will discuss this topic a little more in depth and get into some specific training ideas based on what we are learning.  As always, I appreciate our views and hope you find this useful.  If you do, please follow me on instragram @bjjpt_acl_guy and Twitter @acl_prevention.  I am constantly posting the latest research in injury prevention and sports medicine.  Don't miss out and please share with your colleagues, athletes and training partners and again follow us on instagrm @ bjjpt_acl_guy and twitter @acl_prevention.  Train hard and stay well.  #ViPerformAMI #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 and ACL injury prevention.  He is the founder | developer of the ViPerform AMI,  ViPerform AMI RTPlay, the ACL Play It Safe Program, Run Safe Program and author of a college textbook on this subject.  Trent has performed >5000 athletic movement assessments in the US and abroad.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Vice Chairman of Medical Services for USA Obstacle Racing and movement consultant for numerous colleges and professional teams.  Trent also a Brazilian Jiu Jitsu purple belt and complete BJJ/MMA junkie. 

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