The Evolving Knowledge of Movement - Part II - What We Know Now

Last week, we began our discussion talking about what we are learning from collecting over 1000 data points associated with movement on over 14,000 athletes across the US.  This week, we continue this discuss on what we are learning regarding movement.  It is this "actionable" data that we can then improve our interventions to provide our athletes with better injury prevention programs, rehabilitation programs and performance enhancement programs. 

• Variance in Multisport vs. Single Sport - when comparing athletes who play or specialize in one sport vs. athletes who play multiple sports, we see that multisport athletes have less frontal plane motion, speeds are lower and there is less frequent loss of balance.  Considering this and the fact that the less frontal plane control you have the greater risk of injury, it is one more reason that we should push our athletes to be multisport athletes.  In a recent study using the ViPerform AMI on single sport athletes and multisport athletes, the authors found there was much greater control of frontal plane motion in multisport athletes.  These findings will be presented in Science Meets Practice at the 2020 APTA's Combined Sections Meeting in Denver, Colorado.
• Variance by position - when comparing athletes at the same level of sport (Division I) and in the same sport (football), we find that control in single limb performance changes based on position.  For example, we see that running backs have much better control than lineman.  
• Speed Matters - when comparing comparing those that can control frontal plane motion to those who can not, we see some trends associated with speeds and injury risk.  We also see a speed barrier (once this speed is exceeded) that is associated with chronic lower extremity injuries.  Athletes that exceed this barrier are those that have chronic whole kinetic chain issues (ankle, knee, hamstring, etc).  
  
• Direction of Movement Impacts Speed - the movement we see associated with the highest magnitude of valgus and speed of valgus is the medial hop.  This is a very challenging movement for most athletes to stabilize but is also a critical movement to control.  
• Concussion Impacts Frontal Plane Stability - when comparing like athletes (same gender, level of sport and sport) we see that those that have had a previous concussion have a slight decrease in frontal plane stability (amount of motion and speed of motion) but a significant increase in recorded losses of balance during testing and less control at the pelvis during testing.
• Frontal Plane Stability Impacts Performance - when comparing the magnitude of motion and the speed at which valgus occurs to flight time, what we see is that as frontal plane stability decreases there is a decrease in flight time (amount of time in the air with single leg hop).  Flight time is an indication of power output in single limb performance.  These results would suggest that there is a significant loss of kinetic energy which translates to a decrease in power output and hence decrease in flight time. 
• Time to Stability - time to stability is the time that it takes for an athlete to stabilize once they perform a hop.  Typically this is seen once they land and they have multiple smaller hops to gain their balance or stability.  The time for the first contact on the landing to the time where they stop hopping is defined as the time to stability.  We are able to capture the time stamp from the moment they land to the time where they become stable.  One of the things we see is that the longer it takes to become stable, the greater the increased risk for injury.  
• Pelvic Motion Matters - during single limb testing, all too often we are focused on what is occurring at the knee and forget about the rest of the kinetic chain.  One thing we see is that some athletes may be able to control their knee motion but are not able to control their pelvic motion.  Just like the knee, we see that athletes who have greater degrees and speed of pelvic motion during single limb testing are at greater risk for injury and specifically at greater risk for low back and hip injuries.  

I hope as you read this you can see all of the implications not only to injury but also to performance.  That now that we know about these factors we could look for ways to improve.  That is exactly what we have done.  Next week, we will continue that discussion on how we change these movements through movement guided interventions.  Stay tuned as I am super excited to share with you.  If you enjoy this blog, please share with your colleagues, athletes and training partners and please be sure to 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 has also been training in Brazilian Jiu Jitsu for 5 years and complete BJJ junkie.