Monday, December 10, 2018

Improving Movement When It Matters - Part I

Over the course of the last month we have been discussing LSI and what it means.  Although it provides us good information, how do we use this knowledge to create exercises that aid in improving LSI.  The idea is not only to provide the strength and endurance that is needed but also to develop the motor patterns in the higher centers that are needed to and which will aid in having maximal carry over to sport.  If we do that, does that really create movement patterns that will carry over to sport?  This is the golden nugget that everyone is looking for.

Throughout this series we are going to dive into some of the philosophy, physiology, neurology and research behind why we do what we do.  During the course of this series we are going to discuss:

  • Kinesiophobia - what is it and how does this limit return to sport
  • Your impact on psychological movement
  • Why Single limb training aids in maximizing return to sport and athletic performance
  • What is the roll of fatigued state training and why this is important
  • Movement at the hips and how this leads to increased risk and altered performance


Kinesiophobia was first described in the literature in the early 2000s but has recently gotten a resurgence with the publication of some land mark studies.  Kineisiophobia is simply the fear of moving.  In physical therapy, you often see this in patients who have suffered a fall.  They develop a fear of falling and thus a fear of moving because they are afraid of falling.  This results in significant alterations in their gate, moving from piece of furniture to furniture and a shuffling type of gait pattern.  This same fear of movement is also quite prevalent in some athletes following an Anterior Cruciate Ligament Reconstruction.  In the initial phases of rehab they may be fearful of walking with full range of motion (so may end up limiting their terminal knee extension), may be afraid of walking without a brace on or putting weight on their involved leg. 

As we progress through the phases of rehab, this can become more profound and psychologically impactful.  Hartigan et al JOSPT 2013 showed that those with higher levels of Kinesiophobia are not only more likely to have a delayed return to sport but also more likely to reinjure upon their return to sport.  Cozzi et al JSR 2015 showed that those with a higher degree of Kinesiophobia may actually result because of a self perceived level of knee function.  Meaning that the athlete subconsciously knows the function or dysfunction of their knee and sense the risk.  Some studies are now correlating the outcome measures for Kinesiophobia (Tampa Scale of Kinesiophobia) to knee outcome measures (IKDC or Marx Scale) and seeing a strong correlation with.  But, what has yet to be determined is the correlation of Kinesiophobia and movement.  One would suspect that those with significant pathological movement of the knee would have greater kinesiophobia than those who have less.

So what is the treatment for kinesiophobia?  Unfortunately there is not a lot in the literature about how to treat kinesiophobia in the athlete.  There is a fair amount out there about how to treat this in the elderly patient and the low back patient but not in the athlete.  Looking at what literature there is, there is some common themes.
  • Education - educate the athlete about their injury, expected progression of rehabilitation and how importance of restoration of early function
  • Graded exposure to therapy techniques to increase confidence
  • Graded exposure to activity
Although this relates to the elderly patient and low back patient, it also has a lot of application to our athletes.
  • Educate the athlete on their injury, the importance of progression of rehab, importance of incorporating single limb activities early in the rehab process, their role in the rehabilitation process and how this aids in faster/safer return to sport
  • Early introduction to single limb activities.  Myers et al AJSM 2012 showed that single limb testing is one of the best indicators of risk with return to sport.  As such, the earlier single limb training is incorporated into rehabilitation the more confidence the athlete will have in that limbs performance over time
  • Incorporating aggressive single limb training in later phases of rehabilitation.  Kristineslund et al AJSM 2013 showed that single limb performance is a better indicator of how the limb will function in sport.  Considering, this should indicate the importance of pushing more aggressive types of single limb training.  Not only does this help from a strength and endurance perspective but will also improve the athlete's confidence in that limb with sport related activity.

It goes with out saying, this is a criterion based methodology.  All too often I see athletes training (many times under the supervision of a therapist) single limb exercises with dysfunctional or pathological movements.  Remember, the movement that you train is the movement you will get on the field.  If you train bad movement, you can't expect the athlete to have good movement on the field.  So what is meant by criterion based methodology is that the athlete is only progressed once they are able to do the previous level of single limb exercise with proper form.  If they are unable to perform without maintaining good position of the knee and hips, then they should not be progressed up to the next level.

Taking this approach is the first step in building the athlete's confidence in their limb, decreases their kinesiophobia and improves their chances with return to sport.

Next week will continue along a similar line of discussion with talking about your impact on psychological movement.  If you enjoy this blog, please share with your colleagues and follow us on instagram @ bjjpt_acl_guy and twitter at @acl_prevention.  #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, 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 and a competitive athlete in Brazilian Jiu Jitsu for 5 years. 

Monday, December 3, 2018

Limb Symmetry Index - What is it and Is it important - part VI


Over the course of the last month and half, we have spent a lot of time looking at the research as it relates to limb symmetry index.  For those of us dealing with athletes, rehabilitation of athletes and especially those of us who are attempting to make more informed decisions for return to play, LSI is often something we must consider.  Throughout the course of this series and after reviewing numerous research articles, it appears this topic is not as clear cut as we would like. 

However, based on the literature, there are some key take homes that we should consider:


  1. What % LSI should your involved be of your uninvolved in order to be considered not at risk or for making return to play decisions?  Based on what we have seen, this answer is not clear but 90% seems to be consensus from the field as well as what most of the researchers are aiming for.
  2. How should we measure LSI? Based on the literature, there is a very compelling argument to compare the involved limb to the baseline data for the uninvolved limb (measurement taken prior to the injury or prior to surgery on the uninvolved side).  
  3. What test should we be using? Every study we looked at looked used different battery of tests.  However, one thing is clear, single limb closed kinetic chain testing is what we should be looking at.  
  4. Is the use of a battery of tests better? Based on what we have seen, the more tests you add in your battery of tests, the less likely your athlete is to pass. 
  5. Does equal LSI tell us anything about risk?  The studies are pretty clear that 100% of LSI does not equate to risk.  You can have 100% of bad movement and still be symmetrical.
  6. What should we be looking for when assessing?  The studies are clear, control of frontal plane motion (magnitude and speed) in single limb performance.

So despite creating a lot of questions, we did get some guidance on some aspects.  Part of the
challenge with getting answers to LSI is historically, we have relied on open kinetic chain testing.  Use of the biodex or similar device to get hamstring to quadriceps ratios right to left, strength, torque, etc.  It was this kind of information that helps guide us on LSI and whether or not the athlete was ready to return to play.  However, we would all agree that sitting in a machine and performing an activity in an open kinetic chain provides very different information than what is provided in a closed kinetic chain.  As we all know, as soon as the feet come into contact with the ground and we are upright, there is a different level of core activation, lower kinetic chain muscle recruitment and changes in length tension relationships.  In other words, they are more in sport like positions.

With closed kinetic chain testing comes the challenge of how do we quantify control of frontal plane motion?  My interpretation may be different than yours which is different than the next person.  However, with the advent of new technologies, there are now ways to quantify these motions in meaningful ways.  What we know, is that we need to assess control of frontal plane motion and that means control of the magnitude of motion and the speed of motion.  Why both?

This comes down to basic physics.  First, the ACL is about the size of your pinky.  The ACL is ruptured with 21.5 N/M of torque (rotational component).  If you look at the calculation of torque, what you get is Ƭ=𝐼ά – inertia *angular acceleration.  The ACL is also ruptured with 250 kg force.  If you look at the calculation of force, what you get is F = mass * acceleration (Hewitt et al Mayo ACL Consortium 2018 - reference for values not calculations).  In addition, force is determined by both the magnitude of the force vector and the speed of that force vector.  The larger the magnitude the greater the force.  If the magnitude is the same but one occurs at a faster rate, this will generate more force.  Considering these physics, it then makes sense that we should be measuring not only how much frontal plane motion that occurs but also the speed at which it occurs. 

As we have mentioned in previous blogs, we have been capturing this with a wearable sensor or IMU (inertial measurement unit, DorsaVi Inc.).  During the test, the athletes perform series of core tests, squat test and single limb tests for a total of 83 reps and 3 one minute timed tests.  The system captures 2D video at 90 frames per second and the sensors captures 3D motion at 200 frames per second.  Each rep is scored based off those motions.  This is a commercial product that has been released to the market since early 2017 (DorsaVi ViPerform AMI) and has now been used in over 269 athletic settings throughout the US.  With the use of the IMU, we are now collecting over 1000 data points for every assessment that is performed.  As a result number of sites using, it has allowed us to capture movement on over 9000 athletes across the US.  With this large mass of data points collected, it has raised one major question.  What is passing score?  Not sure if we know this answer yet.  Let me explain.

If we were only looking at 16 year old female soccer players, we might have a better idea.  But, when you collect across all athletic populations, from high school to professional your data pool to compare mass numbers of a subset population is hard.  What happens when you compare a 16 year old female soccer player to a college lacrosse player to a professional football player to professional MMA fighter?  Should these athletes move the same?  What I can tell you is that there is a HUGE difference in the way a Division I Soccer Player, a Division II Soccer Player and Division III Soccer player moves.  It is one of the things that separates a division I player from a division III player.  Not only do they have better frontal plane control during single limb activities there is significantly less losses of balance during. 

At the same time, we also know that athletes in the same sport but in different positions move very differently.  For example, if a 330# professional football player lineman falls into 15 degrees of valgus at 180 degrees/sec during a hop plant test he may not be at risk where  220# running back with those same motions and speeds may be.  This makes a lot of sense when you consider the amount of running one player does compared to another.  In addition the running back has more cutting and rapid changes in direction resulting in much greater center of mass displacement during single limb movements than the lineman.

So this might lead us to the question, if you don't know what the passing score is then what does the data mean?  What we are able to do is determine LSI in both magnitude of motion and speed of motion.  We do have some normative data for frontal plane motion and speeds of valgus during a single leg squat, single leg hop and single leg hop plant.  We know if you are significantly out of those ranges that you are at greater risk that it will impact your injury risk and your athletic performance.  We also know that if your valgus speeds exceed 200 degrees per second that this has a high correlation to increased risk for non-contact hamstring strains, knee injuries and ankle injuries.  Most of our teams and users do baseline tests so they can use this information to compare to following injury or post intervention.  So the point of this whole discussion is that we are trying to use what the literature tells us we should be looking at and at the same time, using our real time data to drive how we interpret and use this information. 

Stay tuned next week as we start to look at fatigue and impact this has on SL testing and return to play.  If you enjoy this blog, please share with your colleagues and associates.  You can also follow us on Instagram at bjjpt_acl_guy and on twitter at ACL_prevention.  #ViPerformAMI


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, 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 and a competitive athlete in Brazilian Jiu Jitsu for 5 years. 



Monday, November 26, 2018

Limb Symmetry Index: What is it and Is it important - Part V


Last week, we continued our discussion on limb symmetry index (LSI) by examining the study by Toole et al J Ortho Sport Phy Ther 2017.  This was a great study, but also raised a lot of questions.  Some of the main questions raised were:
  • Does an LSI of 90% on these test tell us anything about the quality of movement
  • What do these measures tell us about biomechanical risk factors
  • Is 90% LSI on these test really 90% or could the athlete be sandbagging the results

First let’s look at biomechanical risk factors.  There are two studies out there that we have talked about previously that guide us on biomechanically what we should be looking at.  The Johnson et al Am J Sports Med 2018 study which looked at risk factors for non-contact ACL injuries.  In this study the authors evaluated video capture of the non-contact ACL injuries of NFL players.  What the authors found was that the athlete’s knee was in a position of dynamic valgus at the point of the injury.  As this picture depicts, this is a combination of foot pronation, tibial external rotation and femoral internal rotation. 

Although this is a great study, is what we see in professional athletes applicable to what we see in our  This is where the Owusu-Akyaw et al Am J Sports Med 2018 study comes into play.  Since video analysis is not available for most non-professional athletes, this study used bone bruises observed on CT scan and by applying biomechanical bone models were able to determine the position of the tibia and femur at the time of the injury.  It was determined from where the bone bruises occurred on the articular surfaces that the knee was in a position of dynamic valgus at the time of the injury.  Based on both of these studies, this would suggest we should assess this dynamic valgus position or rather the athlete’s ability to control both the magnitude of this motion and the speed at which this motion occurs. 
younger athletes and weekend warriors?

Traditionally we have used tests like the single leg hop, single leg hop for distance, cross over hop and triple hop for distance as way of measuring limb symmetry index.  Based on the above studies, are these types of functional tests that we use sufficient to measure the magnitude and speed of frontal plane motion?  To evaluate this a little more closely, we should take a look at Wren et al J Ortho Sports Phys Ther 2018.

The objective of this study was to assess biomechanics and symmetry of adolescent athletes following ACLR during a single leg hop for distance.  The idea was to compare those who limb symmetry within recommended guidelines and assess ability to return to play and success with return to play.

Methods: Forty-six athletes with ACLR who were 5-12 months post-surgery (27 female, 19 males) had anthropometric measures taken and a maximal single leg hop for distance was assessed on each leg.  During the single leg hop for distance, the distance covered for each limb was compared and LSI was calculated.  During the hop for distance test, 3D motion capture data and force plate date was collected.  Athletes were classified as asymmetric where the operative limb hop distance <90% of non-operative limb (n=17) or symmetric (n=29). Lower extremity biomechanics were also compared among operative and contralateral limbs.



Results: Compared to controls, asymmetric patients hopped a shorter distance on their operative limb, while symmetric patients hopped an intermediate distance on both sides. During landing, operative limbs, regardless of hop distance, exhibited lower knee flexion moments compared to controls and the contralateral side with lower knee energy absorption than the contralateral side.

During take-off, both symmetric and asymmetric patients had less hip extension and smaller ankle range of motion on the operative side compared with controls. Asymmetric patients also had lower hip range of motion on the operative, compared with the contralateral, side.

Discussion:  There are some obvious statements in the results that we would expect.  Since hopping for distance, the fact that there is an asymmetry would mean that there is less distance covered on one side versus the other.  That is what makes this asymmetrical.  But what is enlightening about this study is that athletes who demonstrated asymmetry also demonstrated less hip motion and less ankle motion at load and landing.  This is very similar to what we see.  With our motion capture system (DorsaVi) we measure tibial inclination.  This is an indirect measure of knee flexion and dorsiflexion.  When testing athletes for RTPlay following ACLR, we find that those who demonstrate higher levels of kinesiophobia (fear of movement measured via TSK-11) also demonstrate less dorsiflexion and knee flexion.  The hypothesis is the athletes subconsciously know that as they descend to greater distances that they will exhibit less control which provides fear of reinjury.  This lack of dorsiflexion, knee flexion and hip flexion at loading equates to less force production and asymmetry in explosive power (distance covered).  At the same time, less dorsiflexion, knee flexion and hip flexion at landing equates to decreased force attenuation and equates to increase in loads departed to the individual limbs. 

Another finding that was surprising in this study was that some athletes would limit their   Hence, in this particular test, the distance would be the same and the asymmetry that is existent would not be identified.  Now whether this occurs consciously or subconsciously, we don’t know but know this does exist.  This may be an argument for what Wellsandt et al J Ortho Sport Phy Ther 2018 suggested based on the findings in their study.  Based on their results, the authors suggested that LSI should be a measure where the post operative limb measurement should be compared to the pre-operative non-injured limb measurement.  This would prevent any sandbagging at the time of the testing and in addition account for any deconditioning that may occur in the non-injured limb during the rehabilitation process.
performance on the non-operative limb to account for the limitations they would have on the operative side.
Based on everything that we have learned through the course of this blog series, it may make us question, are we truly:
  1. Using the right tests?
  2. Measuring what we think we are?  Are we measuring the biomechanical risk factors that we know put the athlete at risk?
  3. Does limb symmetry tell us as much as we think it does?  Can you have 100% LSI and still be high risk?

These questions are one reason that we have taken the approach that we do.  When we measure LSI with the ViPerform AMI, we capture and measure single limb:
  1. Symmetry of frontal plane motion control.  The ability of the athlete to control the magnitude of motion from varus to valgus during single limb testing.  If the limb is outside the recommended barrier, then there is an impact to the overall score.
  2. Symmetry of frontal plane speed control.  The ability of the athlete to control the speed of valgus on load and land during single limb testing.  If the limb is outside the recommended speeds, then there is an impact to the overall score.
  3. Symmetry of tibial inclination. The depth of dorsiflexion and knee flexion during the course of the single limb tests.  If the limb is outside the recommended barrier, then there is an impact to the overall score.

In addition, since we score every rep based on these factors, we can then get a very sensitive measure of LSI.  This is calculated over the performance of 31 reps and one timed test for each limb.  Therefore, if there is change on as little as one rep, we can see this reflected in the score. 

Stay tuned next week as we continue to dive into this topic of LSI and start looking at the impact of fatigue on RTPlay testing and single limb performance.  If you enjoy this blog, please share with your colleagues and associates.  You can also follow us on Instagram at bjjpt_acl_guy and on twitter at ACL_prevention.  #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, 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 Innovation for Select Medical, is Vice Chairman of Medical Services for USA Obstacle Racing and movement consultant for numerous colleges and professional teams.  Trent is also a competitive athlete and blue belt in Brazilian Jiu Jitsu. 


Monday, November 19, 2018

Limb Symmetry Index: What is it and Is it important - Part IV


Last week we continued our discussion about limb symmetry index (LSI).  Specifically we looked at Melick et al Br J Sports Med 2016.  In this study the authors looked at which battery of tests that test LSI that could be used when determining an athlete’s ability to return to play.  This study brought up a lot of good points and also provided us some insight to what battery of tests we should consider when looking to return to play.  However, one question this may raise is how many tests should we use and when we use a “battery of tests” to determine readiness for return to play, what should be considered passing.  Clinically we all have in our minds what should be considered passing but what does the research tell us?
the

Considering this question, we can look at the Tooleet al J Ortho Sports Phys Ther 2017 study to give us some insight. 

Hypothesis:  The hypothesis for this study is that a higher proportion of young athletes who meet the recommended cutoffs will maintain the same level of sports participation over the year following return to play clearance versus those who do not meet recommended cutoffs.

Methods: At the time of RTPlay, the IKDC (international knee documentation committee subjective knee evaluation form), quadriceps and hamstring limb symmetry index and single leg hop tests (single hop for distance, triple hop for distance, crossover hop for distance, and 6-meter timed hop) were assessed.  Proportions of participants who met individual and combined cutoffs were calculated.  Proportions of participants who continued at the same level of sports participation over the year following return to sport clearance were compared between groups.


 Results: Participants included 115 young athletes (88 female and 27 males).  The proportions meeting the individual cutoffs ranged from 34.5% to 78.3%.  The proportions meeting the cutoffs for all hop tests, all strength tests and all combined measures were 53%, 27.8% and 13.9% respectively.  A higher proportion of participants who met the cutoffs for both strength tests maintained a higher level of sports participation over the year following return to play clearance thank those who did not (81.3% versus 60.2%).

Discussion:  Obviously there are some interesting findings in this study.  The cutoff criteria for all the LSI measures (strength and hop measures) was 90% or 10% deficit.  This is interesting considering what previous research has indicated regarding normative values for LSI.  Rohman et al Am J Sports Med 2015 showed 93% of non-injured normal athletes had an LSI of 85% or better.  So one question this raises is if this 90% cutoff or 10% deficit is too high.  That said, those who met this criteria, 81.3% of them were still participating in sport at the same level one year post return to play.  The results of this current study also showed that only when it came to the individual tests, athletes had a higher pass rate but when evaluating multiple tests that the pass rate was only 13.9%.  One thing to consider with this is that all of the hop tests were done in a specific sequence (single hop for distance, triple hop for distance, crossover hop for distance, and 6-meter timed hop) and one right after the other.  Considering, is this lower pass of meeting the criteria with all these test the result of the athlete being fatigued?  Does fatigue have an impact on movement and results on these tests?  Intuitively, we might think this to be the case, but what does the research tell us. 

Philosophically, I personally struggle with what do these tests really tell us?  Most of these tests are scored visually or by some measure (distance or time).  What do these measures tell us about the biomechanical risk factors?  Does the fact that the athlete jumps the same distance bilaterally tell us that they do this with good biomechanical form?  For example, this athlete may jump equal distance and may do it in the same time bilaterally, but does this tell us she is doing this with good form?  Let’s assume she is at 90% LSI, does this mean that she is at a reduced risk of reinjury with RTPlay?  I think we would all say no.

In addition, are these athletes that pass the tests really passing?  Do athletes figure out what we are attempting to test and sand bag their results?  Meaning, could they limit performance on the non-involved side to make the involved side look better so they get a passing score?  Finally, what does the fact that they have RTPlay really mean?  Are they sitting on the bench or are they “performing” at the same level as previous?  We have touched on this fact in previous blogs.  According to the Maiet al Am J Sport Med 2017, we know NFL players performance is reduced up to 2 years “after” return to play.  So even though they are RTPlay, there is a reduction in all performance measures for up to 2 years and their professional career is reduced by 2 years.

Although this is a great study, I think we raised more questions than we may have actually answered.  So stay tuned next week as we continue to dive into this topic of LSI and try to answer some of these questions.  If you enjoy this blog, please share with your colleagues and associates.  You can also follow us on Instagram at bjjpt_acl_guy and on twitter at ACL_prevention.  #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, 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 Innovation for Select Medical, is Vice Chairman of Medical Services for USA Obstacle Racing and movement consultant for numerous colleges and professional teams.  Trent is also a competitive athlete and blue belt in Brazilian Jiu Jitsu. 


Monday, November 12, 2018

Limb Symmetry Index - What is it and Is it important - part III


Last week, as we continued our discussion on Limb Symmetry Index (LSI), we looked at the Wellsandt et al 2017 study which provided some insight as to how we might assess LSI in Anterior Cruciate Ligament Reconstructed (ACLR) athletes.  Traditionally this was done by comparison of the involved limb to the uninvolved limb at the same time (same time post op ACLR).  However, this study indicates that a more sensitive measure may be comparing the involved side post operatively to the non-involved side pre-operatively.  Measuring in this fashion would prevent any of the degradation that might occur to the uninvolved side as the result of lower level of activity due to surgery on the involved side.  In other words, it would prevent the detraining effects on the uninvolved side from influencing the LSI measure.

For the purposes of this study as well as in most instances, LSI is a common measure used to determine whether an athlete is ready for return to play.  However, there appears to be a lot of inconsistency in what is measured for return to play, specifically following ACLR.  So what types of measures should be used to determine LSI? So Melick et al Br J Sports Med 2016 performed a systematic review of the literature to determine what we should be assessing, according to the literature, when we are looking to return an athlete to play following an ACLR. 


Methods:
The authors of this study did a systematic review of studies published from 1990 to 2015.  Ninety studies were included that addressed 1 of 9 predetermined clinical topics.

1.     Preoperative predictors for postoperative outcomes
2.     Effectiveness of physical therapy
3.     Open and closed kinetic chain quadriceps exercises
4.     Strength and neuromuscular training
5.     Electrostimulation and electromyographic feedback
6.     Cryotherapy
7.     Measures of functional performance
8.     Return to play
9.     Risk for reinjury

Results: Rehabilitation after ACLR should include a prehabilitation phase and 3 criterion based posteroperative phases:

1.     Impairment based
2.     Sport specific training
3.     Return to play

A battery of strength and hop tests, quality of movement and psychological tests should be used to guide progression from one stage to the next.  Post-operative rehabilitation should continue 9-12 months.  To assess readiness to return to play and the risk of reinjury, a test battery including strength tests, hop tests, and measurement of quality should be used.

Discussion: This study brings up a lot of good information but also brings to the forefront some important questions.  First, as a sports physical therapist, the blaring question is around the 9-12 months of rehabilitation.  Although I could not agree more and studies are pretty clear that athletes should not return to play for 12 months, how do we get insurance to pay for this?  With changes in health care and insurance reimbursement, the majority of insurance companies limit your care to 4-5 months post operatively.  None will pay for rehabilitation that includes return to play.  This despite the fact that reinjury rates are so high, osteoarthritis rates are so high and the majority of athletes who have will return to play whether or not they get the appropriate course of care.  Considering, I think we must be more creative in our plan of care and more inclusive of collaborative partners in the entire continuum of care for our athletes.  By early inclusion of our athletic trainers and strength coaches in the process not only allows us to have a more well-rounded approach to the athlete, it is also in the best interest of the athlete’s long term joint health and overall health to have this approach.  At the same time, we must include innovative ways to continue the athlete’s progression without our immediate and constant direction.  Programs like the ACL Play It Safe program provide us structured ways to progress an athlete through the process in addition to what our athletic training and strength coach counterparts would do. 

 Another point this brings up is what tests should we use to return an athlete to play?  When reviewing the literature, there does not appear to be a lot of consistency in how this is assessed.  Some studies look at variance in quadriceps strength, some in single leg hop distance, single leg triple hop distance, LESS test, timed hop, agility drills, the list is endless.  So what is right?  

 Next week, we will start to look at this question in a little more depth.  So make sure to stay tuned.  If you enjoy this blog, please share and follow us on instagram @ bjjpt_acl_guy and on twitter @ ACL_prevention.  #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, 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 is also a competitive athlete in Brazilian Jiu Jitsu. 



Monday, November 5, 2018

Limb Symmetry Index - What is it and Is it important - Part II

Last week we started our discussion about limb symmetry index (LSI) and specifically related to the lower kinetic chain.  We also know this is a measure that is commonly used by physicians and in sports medicine when making return to play decisions.  Based on some of the information provided last week, we have questioned on whether this is truly providing us a measure of risk, especially when looking at return to play.  Last week, we discussed a study by Rohman et al that looked at changes in LSI with ACLR rehabilitation but then also discussed the Adams et al study which showed that 93% of normal uninjured athletes LSI index was below or at the standard currently being used to determine return to play. 

This week, we will look at another study by Wellsandt et al J Ortho Sports Phys Ther 2017 which dives into this subject a little deeper.  The objective of this particular study was to evaluate LSI in return to sport testing and its relation to reinjury rates after ACLR.

Methods: Seventy athletes completed quadriceps strength and 4 single leg hop tests before ACLR and 6 months after ACLR.  LSI for each test compared to the involved limb measures at 6 months to uninvolved measures at 6 months.  Estimated preinjury capacity (EPIC) levels for each test compared the involved limb measures at 6 months to uninvolved limb measures before ACLR.  Reinjury rates were tracked for a minimum of 2 years post ACLR.

Results: Forty (57%) of patients achieved 90% LSI for quadriceps strength and on all hop tests.  20 patients (28.6%) met 90% EPIC levels for quadriceps strength and all hop tests.  Twenty four patients (34%) who achieved 90% LSI for all measures at 6 months after ACLR did not achieve 90% EPIC levels.  11 patients (27%) sustained a 2nd ACL injury at 78 weeks (median time).  8 of the 11 patients (73%) with the 2nd ACL injury passed with 90% LSI at 6 months.  But 6 of these 8 (75%) did not achieve 90% EPIC levels.  EPIC levels was superior at predicting 2nd ACL injury.

Despite previous studies stating there is little to no degradation of the noninvolved limb post ACLR, EPIC levels might indicate the contrary.  In this study, the most sensitive measure appears to be comparing the involved limb post ACLR numbers to pre-operative uninvolved numbers.  From a rehabilitation standpoint, if we can get pre-operative numbers, it would make sense to use EPIC levels when trying to determine return to play. 

That being said, it also leads us to the question, wouldn't it be even better if we had baseline movement data to compare to.  What if we had pre-participation movement data taken in physicals, would this be even more sensitive data to compare to.  For those of us that treat athletes who have had an ACLR, we know right after the injury the athlete is definitely going to be hesitant with movement.  Especially with hopping types of motions for the fear of landing on the involved injured limb.  So, would it be better to compare this to movement where there is not that hesitation at all?

All that said, are these LSI measures (whether done in traditional LSI measurement calculation or EPIC calculations) really providing information about "movement quality".  If the athlete had horrible movement prior to surgery on both legs, are we truly measuring risk?  When looking at the athlete depicted here, if this is the preoperative test on the uninvolved side, does his LSI or even his EPIC levels truly depict his risk for reinjury?  Are we missing something here or are we not using enough measures to measure this correctly?

Next week, we will look at some of the common battery of tests used for testing LSI and what they are telling us.  So make sure to stay tuned.  If you enjoy this blog, please share and follow us on instagram @ bjjpt_acl_guy and on twitter @ ACL_prevention.  #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, 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 is also a competitive athlete in Brazilian Jiu Jitsu. 

Monday, October 29, 2018

Limb Symmetry Index - What is it and Is It Important

Over the course of the last 5-10 years, there has been a lot of discussion in the literature about limb symmetry index or LSI.  So, what is LSI and what does it mean?  LSI or limb symmetry index is simply the variance between one limb (typically the involved or injured limb) and the other (uninvolved) limb.  This is usually represented as a % of the involved to the uninvolved (LSI = score involved/score uninvolved x 100).  LSI can be used to describe the variance between upper extremities or lower extremities.  However, most of the research done in this area is in relation to the lower extremity.  LSI is often used by physicians as one of the factors that is considered when determining an athletes ability to return to play. 

When looking at LSI for return to play, most physicians will tend to default to the conservative and shoot for an LSI of 90% to 95%.  The thought process here is that if there is greater than a 5-10% variance then this will put the athlete at greater risk.  Limb symmetry IS very important but, is this an accurate assumption?  And whether it is or not, how are we measuring LSI and is this truly an accurate measure of risk?  Let's first look at what does the research tell us about normative values for LSI.

In a study by Rohman et al Am J Sports Med 2015, the authors did a retrospective case series looking at LSI. 

Methods: Retrospective case series of 122 patients who underwent ACL reconstruction and rehabilitation.  Each subject received standard functional testing at 4 and 6 months post operatively.  The standard functional test (SFT) consisted of 12 exercises performed in the following order:

  • Single leg anterolateral reach - Patient balances upright on the tested leg only, and reaches with the contralateral hand as far as possible along the floor, at a 45 degree angle anterolaterally. (I.e., standing on the right leg, the patient reaches with the left hand forward and to their right). The patient is not allowed to bear weight on the reaching arm.
  • Single leg anteromedial reach -  Patient balances upright on the tested leg only, and reaches with the contralateral hand as far as possible along the floor, at a 45 degree angle anteromedially. (I.e., standing on the right leg, the patient reaches with the left hand forward and to their left). The patient is not allowed to bear weight on the reaching arm
  • Stork stance with eyes open - Patient stands on the tested leg with arms crossed over chest, and must maintain their balance without using arms for balance or touching down with the opposite leg. The trial ends at 60 seconds unless the patient loses balance sooner.
  • Stork stance with eyes closed - If patient is able to complete 60 seconds with eyes open, the test is repeated with eyes closed.
  • Retro step up - The patient steps backwards with the tested leg onto a raised platform, and straightens to an upright position without pushing off with the front (untested) leg. The patient then must then reverse this motion, performing a controlled descent bringing the untested leg back down to the floor. This is repeated with platforms of increasing size until the patient cannot complete the step up. 3 trials allowed at each height.
  • Single leg squat - Patient is standing on the tested leg without any support, and squats as deep as possible. Arms can be extended for balance. The opposite leg is not allowed to touch the floor or brace against the tested leg.
  • Single leg hop - Patient begins standing on the tested leg only, and hops forward as far as possible. Patient must demonstrate a balanced and controlled landing, without touching the untested leg to the ground for support.
  • Single leg triple hop - Patient starts balanced on the tested leg, and takes 3 consecutive hops forward on the tested leg only. Patient must demonstrate balanced and controlled landings, without touching the untested leg to the ground for support.
  • Cross over triple hop - Patient starts standing on the tested leg only. The patient then takes 3 consecutive hops forward parallel to a line of tape placed on the floor. Each hop must land only on the tested leg, and must land on alternating sides of the line of tape. Patient must demonstrate balanced and controlled landings, without touching the untested leg to the ground for support.
  • Timed hop - The patient starts balanced on the tested leg, and hops forward on that leg only as quickly as possible, over a distance of 6 meters. Patient must demonstrate balanced and controlled landings, without touching the untested leg to the ground for support.
  • Core plank - Patient is positioned prone on their elbows and toes, with a neutral spine. They must then hold this position for 60 seconds. The test ends if patient gives up, or displays excessive arching/sagging through the lumbar spine.
  • Single leg bridge - Patient is positioned supine with knees bent. They then straighten and elevate the untested leg, and with the tested leg extend through the hip, pushing down and lifting their core off of the ground until the hips are neutral. The patient is not allowed to touch the ground with the untested leg or brace against the tested leg.
The SFTs were performed at 4 and 6 months post operatively for both the involved and uninvolved leg.  Ten of the twelve SFTs were analyzed and compared for changes in LSI and absolute function in each limb.  

Results: In all patients with multiple SFTs, the involved limb performance increased in all tests with the exception of the stork stance with eyes closed.  Univolved limb performance increased in 5 SFTs and decreased in none.  5 tests showed initial LSI below 90% (single leg squat, retro-step up, single leg hop, cross over triple hop and timed hop.   

Conclusion:  During ACLR rehabilitation, the improvements seen in LSI indicated absolute increases and were not attributed to univolved limb deterioration.  The single leg squat, retro step up, single leg hop, crossover triple hop and timed hop are suggested as highly useful tests since showed initial LSI below 90% and had significant improvement with rehabilitation.  


So this study shows us that there are some good measures of LSI, but are they really telling us you are at risk and are we being too stringent on the thresholds?  Meaning is this 90%-95% LSI too restrictive and more importantly, does 95% or 100% LSI mean you are not at risk? 

In a study by Adams et al J Ortho Sports Phys Ther 2012 the authors showed that 93% of normal individuals (those without injury) had an LSI of 85% or greater.  So I ask again, is the current threshold of 90-95% too restrictive and if you don't meet that threshold, are you really at risk?

As we have seen over and over again, you can have 100% LSI of really bad movement.  I think we could all look at this athlete and despite having 100% LSI, we would agree she is at risk.  So, are we relying too much on LSI and what is it really telling us?  We will continue to dive into this question again next week. 




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, 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 is also a competitive athlete in Brazilian Jiu Jitsu.