Monday, June 1, 2020

Efficient Movement Drives Performance & Mitigates Risk - Part VI

Last week, we started our discussion about quadriceps weakness and how this can influence movement and a patient's perception on their functional ability.  This was specific to those who have had an ACL reconstruction.  However, that being said, I think there is a lot we can learn from this and which we can apply to any athlete.  It gives us some guidance on some things we can assess (isometric quadriceps strength and single leg squat/hop) as well as some thing we can do in our training to help reduce these deficits, improve performance and mitigate injury risk.

However, I think one question that comes out of this discussion is why does this persist after an ACL reconstruction if they are doing rehab and what can we do to change it.  Why does it persist?  I think there are a lot of complexity to this question.

One aspect is that there are neuroplastic changes that occur in the brain following an injury.  There has been an increasing body of evidence that is showing that there are changes that occur in the higher centers (brain) after an lower limb injury.  Studies are showing that some of the neuroplastic changes that are occurring remain after rehabilitation and after the athlete has been returned to play.  It is speculated that some of these neurological changes that occur could be one reason for the higher reinjury rates after an athlete returns to play.  If we could identify where these changes are, then this might guide us on what type of training we could do which would improve and reduce reinjury rates.

Grooms et al J Orthop Sports Phys Ther 2017 looked at 15 ACL reconstructed athletes who were cleared to return to sport and compared them to 15 matched controls.  Each participant filled out an IKDC (which we talked about last week) and had a functional MRI.  A functional MRI is an MRI that is done while the athlete is performing a task (pictured above).  In this study, the task was performing knee extension while having an MRI. 

What this study showed was that the athletes who had poor scores on the IKDC (their perceived functional ability of their knee) did in fact have diminished activity in the ipsilateral motor cortex and ipsilateral cerebellum.  What does that mean?  Essentially, this means that these athletes had altered activation in areas of their brains which is responsible for sensory, motor and sensory-visual-spacial processing.  We are going to dive into this subject a lot more on the next blog series but this information clearly guides us on types of exercises we can add to our rehab and our performance training that is going to improve input in these areas resulting in improved performance and mitigating risk of injury.

I touch on this here, because this may be one reason that we see some of the things we do in rehab.  For the athlete that has massive lateral shift (shifting weight to one side during squatting), this may be from these higher center neuroplastic changes.  In addition, the changes in the primary motor cortex could be one additional reason that the quadriceps have difficulty firing and why an asymmetry in quadriceps develop continues even at the point of return to sport.  So, how can we change this and can we use exercises to increase input to these higher centers?

Sadly, I think it is not as complex as we make it. Applying some simple concepts early on in the rehab process will aid in elevating a lot of this.  Some examples:

  1. Correct a lateral shift ASAP.  The first time you start any type of squats, partial, sit to stand or whatever it is, correct the lateral shift.  Do not let this persist.  Training this motion and allowing this lateral shift starts creating these movement patterns as the default movement pattern in the higher centers.  This means this will be the movement they resort to when they sit, get down to the commode, sit in a car, on their bed ect.  This will then be the movement pattern they will carry over to functional squatting, training activities and sport.  WE must correct it and correct it right away.   
  2. Start working recruitment of the quadriceps right away.  If they can't do the motion concentrically, start them doing it eccentrically.  Muscles are stronger eccentrically and I have often found we can use this to start recruiting muscles the athlete is having a difficult time recruiting.  Try this technique.  Take an athlete that can't do a long arc quad set or a straight leg.  Raise their leg for them up to the end range of motion then have them hold it.  Do this for a couple of reps then have them slowly lower it.  Do that for 5 reps then have them do it immediately concentrically after completing an eccentric contraction.  They can do it!  Why?  We have reengaged that synaptic pathway and got it firing again.  
  3. Add BFR to your routine.  Blood flow restriction training is a great tool we can use to recruit more of the muscle.  By using BFR, you create a blockage of the venous return which causes a buildup of blood within the muscle (buildup of blood in the muscle resulting in back flow preventing more oxygenated blood from entering).  As result, muscle gets super pumped up and creates a hypoxic state.  This is due to less oxygenated blood coming in all while the task or load continues to be performed.  This decrease in O2 causes a fatigue and an increase in motor unit recruitment and more whole muscle activation.  This is how we get more of the muscle involved and greater recruitment of the whole muscle versus partial and hence more hypertrophy.  
  4. BFR alone not enough - add electrical stimulation.  We know that electrical stim (ES) can aid in recruiting more motor units within the muscle when done with low level exercise (leg raises, short arc quads, long arc quads).  You can increase the impact of both the ES and the BFR by combining the two. 
  5. Single limb performance - single leg activities are absolutely an essential part of your rehab
    program and early.  Obviously we want to stick within the guidance of the protocol, but the sooner you can start single limb exercises and single leg squats while controlling the frontal plane motion of the knee the less likely you are to have an issue with quadriceps weakness and risk of reinjury.  To promote desired motor patterns we are looking for, it is imperative that the athlete controls frontal plane motion, hip motion and motion at the foot an ankle.  Full kinetic chain stability is the key.  
All these techniques aid in increasing motor unit recruitment, more of the whole muscle contraction and aid in developing desired motor patterns in the higher centers.  This is just the beginning.   Keeping in mind, there are more ways to do this and in our next series, we will talk about specific training techniques we can deploy to create neuroplastic changes and help mitigate risk for reinjury.   What I will say, is if you add these techniques to your rehab process, quadriceps atrophy and weakness will not be an issue. 

That concludes this series.  Next week, we start to dive into some of the research related to the changes that occur in the higher brain centers and what specific strategies we can do to help retrain..  Stay tuned as I am super excited to share with you.  Have you followed my instragram @bjjpt_acl_guy lately?  If not, you are missing out.  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 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 also a Brazilian Jiu Jitsu purple belt and complete BJJ/MMA junkie. 


Monday, May 25, 2020

Efficient Movement Drives Performance & Mitigates Risk - Part V

Last week, we discussed rapid neuromuscular response or RNMR and how it is important to include this type of training methodology into our ACL rehab and prevention.  We discussed how, by incorporating this type of training methodology, we can reduce risk of injury, train rapid stability in single limb activity and how this can carry over to sport, especially for those who have indirect contacts in sport.

This week, we will continue this discussion by looking at how quadriceps function impacts both movement and kinesiophobia.  Anyone that has dealt with an ACL reconstructed athlete over they years knows that pushing quadriceps strength is vital, something you start very early and can sometimes be something that is very difficult to get.  This is going to be the area of focus for us this week as we look at a couple of studies that tie quadriceps strength and symmetry to both biomechanical function in single limb performance, injury risk and kinesiophobia.

In a study by Smith et al Am J Sport Med 2015, the authors looked at 75 athletes following ACLR who were cleared for return to sport (RTSport).  Each athlete filled out an IKDC (international knee documentation committee form), performed a biodex test for quadriceps strength and had their lower extremity biomechanics measured during a single legged hopping task.  What the study showed was that patients who demonstrated the greatest quadriceps deficit at the time of testing also scored poorly on the IKDC and demonstrated movement asymmetries and decreased functional performance on hop testing. 

For those not familiar with, the IKDC is a patient reported outcome that is the patient's self reported or patient's perceived  function of their knee during a series of functional activities.  The IKDC asks a series of questions related to pain, function, ect and is the patient's perspective of their functional status of their knee during performance of these tasks.  Poor performance on this test has been shown in the research to be highly correlated to the actual functional status of the patient's knee.  The results of this study would suggest that a decrease in quadriceps strength post ACLR would be associated with a decrease in functional ability in daily activities as well as sporting activities.

This study also evaluated lower kinetic chain biomechanics during performance of single leg hopping tasks.  The results showed a strong correlation (P value <.05) between quadriceps weakness and altered lower kinetic chain biomechanics during single leg hopping.  These biomechanical differences noted with quadriceps weakness are also associated with an increased risk for non-contact lower kinetic chain injuries.

This can give us some guidance, not only from an assessments standpoint but also from a treatment standpoint.  Obviously lower chain kinematics are altered when the athlete experiences quadriceps weakness, so one could assume that assessing single limb movements (like a single leg squat) would be one way we could functionally identify this and could use this further as a training method. 

Knowing that poor quadriceps control and decreased function following ACLR is something we often see in sports medicine and rehabilitation, this led Ho et al J Physio 2015 to investigate this.  In this study the authors tested 100 athletes post ACL reconstruction who were cleared for RTSport and wanted to see the correlation between quadriceps function, kinesiophobia and quadriceps strength.
This study showed a weak correlation to strength and kinesiophobia but a strong correlation to strength and altered biomechanics during single limb exercises.  In looking at this study, it is difficult to really determine the full depth of the methods and how they were carried out.  However, the results are somewhat similar to what Wilk et al J Ortho Sport Phy Ther 1994 showed in this much earlier study.  It this study, the authors showed a correlation to quad strength, results on an IKDC and performance of single limb testing.  So if quadriceps strength was poor, both IKDC went down as well as symmetry in performance in the single limb testing.  However, one thing to keep in mind, for the single limb testing performed in the Wilk study, there was not a measure of biomechanics during performance of the task but rather simply the ability to perform the task.  As we know and as pictured above, you can be symmetrical and still be at risk.

Before we close out this discussion on quadriceps strength, one thing that often comes up is how do you test that.  I don't have a $30K or $60K Biodex machine in my clinic to test.  Is manual muscle testing alone good enough.  Before I answer that, I would refer back to several earlier studies by Wilk et al and Ellenbecker et al Isokin Exer Sci 1996.  In the Ellenbecker study, they compared isokinetic testing to standard manual muscle testing.  What the study showed is that there is sometimes up to a 28% strength deficit or variance in right to left strength before a "experienced" clinician can pick that up in traditional MMT.  So how can we possible test and be reliable? 

With the advent of technology, there are numerous products on the market to help.  Hand held computerized dynamoters have come down dramatically in price and you can now get them for under $1000.  This is a great alternative to the expensive isokinetic machines and will aid in giving more reliable data.  Now all of this was great information to have but the question should be, what do I do with it. 

Next week we will begin to discuss why these deficits continue to remain through rehab and how we can address.  Stay tuned as I am super excited to share with you.  Have you followed my instragram @bjjpt_acl_guy lately?  If not, you are missing out.  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 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 also a Brazilian Jiu Jitsu purple belt and complete BJJ/MMA junkie. 


Monday, May 18, 2020

Efficient Movement Drives Performance & Mitigates Risk - Part IV

Last week, we introduced the concept of indirect contact ACL injuries and how these occur.  Although this may be new knowledge for some, this concept has been out there and well published for the last 4 to 5 years.  Considering, this adds another spectrum to the mechanism of ACL injuries, contact, indirect contact and non-contact.  We know that we can impact non-contact injuries but can we influence indirect contact?  Absolutely. 

Last week, we began to discuss the concept of rapid neuromuscular response or RNMR.  This is a form of training where we train the athlete to have a rapid response to an external stimulus which results in whole kinetic chain stability.  We typically use perturbation training with this and in our last blog we discussed some simple concepts to keep in mind with perturbation training.  With this type of training, we start with some simplistic movements and go to more complex ballistic types of movements.  As an example, I will go through a series of single leg exercises from simple to much more complex.  The goal of this series is that the athlete is training for stability in single limb performance.  When I say that, I want them to control both the magnitude of frontal plane motion and speed at which that motion occurs.  

Last week, we also talked briefly on perturbations and what those are.  We also stressed the importance of making sure we are training the types of movement patterns we want (stability).  Considering, our stress should not exceed the athlete's ability to provide stability to the stimulus.  However, before we move on, we must also discuss the concept of both anticipated and unanticipated perturbations.  As far as a progression goes, I will start with anticipated (where the athlete knows this stimulus is coming) to more difficult unanticipated (where athlete does not know what rep the perturbation may occur on).   This series we will discuss just an example of a progression keeping in mind there are a lot of ways in which we can alter this and change it up.  


We will go through a series of single leg exercises.  Before we do, I would like to highlight some of the things we see when we look at our movement data.  

Hip position - athletes have a very hard time maintaining proper hip position during the course of single leg exercises.  As mentioned in the beginning of this blog series, there are some common hip patterns we see where the athlete loses control of the pelvis during single leg tasks.  Keeping that in mind, if we do not correct this during single leg training, then this will be a pattern they continue and will carry this over in sports.  

Control frontal plane motion - we have talked a lot about this but this is especially critical in our training.  Our goal is to aid them in controlling the speed at which this motion occurs.  Are they still going to fall into a dynamic valgus position?  Most likely yes.  But, when they do, we want them to control the speed at which they fall into that position.  Therefore, as a part of our training, we must work on them controlling this motion.  If they loose the ability to control this motion, simply step back the exercise.  What I mean by this, is if they are doing a single leg squat (where the contralateral limb is off the ground) and unable to control the frontal plane motion, then step them back to a split squat where the contralateral limb is in contact with the ground.  This is a more stable position (easier) and they can still work on the neuromuscular control to control this position.  This is better than simply stopping the exercise as is or continuing it.  Continuing the exercises reinforces the negative movement patterns and stopping does not help build the level of endurance they need to control.

Considering the above, the following is a sequence we will use for RNMR.

Single Leg Lunge RNMR Series.  This is an exercise we all use a lot and are familiar with.  However, in this example
we will start with the athlete performing a set number of reps and then provide perturbation at a given range. (20 - 45 - 90 degrees knee flexion).  

Once technique is mastered, this is progressed to performing the single leg lunge with the spiral technique.  The spiral technique uses the theraband CLX band wrapped around the stance leg in a very specific manner.  For specifics on this technique, please refer to the following video.  The end of the clx is held by the clinician and can be used to provide perturbations (pulling the band in a medial and diagonal fashion - resulting in an adduction and internal rotation force).  This would start with performing this through concentric phases then concentric and eccentric phases.  

Once technique is mastered, then this is progressed to include (without the band) upper and lower body perturbations.  From there we move to performing with split squats, to single leg hops.  Once technique is mastered, then this would progress from anticipated (knowing this will happen on every rep) to unanticipated. 

Obviously there are 1000s of variations that can be performed with this sequence.  You can add doing landing to take off in sprinting.  Or running to do a jump with indirect contact, to change in direction (much later phases of rehab).  Key is to make sure we are training the movement pattern we want (control of frontal plane motion of the knee and transverse, sagittal and frontal plane motion of the pelvis).  

This is just one example but should give you an idea of how we are using perturbation training to aid in creating these rapid neuromuscular responses to control movement.  Next week, we will take a dive into how deficits in quadriceps strength can add to kinesiophobia and changes in frontal plane biomechanics.  Stay tuned as I am super excited to share with you.  Have you followed my instragram @bjjpt_acl_guy lately?  If not, you are missing out.  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 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 also a Brazilian Jiu Jitsu purple belt and complete BJJ/MMA junkie. 


Monday, May 11, 2020

Efficient Movement Drives Performance & Mitigates Risk - Part III

Last week, we reviewed a recent study by Markstom et al Am J Sports Med 2020 which looked at ACLR athletes and compared them to controls on several hoping types of tasks.  This lead to a discussion about medial hops, some of the things we see with this as well as this concept of knee robustness (ability to tolerate perturbation during functional activities and still maintain joint configuration).

This is a concept that makes a lot of sense to me and I was first introduced to this ~6 years ago.  A lot of this initial work comes out of Australia and is a deep dive into the mechanism for non-contact ACL injuries.  We know from the research that ACL injuries occur from non-contact (where there is no contact with an individual or object resulting in the ACL injury) and a contact injury (where there is contact with something or someone that results in the ACL injury).  An example of the non-contact ACL injury is when a player has a rapid change in direction and their knee goes into a dynamic valgus and they rupture the ACL.  An example of the contact ACL is a another player strikes the knee of an opponent and this ruptures the opponents ACL.  We also know from the literature that the majority of injuries are non-contact in orientation (70-80%) and these are the ones we can impact the most with screening and injury prevention techniques.

However, there is also another category of ACL injuries called indirect contact.  This is where there was contact with the athlete prior to landing and their change of direction.  As an example, a soccer player goes up to head a ball (pictured).  The player in the red jumps for the ball.  In the higher centers in his brain, there is a motor plan that his brain resorts to for effective execution of that motion.  For this to work efficiently, his body is in a certain position and he lands with his legs and center of mass in a predictable position.  However, what happens, as he heads the ball is that the player in the blue strikes his shoulders in mid-flight.  This drastically alters where he lands, where his center of mass is relative to his legs and his feet may not be in the optimal position.  When he then changes direction to run after the ball, his body is in the wrong position and he ends up falling into a rapid dynamic valgus and ruptures the ACL.

In a study by Stuelcken et al J Sport Sci 2016  the authors performed a systematic video analysis of 16 anterior cruciate ligament injuries sustained in elite level netball players during televised games.  Of the 16 injuries, 8 of these were identified as indirect contact ACL injuries.  In the indirect contacts a player was jumping in the air to receive or intercept a ball when they received a perturbation in the air.  As a result, the athletes landing was unbalanced resulting in excessive loading to the knee that was ultimately injured.

This concept of indirect contact is new to many but it has been a concept that has been investigated for the last 10 years.  We know that we can create preventative programs to aid in reducing non-contact injuries but is there any form of training that can be done to aid in prevention of indirect contact injuries.  Absolutely!

One concept we talk about a lot with our certification course is the concept of rapid neuromuscular response or RNMR.  With this approach to training, we want to teach to the athlete to have a rapid neuromuscular response to external stimulus (indirect contact).  This response should be one that results in stability and full kinetic chain stability.  In order for this form of training to work, we must first talk about the concept of perturbation training.  This is a technique that we often employ in rehabilitation but which is rarely used in performance training.  Frankly, there is application in both settings if it is done correctly.  

Before we do a deep dive into the training, we must first talk about how perturbations should be done.  When I teach this in our courses, I see a lot of different ways that perturbations are applied.  Keeping in mind, the goal we are looking to achieve is a rapid neuromuscular response to provide stability to the stimulus applied.  So, our stimulus, perturbation, should not be so great that it breaks the athlete resulting in movement.  We are looking for stability.  

An example pictured here.  I have an athlete in a lunge position and hold their arms out in front of them, palms together (pushing palms together to bring in pec contraction) and asked to stabilize their shoulders, core and LKC.  I ask them to not let me move them.  I provide perturbations with my hands to their hands, shoulders and knee.  My perturbation (or force) does not exceed their ability to stabilize.  I want train a motor pattern that results in them stabilizing versus allowing the body to move with the stimulus.  These are two very different motor patterns and for prevention and ability to resist indirect contacts, we have to teach to stabilize when these occur.  This is one area where I see a lot of folks make a mistake.  The force they provide is greater than the athletes ability to stabilize so they are essentially teaching them to break instead of stabilize.  As the athlete improves, we obviously provide more and more force but initially we are looking for the rapid response for stability.  

Next week, we will dig a little deeper into this concept of rapid neuromuscular response and how we can train this from simplistic to ballistic movements.  Stay tuned as I am super excited to share with you.  Have you followed my instragram @bjjpt_acl_guy lately?  If not, you are missing out.  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 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 also a Brazilian Jiu Jitsu purple belt and complete BJJ/MMA junkie. 


Monday, May 4, 2020

Efficient Movement Drives Performance & Mitigates Risk - Part II

Last week, we discussed a recent study by Garner et al Int J Kines Sport Sci 2020 where they used wearable sensor technology (ViPerform AMI) to assess athletes and used that information to implement a corrective program all season long in DI athletes.  We also started the discussion on how capturing mass data like this is allowing us to see trends prior to being published in the research.

We discussed several of the movements we see in the core/hips specifically with single leg testing.  Most of us that have assessed movement for a while see this and the impact this has on the center of mass (COM) displacement during single limb testing.  We are now starting to see this investigated in the research.

Markstom et al Am J Sports Med 2020 recently published a study looking at landing control and whole body movement strategies of those with ACLR during hops and side hop tests.  The purpose of this study was to see if there is a difference between ACLR athletes and controls during functional testing typically performed as a part of a functional return to sport assessment.  Specifically they wanted to see if knee robustness and whole body movement strategies were altered after ACLR. 

Before we get into the study, we first need to understand what does knee robustness mean.  Knee robustness is the ability to tolerate perturbation during functional activities and still maintain joint configuration. 

Methods: An 8 camera Vicon system and 2 synchronized force plates were used to capture and calculate joint angles and moments during side hop landings on 32 ACLR athletes and 32 matched controls.  ACLR athletes were average of 16 months after reconstruction with hamstrings graft. 

Testing procedures included:

  • Patient reported outcome measures – IKDC, KOOS and Lysholm scale
  • KT 1000 arthrometer
  • 3 hop tests
    • One leg hop for distance
    • One leg vertical hop
    • One leg rebound side hop – standing on one leg, athlete hops lateral over a distance 25% of body height and immediately back medially.
  • Isometric knee extension and flexion strength
Results: Knee robustness was lower for the first 10 degrees of motion after the initial contact then successfully stabilized.  ACLR athletes when jumping on the involved leg demonstrated significantly greater motion of the trunk, hip and knee.  There was lower but acceptable hop and strength performances with the exception of knee flexion (hamstring) strength.

Discussion: Keeping in mind this study was done in Sweden, there is a difference when comparing ACLR and rehab done in Sweden versus the US.  Couple of things to keep in mind is that in a socialized medicine environment, surgery is very different.  There is often a long delay in getting an MRI and having surgery.  This can sometimes be as long as 6 months.  In addition, the therapy that is done is also very different.  Neither is wrong but it is different than what happens in the US.  So this is important when comparing outcomes from studies that are done abroad.  That said, one of the things you will see is that the subjects were average 22-14 years of age and all of them had a hamstrings graft.  Most surgeons in the US would do more bone patellar bone grafts than hamstring.  In addition, the ACLR subjects, 85% were back in sports and were all 16 months post op.  

One (of the many) things I liked about this study was the hop testing.  The one leg rebound test is very similar to the hop plant test that we use.  One of the things we find is that the landing on the medial hop is one of the most telling motions.  If you break down the moment where they are hopping back (rebounding) medially, the subject moves their COM medial, explosively pushes off with the leg, attempts to stick the landing and has to stop the COM from continuing medially and control their knee from collapsing into a dynamic valgus.  This is extremely hard to do.  We actually find this to be one of the most telling motions.  Those with larger displacement of their COM and higher speeds of dynamic valgus in this movement, we see are at higher risk of lower kinetic chain non-contact injuries.  

One of the challenges with the way they looked at this motion was they had the subject hold a rope behind their back with both hands.  The challenge with this is that this dramatically changes the mechanics of the motion.  If we think about it, doing this causes the subject to extend their arms back, elevate the chest.  The resulting posture brings the thoracic spine and lumbar spine into an increased amount of extension.  Doing this alters the mechanics of the jump.  You will have less side flexion and sidebending with the lateral and medial hop in addition to some increase in bony stability (due to the extension) of the core.  This is not how hopping occurs and I think you will miss a lot of natural or pathological motion that occurs in the core/hips with this positioning.  

The natural motion is to have the arms forward and the arms behind results in a more upright posture.  That aside this was done with both groups (ACLR and control) and there was notable differences.  That said, I would love to see more studies actually looking at COM displacement during these motions and looking at speeds of dynamic valgus on the medial hop.  There is a correlation there but of course, we can't say that until they prove that in the research.  

Next week, we will look a little more at the concept of knee robustness and what happens when there is a disruption to the COM prior to the landing (shoulder contact with another player when going for a header).  Some interesting things we are seeing in this realm as well.  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 also a Brazilian Jiu Jitsu purple belt and complete BJJ/MMA junkie. 


Monday, April 27, 2020

Efficient Movement Drives Performance & Mitigates Risk

Over the course of this blog, I have attempted to present a lot of research on injury prevention.  Although the majority of this has focused on mitigating risk for anterior cruciate ligament (ACL) injuries, it has also extended to all lower kinetic chain injuries from the foot to the spine.  You have also heard me talk about an athletic movement assessment (ViPerform AMI) I created to assess these risk factors using a 3D wearable sensor (called dorsaVi).  This product was commercially released in 2017 and has now been used to assess over 18,000 athletes across the US. 

Part of the intention of developing this was to provide clinicians, physicians and strength coaches with an efficient and reliable tool to assess biomechanical factors that put an athlete at risk for injury and which negatively impact performance.  When used in pre-season physicals, the hope is that this information could be used to guide seasonal movement training which would improve results on this test.  This is not intended as a sales blog but more what happens when you collect mass movement data utilizing technology.  With over 1,000 data points per assessment, we now have over 18,000,000 variables related to athletic movement.  What this allows us to do is identify trends in athletes that we may not see in the literature for some time. 

First, I would like to give a shout out to a colleague of mine who has been using this system in DI athletics since its first prototype in 2016.  Her team just published their first paper.  Garner et al Int J Kines Sport Sci 2020 used the ViPerform AMI to manage risk of injury in a strength and conditioning program in DI volleyball players. 

Methods:  In this study, the authors performed an assessment on the volleyball players during pre-season physicals.  The results of the test were then used to develop specific exercise program for the athletes that they would perform 3x/wk for the entire volleyball season.  The athletes were tracked all season long and injury rates were compared to EMR (electronic medical record) data for the five previous seasons.  Although this is not the ideal way, when you are working with a team, it is hard to use one group as your experimental group and the other as your control.  Most teams and coaches won’t go for this.  Problem is, if there is a change in other variables season to season (athletic training staff, strength staff, strength programming, replacement of the court, etc) this can have an impact on the injury rates.  This was identified and no other variables were changed season to season with the exception of the assessment and specific assignment to a movement program based on the results.

Results:  Compliance with the program was greater than 90% with performance of the program at the conclusion of practice 3x/wk.  When comparing to the previous 5 years of EMR for non-contact injuries, what the results showed was a 67% reduction in hip injuries, 37% reduction in knee injuries, 50% reduction in lower leg injuries and 67% reduction in thigh injuries.  There were no recorded ACL injuries for the entire season for the first time in 5 years (this was not statistically significant since the recorded ACL injuries for prior years was 1-2 per season).  In addition, as a result of the intervention, there was a >40% reduction in health care spend for the team that year (this includes MD visits, x-rays, MRI, surgery and physical therapy).

Although this is the first paper, there are several studies and papers in development.  But this is meeting our first goal which was to provide clinicians (PTs and ATCs), physicians and strength coaches with tool to identify those at risk and use that information to make meaningful changes to their program to impact.  In addition this this goal, another goal of this system was for it to be a venue by which we could collect mass data as it relates to athletic movement.  Collecting mass movement data (>18M variables on >18K athletes) in this way has never been done before.  By vetting this data, this allows us to identify trends in movement and risk prior to this being identified in research.  The key is not to just identify it but more importantly determine what do you do about it. 

An example is something we see in single limb (SL) testing.  Obviously one of the things we are looking for in SL testing is how stable is your knee in the frontal plane.  Does your knee fall in towards mid-line (or valgus collapse) and does it do that at a high rate of speed?  We know this is a risk factor and is well documented in the research.  It is one of the key factors we measure.  However, there are some athletes that are good at controlling this motion of the knee.  However, when they do, some of them will lose control higher up the kinetic chain at the hip.  We call this a loss of pelvic control and it can be represented in several different ways.

Trendelenburg – in a single leg squatting position, this movement occurs when the hip on the opposite side you are standing on falls.  So, if the athlete is doing a left single leg squat (as depicted here) the right hip will fall.  This is an indication of weakness in the left gluteus medius.  If this muscle has full strength, it would contract and prevent the right hip from falling. 

In addition to the abnormal forces that are created along the entire kinetic chain, it also tends to lend to an increase in loss of balance during single leg activities.  In addition, the dropping of the hip creates a stress on the right left hip joint, left sacroiliac joint and lumbar spine.  This can lead to a plethora of hip and low back problems during athletics.  Aside from injury risk, this also has a huge impact on athletic performance.  There is a negative impact on maximal power production and agility. 

Retro-trendelenburg – in a single leg squatting position, this movement occurs when the athlete shifts their weight over the stance leg.  So, if the athlete is doing a right single leg squat (as depicted here) they shift their weight over the right hip.  This is an indication of weakness in the right gluteus medius on the left side.  The reason this is done, is this position creates stability by placing the femoral head deeper in the socket (acetabulum).  This creates boney stability so the glute does not have to work as hard.  If this muscle has full strength, it would contract and the athlete would remain more upright.

In addition to the abnormal forces that are created along the entire kinetic chain, it also tends to lend to an increase in loss of balance during single leg activities.  In this scenario, when the athlete (depicted here) do single leg hopping activities, you will see her migrate to the right as the center of mass is pulling in that direction.  This puts a lot of stress on the hip joint and lumbar spine facets on the right side.  In addition, this has a negative impact on maximal force production and agility. 

Cork-Screw – one of the most devastating movements we see in the hip is the cork screw. During a single leg squatting, this movement occurs when the athlete’s hip drops and rotates.  If the athlete is doing a right single leg squat (as depicted here) the left hip drops and there is rotation at the right hip.  This is easy to recognize by what the left foot (in this case) is doing.  What you see is the left foot cross mid-line and appears on the opposite side of the right leg.  This indicates moderate to severe weakness of the right gluteus medius as it is failing through its full range of motion.  With dropping of the pelvis and the rotation that occurs at the right hip, this puts a tremendous amount of shear stress on the labrum of the hip and can lead to hip pathology.  This can also lead to problems in the SI joint and low back pain.

In addition to the abnormal forces that are created along the entire kinetic chain, it also tends to lend to an increase in loss of balance during single leg activities.  In this scenario, when the athlete (depicted here) do single leg hopping activities, you will tend to lose his balance a lot and as a corrective strategy, often create a significant amount of rotation at the knee.  Additionally there is a negative impact on maximal force production and agility. 

Keeping in mind, this is a trend we have seen in collecting movement data on 18k+ athletes but has also something we have seen throughout the years of development.  Some might say, well this is not proven because I have not seen that in the literature.  That is, until now.

Next week, we will start looking at a series of studies that further confirm how we should be looking at movement and more importantly, what we should be doing about it.  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 also a Brazilian Jiu Jitsu purple belt and complete BJJ/MMA junkie. 

Monday, April 20, 2020

Psychological Measures for Return to Play Following ACLR - Part VII

Last week, we continued our discussion on measuring kinesiophobia in our athletes and certain patient reported outcome (PRO) tools we could use to do this.  We specifically discussed several studies by Webster et al related to the ACL-RSI (Anterior Cruciate Ligament Return to Sport After Injury).  This is a PRO tool that is used to assess psychological factors which put the athlete at risk for injury with Return to Sport (RTSport).  The ACL-RSI is a great tool, however the one that I use the most (exclusively) is the TSK-11.  This decision was based on the Paterno et al Sport Health 2018 study, which showed that poor performance on this PRO (TSK-11) is highly associated with increased risk for re-injury with RTSport.  Athletes scoring >19 points on this test were 13xs more likely to get re-injured with RTSport.  We also know from the Noehren et al Orhto J Sport Med 2018 study that athletes who perform poorly on the TSK-11 also alter their movement patterns.  This study showed athletes tend to unload the effected side when kinesiophobia is high.  This is very similar to what we see on the TSK-11 and when we measure movement, specifically single limb performance. 

However, this is a frequent question that I get.  Why do you use the TSK-11 over the ACL-RSI?  Again, I think both of these are great.  However, I want to specifically look at psychological factors that I think have an impact on movement which I think equates to risk of re-injury as well as impacting performance of the athlete with RTSport.  The ACL-RSI has not been shown to be associated with movement patterns we know put athletes at risk or performance measures.  A recent study further confirmed, for what I am attempting to assess, that the TSK-11 is the preferred tool over the ACL-RSI.

O'Connor et al Am J Sports Med 2020 looked at the relationship between the ACL-RSI scores and measures of strength and power scores after ACLR in athletes. 

Methods:
This study recruited 452 male athletes who underwent a primary (first time) ACLR.  Subjects all had surgery at the same practice by two orthopedic physicians specializing in ACLR.  Athletes ranged in age from 18-35, had either a patellar tendon graft or hamstrings graft and planned on returning to sport.  All subjects were tested at 9 months and completed an ACL-RSI prior to testing. 

Prior to testing, each completed a warm up consisting of 2 minute jog, 5 body weight squats, 2
submaximal and 3 maximal single leg counter jumps. 


Testing consisted of:

  • Jump testing onto a force plate.  Testing was first completed on the non-operative leg then the operative side.  
    • 2 submaximal single leg counter movement jumps
    • 3 maximal single leg counter movement jumps
    • Single leg drop jump from 20 cm step with instruction to jump as high as possible
  • Isokinetic testing - performed in the seated position to get peak torque for quadriceps and hamstrings - 3 sets of 5 reps
Power variables included single leg counter movement jump height and single leg drop jump height.  Strength measures included isokinetic testing of hamstrings and quadriceps.  Operative and non-operative sides were compared on all measures to determine limb symmetry index (LSI).   


Results and Discussion:
ACL-RSI scores had little or no relationship with athlete's strength and power measures.  There was no meaningful difference in strength and power between athletes that had low scores on ACL-RSI and those that had high scores on the ACL-RSI.  The authors suggest that psychological recovery and physical recovery after ACL reconstruction are different constructs and each should be measured separately. 

This is where I could not disagree more.  Based on clinical experience and what we are seeing when we "objectively" measure movement is that these two are highly correlated.  Faulty movement has a negative impact on performance (decrease in power output and strength) and when we improve strength of the entire kinetic chain (from the foot to the core), we see an improvement in movement and an improvement in power output.  We also know these movements are directly associated with injury risk.  So, is it that these two things operate completely separately or is it that this particular PRO tool is not measuring it well.  Based on what we see, I would say more the later. 

So, to answer the question, this is one more reason that I tend to use the TSK-11 over the ACL-RSI.  It is more tightly associated with injury risk (with RTSport) and movement.  Eventually, I think we will see an association as well with power output.  I hope you have enjoyed this series and stay tuned as we continue to look at how we can impact both performance and injury prevention.  If you enjoyed, make sure to keep up with me on Instagram @bjjpt_acl_guy, twitter @ACL_prevention and on the web at www.drtrentnessler.com where I post the most up to date research and information.  #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 RTSport, 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 and speaks nationally and internationally on the subject.  He serves as the National Director of Sports Innovation for Select Medical and serves as movement and injury prevention consultant for numerous colleges and professional teams.  Trent is also a competitive athlete and purple belt in Brazilian Jiu Jitsu.