Sports Therapy
Dr. Trent Nessler

Physio Sports Blog

What moves you to stay in the game? Dr. Trent Nessler, National Director of Physio Sports Medicine, shares his calling and passion for injury prevention and performance enhancement using the most current research and technologies available. As a passionate educator, he is driven to share with all the latest peer reviewed journals in sports medicine and orthopedics and what that means to how we train and treat our athletes.

Movement Efficiency in Mixed Martial Arts - Part III

Last week, we started our discussion about how we assess movement efficiency in the MMA athlete and how that may guide some of our training.  As we described last week, core strength is critical in mixed martial arts for both performance and injury prevention.  The side plank test is an exceptional test for assessing the strength and endurance of the core and is often an exercise that is also used as a part of our training.  This is a great exercise as there is a lot of EMG activity of the gluteus medius, internal obliques, quadratus laborum and transverse abdominus.  During this movement, the EMG activity of the gluteus medius is very high and this is a critical muscle in stabilizing the core/hip/lumbar spine.  The gluteus medius is the muscle that assists in stabilizing the pelvis during single leg activities.  Here we see an athlete demonstrating a retrotrendelenburg, where you can see an arc from his upper body to lower body.  This should be straight and when performed in this fashion this a movement pattern that adds to weakness of the gluteus medius.  If this poor movement pattern is repeated over and over with every repetition and every training session, then this results in the athlete not training the muscles he is setting out to train and the impact on performance will be less than optimal.

This week we will continue this discussion as we look at assessing power generating movements and single limb performance.  Considering this, one of the first movements we want to look at is the squatting motion.

Squat – In this test, the athlete is asked to perform 20 repetitions of a body weight squatting motion.  During this test, you are assessing the ability to perform a squatting motion without a lateral shift (if a plumb line from cervical spine to sacrum is envisioned, the hips should remain equal distance from the plumb line throughout the motion).  If there is deviation to one side or the other, this is referred to as a lateral shift.  



Video – in the following video analysis we see an Olympic athlete demonstrating a right lateral shift during the squatting motion.  This same motion is carried over to training and athletic performance.  




Rational:  The squat is a critical motion for athleticism.  Improvement in the efficiency of the squatting motion has not only been shown to be associated with a reduction in injury risk but also associated with improvement in vertical jump and sprint speed.  Reduction of a lateral shift results in symmetrical force attenuation and improved symmetrical force production.   For the MMA athlete, this means greater force which can be generated with kicks and faster and more explosive takedowns.  In addition, a lateral shift can indicate loss of motion in the ankle, knee or hip on the side they are shifting away from.  This can guide preventative techniques which aid in reducing non-contact injuries during training and fights.  In this picture, we see the athlete from the video shifting to her right side which could indicate a loss of motion in the left hip, knee or ankle.

Training Impact:  For training purposes, the athlete is asked to squat using a resistance they can control throughout their range of motion without a lateral shift.  If an athlete has a lateral shift, simply loading that and allowing them to continue with will result in greater variance in asymmetry right to left, bigger impact on athletic performance and increased injury risk.  Once proficiency is maintained at a given weight, the athlete is then progressed through progressively increased loading.  If a loss of motion is considered, this could also guide some additional mobility exercises that can be performed.  If there is a suspected true loss of motion at the ankle, you would most likely see an asymmetry in the ankle motion in the plank test discussed previously.  This will appear as an increase in plantar flexion on the suspected side during this test.  In the training example here, this MMA athlete is doing a weighted squatting motion with kettle bells.  Although this is a great exercise, the problem is that he is shifting to his left side during every rep. Allowing him to do this during his training is just adding to the problem and accentuating his asymmetry.

Next week, we will begin the discussion of single limb testing and look at ways we can assess these athletes and how this can guide our training.  If you enjoy our blog, please share the passion and follow us on Instagram @BJJPT_acl_guy or on Twitter at @acl_prevention.


Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >5000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training.   He is also a competitive athlete in Jiu Jitsu. 


Movement Efficiency in Mixed Martial Arts - Part II

Last week we started the discussion on movement efficiency in MMA and we finished with the question, So, how do we assess that?  So this week, let's begin to take a look at some of the movements that we assess in these athletes and how these equate to injury prevention and performance enhancement. 

Testing the MMA athlete

Plank - In this test, the athlete is placed in neutral spine and neutral hip position, feet all the way together and head neck in neutral position.  They are then asked to maintain this position for one minute period of time. 

Rational:  The plank is a critical position for assessing the stability of the core.  The goal of this test is for the athlete to be able to stabilize while maintaining neutral spine position and neutral hip position.  In this test, the athlete must sustain stability this position within 10⁰ of flexion and extension AND rotation.  Maintaining stability in flexion, extension and rotation is critical to provide stable base for the lower kinetic chain to pull on, to generate force from and allow efficient kinetic energy transfer across the entire kinetic chain.

Training Impact:  For training purposes, the athlete is asked to start training this basic movement correctly.  The key to training is to ensure the athlete is maintaining neutral spine and hip position throughout their training.  Once this achieved, movement and resistance can be added to this movement.  In addition, the push up portion of the dynamic sumo stretch has a big carry over to this test therefore it is critical to ensure this movement is being performed correctly.  Once this is perfected, an exercise like the plank crawl is a great addition to the MMA athlete’s core training routine. 

Plank Crawl

Next we need to look at the core's recruitment in in combination with the pelvic and hip musculature.

Side Plank – In this test, the athlete is place in the neutral spine position ensuring that the athlete is not in a retro-trendelenburg position.  The feet are placed on top of one another and the non-weight bearing arm is placed on the hip.  Head and neck are maintained in a neutral position.  They are then asked to maintain this position for one minute period of time. 

Rational:  The side plank is a critical position for assessing the stability of the core and the endurance of the gluteus medius.  The goal of this test is for the athlete to be able to stabilize while maintaining neutral spine position and neutral hip position (hips not rolling forward or back).  In this test, the athlete must sustain stability this position within 10⁰ of lateral sidebending (moving hips up or down toward the surface) AND rotation.  Maintaining stability is critical to provide stable base for the lower kinetic chain to pull on and to aid in preventing internal rotation of the lower kinetic chain in single leg stance activities.

Training Impact:  For training purposes, the athlete is asked to start training this basic movement correctly.  The key to training is to ensure the athlete is maintaining neutral spine and hip position throughout their training.  Once this achieved, movement and resistance can be added to this movement.  Once this is perfected, an exercise like the side plank with the CLX is a great addition to the MMA athlete’s core training routine. 

Side Plank with CLX


Next week, we will begin the discussion and look at ways we can assess these athletes and how this can guide our training.  If you enjoy our blog, please share the passion and follow us on Instagram @BJJPT_acl_guy or on Twitter at @acl_prevention.

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >5000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training.   He is also a competitive athlete in Jiu Jitsu. 

Movement Efficiency in Mixed Martial Arts

Throughout the history of this blog, we have talked about how movement assessment can be used in injury prevention and aid in performance enhancement.  The association to sports like soccer, football and basketball are often easy for us to see.  However, sometimes we think there are certain sports that may be immuned to or which this does not have as much application to.  As a fan of MMA (mixed martial arts) and a student of BJJ (Brazilian Jiu Jitsu), coaches and athletes that specialize in these arts often think movement assessment has little application or that the sport is beyond it.  However, these sports more than any other are dependent on quality of motion for ultimate performance and for injury prevention.  Yet those that do use movement assessment for the sport often rely on outdated methodologies and primarily subjective measures.

Looking at the stats related to MMA and ACL (Anterior Cruciate Ligament) injuries we find some interesting key points.  Most would tend to believe that most ACL injuries in the UFC or MMA occur with contact.  A leg kick, knee bar or something of that nature.  However, the reality is that most of the ACL injuries in MMA are non-contact in orientation.  >70% of these injuries occur during a non-contact mechanism in training or during take down in a match.  One of the most common combinations of movements associated with ACL risk is valgus and internal rotation that occurs at the knee. 

As depicted here in the basketball athlete, this is sometimes easily seen in single leg stance or single limb activities.  Most often we see this in running, cutting and jumping activities.  Likely we have all seen a news reel or instant replay where a football or basketball player have a cutting movement resulting in these movement patterns and associated ACL injury.  But how does this apply to the MMA athlete and how do we identify?  Often these athletes are in such close contact with one another and the movement occur so rapidly that it is difficult to identify.  

As previously mentioned, the majority of non-contact ACL injuries in MMA occur with takedown.  As depicted in this picture, as the athlete shoots forward with his left leg, grabs his opponent and drives forward with the hips, this is when the injury occurs and usually to the stance leg (in this instance the left leg).  It is the point where you are driving the hips forward that the knee will tend to fall in toward midline.  This position not only creates a valgus stress at the knee but also results in an internal rotation moment.  The combination of these two movements creates a tremendous amount of shearing stress to the ACL and the meniscus of the knee.  Since these tissues are weakest in resisting of shearing forces, this is where a tear or rupture often occurs.  Obviously, optimizing the technique is critical to performing correctly but identifying where the weaknesses are in the system will aid in preventing these pathological movements during.

Are knee injuries and ACL injuries that common in the MMA?  This slide here represents just a few of the ACL injuries that have occurred in the UFC over the last 8 years.  Some experts associate injuries to these athletes to equate to ~$118M in lost revenue.  This loss in revenue associated with pay per view losses, sponsorships, etc. associated with each of these fights.  Considering this, >70% of non-contact injuries in these sports (MMA, BJJ, Karate) occur to the lower kinetic chain with the knee representing ~80% of those.  According to Harris et al Sport Health 2013 and Read et al Am J Sports Med 2017, professional athletes who suffered an ACL injury had a decrease across all performance measures after returning to sport following an ACL reconstruction and had a shortened athletic career as a result.  In professional sports, this meant reducing not only their professional career by 2-4 years but also the income they could get during that time (as a result of the decreased athletic performance).  When considering future performance as well as longevity of an athletic career, then obviously prevention of an ACL injury is critical.  Considering the majority of these injuries are non-contact in orientation, then this is why we focus on non-contact injuries.  In addition, non-contact injuries are also the ones that are most dramatically impacted (reduced) when properly identified and trained.  Another aspect that makes MMA so susceptible to lower limb injury is the association of concussion and lower limb injury.


This really started to come to light in 2016 when Brooks et al Am J Sport Med and Gilbert et al Sport Health both published studies showing that athletes who suffered a concussion where at greater risk of lower limb injury.  Not just a little but 1.6 to 2.9x greater risk of injury up to two years post-concussion.  This is despite the fact that cognitive testing (Impact test which is used to determine an athlete’s ability to return to sport) had returned to base line levels.  Considering that concussed athletes were found to be at greater risk of lower limb injury up to 2 years post-concussion, it makes us wonder how we could better test and train those athletes for safer return to play.  The initial studies showed similar results in Division I athletes and further studies by Pietrosimone et al Med Sci Sports Ex 2015, Cross et al Br J Sport Med 2016, Nordstrom et al Br J Sport Med 2016 showed this had similar applications in professional football, lacrosse and soccer players respectively.  Studies are showing that these athletes, despite unremarkable (meaning no signs of concussion) neurocognitive testing, when tested in single leg stance, their performance is greatly altered.  Kristinaslund et al. Am J Sport Med 2013 and Myers et al Am J Sport Med 2012 showed that single limb performance was the single best test for assessing movement associated with successful performance in sport and movement associated with risk.  Further, Howell et al Am J Sport Med 2015 may have discovered some of the underlying cause for altered single limb performance post-concussion.  In this study they found athletes who had suffered a concussion had a greater displacement of their COM  (center of mass) during single limb tasks.  As depicted here, this displacement of COM alters force distribution through the lower limb which alters force production (performance) and force attenuation (injury).  Considering, this not only guides us on how we should assess but also how we should train.

Next week, we will begin the discussion and look at ways we can assess these athletes and how this can guide our training.  If you enjoy our blog, please share the passion and follow us on Instagram @BJJPT_acl_guy or on Twitter at @acl_prevention.

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >5000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training.   He is also a competitive athlete in Jiu Jitsu. 

How Will Your NFL Team Perform? - Know Their Injury Rates - Part II

Last week we talked about the Read study and some of the implications that an ACL injury can have on an athletes performance after RTPlay.  This week, we are going to disect this a little more the investigate what this means to the team and to the player.

Players starting in less games.  One thing the authors spoke about was that players r
eturning to sport post ACLR started less games following RTPlay.  This can come from multiple factors including a coaching decision, a medical decision or player decision.

  • Coaching decision.  The coach may choose to not start the player due to their current performance.  They see that the player is making less tackles which means more players are getting by them which may result in more yardage per carry for the opposing team or TDs.  Net result is a decrease in the team’s performance.  The coach may also see that one of their star players is no longer one of their star players.  Coaches are there to win games and that depends on results of the individual players.  If a player’s stats drop, that means an opportunity for another player to move up.
  • Medical decision.  We know that athlete who have an ACLR are at greater risk for other lower kinetic chain injuries.  They also tend to have more knee problems and knee pain with RTplay.  This may result in the ATC or MD pulling them out of play or modifying their play based on how their knee is responding.
  • Player decision.  This is one that typically does not last long.  If the player is self-limiting their play, they may be pulled by the coach or cut from the team.  A lot of times, athletes will suffer from Kinesiophobia (fear of movement) after an ACLR.  This is where the athlete has not developed 100% confidence in their knee and its ability under the high demands of this sport, so they may self-regulate.  This is most common with those who suffer a non-contact ACL injury and typically have kinesiophobia with explosive movements and cutting movements.  Net result is a decrease in agility which may be one reason for a decrease in number of solo tackles.

Considering the above, what is the overall impact to the team and does this impact team performance.  Keeping in mind what this study showed us, one of the things we know is that the athletes that did return to play were the better defensive players prior to their injury.  That said, this study also clearly shows they did not return to the same level of play.  For defensive players, one of the game performance measures is number of solo tackles.  The number of solo tackles dropped dramatically and brought their individual ranking down from a star player to an average player.  Taking star players out of the game can and will have a dramatic impact on overall team performance in individual games as well as overall seasonal performance.

On a personal level, what is the impact to that athlete?  This is obviously the individual that is impacted the most.  NFL players know this impact and it is one reason that in 2014 and 2015, knee injuries were ranked the #1 concern among NFL football players in the NFL Players’ Association.  This is above concussion or any other injury.  Why?  Because they know how much this impacts earning potential.  This has a direct impact on the NFL player’s earning potential in 2 ways.  If their contract is up for negotiation, this is going to be based on prior year’s performance.  If they are starting in less games and making less solo tackles, then they do not have as strong negotiating power as they may have had previously.  In addition, what this study shows and what the athletes know, is that their professional football career is cut short.  Although this study shows an impact, what industry experts say is that their professional career may be reduced by 3-4 years.  On a multimillion dollar contract, that is a lot of potential income that they lose out on.

So why is this study so important?  ACL injuries are common in the NFL.  How common?    Let’s look at the numbers by season. 
  • 2016/17 – 46 ACL injuries 
  • 2015/16 – 48 ACL injuries  
  • 2014/15 – 45 ACL injuries 
  • 2013/14 – 63 ACL injuries

Over four seasons that is 202 ACL injuries.  If you look at the overall cost of those injuries, you must look at time loss, ACLR cost, rehab cost, positional replacement costs, emotional capital and impact to team performance.  Industry experts put this cost at ~1M/player.  Over 4 seasons, that is $202M in injuries.  

Sadly, over 73% of those are non-contact in orientation.  Studies suggest that you can reduce non-contact ACL injuries by as much as 80% if those athletes are properly identified and put on an appropriate program.  So over four seasons, that is a potential $118M cost savings if they had been identified and trained appropriately. 

So why is this not being done?  One is time.  How do you do that efficiently?  Here is an interesting fact.  66% of all NFL ACL injuries are associated with 5 positions. 
  • Wide receivers – 19.4% 
  • Linebackers – 15.5% 
  • Cornerbacks – 11.7% 
  • Offensive lineman – 10.7% 
  • Defensive ends – 8.7%

What does it take to make a change?  First and sadly, you need to tie it to performance.  How does this impact athletic performance, team performance and revenues.  The above study highlights the impact this will have to the individual performance of the player but also the impact this will have to the team’s overall performance.  Secondly, we need to know we can somehow efficiently identify those at risk.  With the advent of wearable sensor technology and the knowledge that 66% are associated with 5 key positions, then we now have an efficient manner to address.  Finally, having a solution.  Once those at risk have been identified, how do we change that?  There are multiple programs out there that can efficiently impact these pathokinematics and improve the movements that put athletes at risk. 


Insanity - To do the same thing over and over and expect a different outcome.  Is it time for the insanity to be over or are we going to continue what we have always done and expect a different result?  I chose the former.  


Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >5000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training.   He is also a competitive athlete in Jiu Jitsu. 

How Will Your NFL Team Perform? - Know Their Injury Rates - Part I

Over the course of our last series “Is there a secret sauce” we provided some thoughts and research on several factors that contribute to altered biomechanics or pathokinematics that put athletes at risk for an Anterior Cruciate Ligament (ACL) injury.  Throughout the history of this blog, we have attempted to correlate these same pathokinematics to not only ACL risk but also to changes in athletic and team performance.  In this authors mind, there are two ways in which this impacts performance; directly or indirectly.

The direct impact is the impact that altered biomechanics has to force production and kinetic energy transfer.  This direct impact results in muscles of the core and lower kinetic chain producing less force.  This is the results of several factors including changes to length tension curves.  Simply stated, due to the altered mechanics, the muscles of the core and/or lower kinetic chain are placed in a shortened or lengthened position.  Knowing the impact that length (shortening or lengthening) has on force production, then the muscle cannot produce as much force or power as it could if it were in an ideal length tension relationship.

The indirect impact is after the injury occurs.  The altered biomechanics resulting in a non-contact ACL injury result in an impact on future athletic performance.  However, this concept of how these injuries impact future performance has not been fully investigated.  That said, more and more studies are starting to investigate the impact on future athletic performance.

Case in point, a recent study by Read et al, Am J Sport Med2017, the authors looked at the impact of ACL injuries have on future performance in National Football League (NFL) players. 

Methods:  38 NFL defensive players with a history of Anterior Cruciate Ligament Reconstruction
(ACLR) from 2006 to 2012 were identified.  For each injured player, a matched control player was identified.  For each player, demographic and performance data was collected.  Players that returned to play (RTPlay) after ACLR (N=23) were compared to players who did not RTPlay after ACLR. 

Results:  At least 74% (28/32) players who had an ACLR RTPlay in the NFL for at least one season game.  61% (23/32) successfully returned to play for at least half of the NFL season (min of 8 games).  In the seasons leading up to their injury, athletes who successfully returned to play started a greater percentage of their games (81%) and made more solo tackles per game (3.44 6 1.47) compared with athletes in the ACLR group who did not return to play.  Athletes in the ACLR group retired significantly earlier and more often after surgery than the matched control group.  In the season after ACLR, athletes who RTPlay started games 57% less times and had only 2.38 solo tackles per game compared to matched controls at 3.44 solo tackles per game.

Conclusion:  Athletes who successfully returned to play were above average NFL players before their injury but not after. 

Next week, we will start to dissect this a little more.  Specifically what does this mean to the team's performance as well as the athlete's overall earning potential.  If you are enjoying our blog, please share it and follow us on twitter @ACL_prevention and on Instagram at @Bjjpt_acl_guy 


Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >5000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training.   He is also a competitive athlete in Jiu Jitsu. 


Is There A Secret Sauce? - Part VI

Gradients of Gluteus Medius Weakness – Part III
In our last couple of blogs, we have talked about the function of the gluteus medius in both an open kinetic chain and closed kinetic chain.  We have also talked about how this muscle functions on both the femur and the hip and how weakness of this muscle will present itself at the femur versus at the hip.  Although most understand the movement that occurs at the femur, identifying weakness that is represented at the hip is just as critical as it is at the femur.  With the shear stresses that are imparted to the labrum of the hip during these motions, hip motion can have just as devastating effect on the hip as the movement can have on the ACL at the knee. 

So now that we have identified it, how do we strengthen it?  Easiest thing is to look at the function of the muscle.  Before we get into specific exercises, let’s say one obvious thing, if you are going to strengthen this muscle, do it right!  Every single day, we see physical therapists, athletic trainers and personal trainers who do these exercises wrong and just strengthen bad or compensatory movement patterns.  In these cases, it is better to not do it than to do it.  Because strengthening bad movement patterns sets them up for greater risk.  To increase recruitment or maximal volitional contraction (MVC) of the gluteus medius, we need to think of it not just as strengthening the muscle.  You have to change recruitment patterns and sequence of firing.  Yes strength is a part of that but only a part.  To change MVC during functional movement you must change motor plans in the primary motor cortex. 

In 1998, Karni et al showed that in order to change a motor plan in the primary motor cortex (PMC), it required 3,000 to 30,000 repetitions.  The authors also showed that you can employ techniques which result in quicker change and that there are also things that we do that will result in slower changes.  From this, we have developed a saying.

Poor Technique = Poor Motor Learning = Poor Performance

Learn it, live it and teach it.  Change in the PMC is critical to change how the muscle fires during movement.  Based on the science, we know for every repetition that you do incorrectly, you then must do three reps to have a positive change on the PMC.  Considering this then, you must do one rep to offset the bad movement, one rep to offset the previous bad rep and one rep to drive a positive change in the PMC.  Sounds simple enough right?  Sadly, even with highly educated individuals, we typically see athletes doing the exercise incorrectly under direct supervision.  We then wonder why their movement has not improved that even when we are focusing on the right area and muscles.  Identifying the previously mentioned movements is hard enough when doing it in an assessment let alone when we are doing exercises.   There are numerous exercises to strengthen the gluteus medius in both an open kinetic chain and closed kinetic chain.  Therefore, we will only cover two exercises in depth which work on the gluteus medius in a closed kinetic chain. 

One such exercise, we call the lumbopelvic disassociation (LPD).  You can view a video of this on our YouTube channel, by clicking here.  This exercise is intended to do several things:

·        Assist athletes in discerning lumbar motion from hip motion by improving proprioception through the hip
·        Provide a closed kinetic chain exercise to start strengthening the gluteus medius

The video is intended to give viewers some pointers.  Although the athlete may do it incorrectly, this video’s intent is to not only show the exercise but to show where people go wrong.  This said, there are some common mistakes that people make in performing this exercise and which we can look for during performance of.  Once you have viewed the video, take a look at the athlete in this photo performing the exercise, you see several key factors. 

·        Stance knee is slightly flexed – most want to hyperextend to create stability
·        Knee/ankle/foot are stable
·        Non-stance leg is extended – this places the lumbar spine in extension and aids athlete in keeping neutral spine and not going into lumbar flexion during. 
·        Chest is up – promotes thoracic extension which also promoted lumber extension
·        Hips are level

If you compare the above athlete to the athlete pictured in the next photo, you can see some slight variations that also lead to strengthening compensatory strategies.  Keep in mind, this athlete is demonstrating minor deviations and is not even close to the magnitude of deviations that you would typically see when someone does this incorrectly.  We use this example because it is even these slight changes that result in significant impacts to the MVC of the gluteus medius.  In this case what we see is:

·        Non-stance leg in extension and chest up – good
·        Neutral spine position – good
·        Retrotrendelenburg position of the right hip – indicated with the yellow circle and seen with the hips not being level and the left hip coming up (placing the right hip in a retrotrendelenburg position)
·        Externally rotated position of the right foot – indicated with the red circle

The combination of the raising of the left hip and the external rotation at the right foot makes the retrotrendelenburg much greater at the right hip.  If we allowed him to continue this with all of his training, we can anticipate that when he performs in single leg stance or single limb tests, that his natural tendency is going to go into a retrotrendelenburg on the right when performing single limb tests on the right.  The simple correction is having him bring his right foot in slightly and drop his left hip down slightly. 

What is pictured above is a retrotrendelenburg but keep in mind that this can also present itself as a trendelenburg.  Easiest way to see both of these is to simply look at the hip position.  Are the hips level during the course of this exercise?  You have to watch closely during the beginning phases of this exercise as it may present itself here as the athlete rotating their hips out.  If they do and we allow them to continue that, then we are again just reinforcing the bad movement patterns and strengthening their compensatory strategies. 

Another common exercise used to strengthen the gluteus medius in a closed kinetic chain is side-stepping with a theraband.  In this video, we again go through some specific pointers related to the technique and compensations.  Even though this is one of the most widely used exercises for gluteus medius weakness, it is also one that is often performed incorrectly a majority of time. 

Some of the most common mistakes seen during this exercise are pictured here:
·        Having the band to high – higher the band is, the easier the exercise is.  Placing the band at the ankles not only makes the exercise more difficult but also brings in higher recruitment along the lower kinetic chain.
·        Band too loose – if the band is not tight at the starting position, it will be too easy throughout the motion and only stress the muscle at its weakest point in the length tension curve.
·        Lack of core activation – keeping in mind the concept of specificity, if we train with increase in lumbar lordosis (lack core activation) throughout this exercise then this promotes lack of core activation when it matters the most.
·        Allowing compensation during performance of the exercise.  Common compensations are:
o   Externally rotating with stepping out – this allows increased recruitment of the hip flexors and reduces MVC of the gluteus medius
o   Standing when bringing feet together – this is a much easier position for the movement and maintaining this position throughout will aid in increased MVC.  

Taking these few pointers and applying to your gluteus medius strengthening will not only make a huge difference in what the athlete feels but also aid in improving their mechanics with CKC movement.  We hope that you found this blog insightful and useful.  As we stated previously, stay tuned and if you like what you see, SHARE THE PASSION!  It is the biggest compliment you can give.  Follow us on Twitter @ACL_prevention and tweet about it.  #ACLPlayItSafe and help us spread the passion.

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >5000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training. 



Is There A Secret Sauce? - Part V Cont

Gradients of Gluteus Medius Weakness – Part II
Last week we discuss the function of the gluteus medius in both an open kinetic chain and closed kinetic chain.  Now that we know the function of muscle, what kind of movements will we see?  The most obvious is adduction in the frontal plane (like pictured in the above athlete).  When we see movement like that and we have identified it is coming from the hip and not the foot, we know that the gluteus medius is playing some role in that.  But what about the cases where the lower limb (femur) is stable?  We know that the gluteus medius also has an impact on stability at the pelvis, so what kind of movement would we see at the pelvis and if we see movement at the pelvis, does varying movements indicate a gradient of strength of the gluteus medius? 
According to Palastanga et al, we know that the gluteus medius “controls” pelvic rotation when the lower limb is stabilized.  It is well accepted in the literature as well as the medical field that weakness of the gluteus medius can result in a trendelenburg at the hip during gait (walking).  In the example pictured here, the right hip drops during stance phase on the left leg.  The arrow indicates that it is weakness of the gluteus medius on the left side that allows the pelvis to drop on the right.  With the origin and insertion of this muscle on the iliac crest and femur, shortening (or contraction) of this muscle would result in pulling the left pelvis down which would raise the right hip.  This is seen a lot in patients who have suffered a neurological insult (stroke) and who have a gluteus medius weakness as a result.  However, you can also see this in athletes.  In athletes, you will not typically see this in walking gait, but you will start to see this in running gait and in jumping.  Because of the ballistic nature of these movements, this occurs as a result of much higher ground reaction forces that occur with sports and are often much harder to see.  If you look at the high school football player pictured here, you can clearly see a trendelenburg that is occurring with a single leg hopping activity.  This trendelenburg is not apparent in his normal gait cycle.  However studies show that jumping results in ground reaction forces that are 4-8 times body weight whereas walking is traditionally 1 to 1.5 times body weight.  Hence, when we have an athlete do more difficult movements (single leg squat or single leg hop), then this lack of control at the pelvis then becomes more apparent. 
But, we also know that with greater weakness comes more significant deviation.  In the knee, this is represented as a larger increase in the frontal plane adduction and hence an increased adduction moment.  But, if the lower limb is stable, how does that appear at the pelvis?  Again, looking at some of the stroke literature, we know that patients who tend to have decreased MVC of the quadriceps that they hyperextend their knee.  Why do they hyperextend their knee?  Subconsciously, they have figured out that they cannot sustain a flexed knee posture so they hyperextend their knee to create more bony stability (created by bony stability with increased contact with femoral condyles and the tibial plateau).  This position, although it provides stability, also results in a decrease in MVC of the quadriceps.  Something similar to this occurs at the hip.  As pictured here, what you see is a retro-trendelenburg.  In this position, you see the athlete subconsciously position their center of gravity (upper body) further laterally which increases body stability (between the acetabulum and femoral head) and requires significantly less MVC of the gluteus medius.  As a practitioner or examiner, if you don’t look for this and you are only looking for adduction in the frontal plane as your indication of gluteus medius weakness, then you may miss an opportunity to not only reduce ACL risk but also risk for a labral tear in the hip.
With severe weakness come severe deviations.  In the knee, this means that adduction in the frontal plane is of such large magnitude that we are also now starting to see significant internal rotation of the femur.  But what does that look like in the hip?  In the hip, this results in a trendelenburg along with a rotation (what we define as a cork screw).  In this scenario, the gluteus medius is so weak that the pelvis drops and rotates at the same time.  Looking at the origin and insertion of the gluteus medius, the muscle is failing through its full range of motion and hence why these two movements occur in unison.  This is most easily observed by the position of the contralateral limb (non-stance leg).  If this leg comes way across midline like this, then there is both a component of hip drop as well as rotation that is occurring at the hip.  In these cases and under high loads (jumping and running) the amount and magnitude of shear stress that is imparted to the labrum of the hip significantly higher than it is intended to take or that it is designed to take.  In this volleyball player pictured here, you can clearly see the trendelenburg and rotation occurring in both single leg squatting motions as well as in single leg hopping motions.  That said, not only is this athlete at risk for ACL injury but also hip injury.  As a practitioner or examiner does not look for this, then they are missing an athlete that is at high risk for injury, especially in sports that require running and jumping. 
Considering all the above, we can now grade our gluteus medius weakness based off the deviations that we see presented at the pelvis as much as what we see at the knee.  At the pelvis, we would expect the following gradients:
  • Trendelenburg – mild/moderate gluteus medius weakness
  • Retrotrendelenburg – moderate to severe gluteus medius weakness
  • Cork screw – severe gluteus medius weakness
Ok, so now we have it but what does all this mean for strengthening? Stay Tuned!
We hope that you found this blog insightful and useful.  Stay tuned next week we will discuss how do we train the gluteus medius in both an open kinetic chain and closed kinetic chain.  As we stated previously, stay tuned and if you like what you see, SHARE THE PASSION!  It is the biggest compliment you can give.  Follow us on Twitter @ACL_prevention and tweet about it.  #ACLPlayItSafe and help us spread the passion.

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >5000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training. 



Is There A Secret Sauce? - Part V

Gradients of Gluteus Medius Weakness
Throughout this series we have been discussing what the research tells us about what puts athletes at risk for injury.  Not that there is a secret sauce but more that it is a contemplation of complexity of the issue and plethora of factors to consider when looking at.  We have taken an in depth look of the current research to see what does it tell us and how we can use that knowledge to improve the outcomes with our interventions.  In the last 2 blogs, we spoke a lot about adduction in the frontal plane in single limb performance and how important this is to identify in our athletes.  We have also discussed how we can use this knowledge in our interventions so we can have better results.   
When looking at lower kinetic chain mechanics, one of the easiest factors to identify is adduction in the frontal plane.  Although the majority of research has been written around this deviation in relation to ACL injuries, we also know that this deviation has an impact on patellofemoral pain, non-contact ankle injuries as well as a shearing stress at the hip.  So often, we tend to get caught up in the complexity of the issue and try to dissect to the minutest detail.  Yet, is this really getting us anywhere?  What the research shows and what we know clinically is that when looking at the big picture, it is often the larger movements, that when corrected, have a larger impact on overall lower extremity mechanics than when we focus on the smaller minute movements.  For example, if we have a running athlete that demonstrates a significant amount of adduction in the frontal plane, slight pronation at the foot and lack of 5° of 1st MTP (metatarsal phalangeal) extension, correcting the adduction in the frontal plane will often do more for their injury risk and performance than focusing on the lack of MTP extension.  Is the 5° of 1st MTP important?  Absolutely but although both are important, in many cases, it is the larger movements that drive the smaller movements.
Over the course of the last 10 years, there has been a plethora of papers published looking at hip muscle activation and the impact that it has on adduction in the frontal plane.  Specifically, many authors have looked at the MVC (maximal volitional contraction) of the gluteus medius during such activities and found that decreased strength (decreased MVC) and endurance of this muscle adds to an increase in adduction in the frontal plane.  Although this has been well documented and vetted in the research, many still question the gluteus medius’ role in control of frontal plane motion.  However, 2013 in the Journal of Strength and Conditioning Research, Mauntel et al showed that there was an increase in knee valgus in those who demonstrated decreased hip adductor and external rotation strength.  They also found by increasing hip abductor and external rotator strength and endurance resulted in a decrease in knee valgus (adduction in the frontal plane) that was observed in single limb performance.  The authors suggest, based on previous author’s data as well as their findings that reducing adduction in the frontal plane by targeted strengthening to these muscles would and does reduce the risk for injury.  We also know that gluteus medius activation is also directly correlated to patellofemoral pain in athletes.  According to a study published in 2012 in the British Journal of Sports Medicine, Morrissey et al found that those who demonstrated decreased strength and endurance (EMG activity) of the gluteus medius had an impaired ability to control frontal plane motion at the knee.  Those subjects that demonstrated increased frontal plane motion were also more likely to complain of patellofemoral pain.  In other words, as depicted here in this athlete, sometimes the obvious answer is right in front of us and we need to just look.  Instead of trying to make a complex issue even that more complex, maybe we just look at the most obvious movement and find out how do we prevent that!  The interesting thing is, when you do, in a majority of the cases, the little things correct themselves. 
So, keeping with that philosophy, what muscle is it that results in a decrease in adduction in the frontal plane?  Some studies suggest the gluteus medius and some suggest strengthening the abductors and external rotators.  Are they one in the same?  To find this out, we must go to two of the leading resources in this area.  According to one of the most referenced experts in this area, F. Kendall Muscles testing and Function with Posture and Pain, we see that the manual muscle testing position for the gluteus medius in an open kinetic chain (OKC) is abduction, slight extension and slight external.  Knowing this, in an OKC, the gluteus medius is both an abductor and external rotator.  However, is this how the muscle functions in a closed kinetic chain?  To determine this, we must look at another leading source N. Palastanga Anatomy and Human Movement: Structure and Function.  According to Palastanga and due to both the attachment and fiber orientation of the gluteus medius, in a closed kinetic chain, it functions to both provide abduction and externally rotate the femur.  During single limb activity, it is much more important in stabilization in both abduction and external rotation (preventing adduction and internal rotation) and also controls pelvic rotation when the lower limb is stabilized.  From the function of the muscle, in both an open kinetic chain and closed kinetic chain, we can then determine what movements are associated with weakness of this muscle AND what types of movements will aid in strengthening of this muscle.
We hope that you found this blog insightful and useful.  Stay tuned next week we will discuss how to identify those movements at the pelvis and what that means.  As we stated previously, stay tuned and if you like what you see, SHARE THE PASSION!  It is the biggest compliment you can give.  Follow us on Twitter @ACL_prevention and tweet about it.  #ACLPlayItSafe and help us spread the passion.

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >5000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training. 



Is There A Secret Sauce - Part IV - Continued

Importance of Single Limb Testing – Cont.
Last week we started to discuss the importance of single limb testing.  This week, we will continue this discussion.  We will start off with a further examine of this concept of single limb testing versus bilateral, by looking at Myers work in 2012.  Myer et al published a paper in 2012 in the American Journal of Sports Medicine looked at asymmetries in single limb performance in vertical jump and associated force attenuation in athletes that were released to return to sport following ACL reconstruction.  What they found was that these asymmetries continue to be present and concluded that if they do persist, then this may increase the risk of either contralateral (opposite side) or ipsilateral (same side) injury.  So clearly, we have to be able to measure these deficits in a single limb fashion to even know they exist. 
So based on all this information, then it make sense that we should test single limb.  We also know from Stearns et al work in 2014, that adduction in the frontal plane is directly correlated to the adduction moment.  We also know from previous work that the larger the adduction moment then the greater the risk is for ACL injury.  Considering this, then when we look at single limb testing, we need to quantify adduction in the frontal plane.  Besides just the injury perspective, why is this important?  Consider this case in point.  If this athlete pictured here was a DI soccer athlete being recruited under a scholarship, do you think she would be at risk for injury?  If you say yes, what would make you say that?  If you say no, do you think this would impact her performance?  Considering both of these factors, would you want to know these conditions exist if you are spending your limited scholarship dollars on this athlete?  According to Rugg et al in AJSM 2014, athletes who have had a previous knee injury or ACL injury prior to their DI career are at an 8 to 800 fold increase risk of injury.  But outside a reported previous injury, how would you ever know that the conditions exist?  Although there are methods to test these things, current methods limit us from measuring this clinically or in mass pre-participation physicals with any degree of sensitivity. 
What is sensitivity?  The sensitivity of the test in this case is the ability of the test to demonstrate minor improvements or decreases in performance with a high degree of reliability.  Although some tests use the eyeball to quantify, some of the more sophisticated used 2D technology to quantify.  But, even if we use 2D technology to quantify performance on single limb testing, the ability to do it with any high degree of sensitivity is limited.  For example, with most tests, if you do one rep, three reps or 10 reps, the score is based off the worst rep observed during the sequence.  This makes sense using this methodology since it is the largest magnitude of the deviation that puts you at highest risk.  We also know that if you scored every rep, then this would not be a very efficient test and impractical for adopting as a standard of practice for mass physicals.  
But is scoring off one rep really sensitive?  What if you compared two athletes, one that did 10 reps and with each rep he/she had a large degree of adduction in the frontal plane versus an athlete that did 10 reps and only had one rep with a large degree of adduction in the frontal plane.  Which one of the athletes would you say is at greater risk? Obviously, we would all say the one in the first scenario since it is the same degree but occurs multiple times.  But if you were scoring only the worst rep, then on paper they would appear to be at the same level of risk.  So, how truly helpful is that information?  How can we account for that?  There is a couple of different ways to accomplish this.  One is to perform multiple single limb tests and to score every rep.  In this example, the three single limb tests consists of 10 reps per limb on each of the tests or a total of 30 reps.  With a recently introduced 3D technology, we are now able to score every repetition performed during each for the tests based on the degree of adduction in the frontal plane present.  Previously, performance on these three tests would give you a cumulative score of 9 points on the right and 9 points on the left.  But, by performing in this fashion with this technology, you now have a score of 90 points for the right and 90 points for the left.  By doing it in this fashion, this allows you to see minor improvements in movement on as little as one rep. 
By performing three tests in sequence, we can also put the easiest test first and the harder test at the conclusion.  It would make sense, in this sequence that those that fall apart on the earlier test verses the later would be at higher risk.   In this example then, we have two ways of capturing risk.  One is with a more sensitive test and one is through where the athlete falls apart in the sequence of tests.  Collectively, both methods bring to light ways in which we can apply the current research with methods and technology which can provide us with a much clearer picture of risk.
As much as we have talked in this SL testing portion, several key things for everyone to understand.   First is that if we can prevent injuries, we preserve the future joint health and opportunities for our athletes.   For many young athletes, their only opportunity for a higher education and life opportunities is a college scholarship.  If we can prevent injuries, we give them a better opportunity to do that.  The additional benefit of this approach is the impact that it has on performance as well.  It does not take a biomechanist to look at the athlete pictured above to see potential opportunities for improvement in performance.  Movement like this that is noted above results in loss of kinetic energy and decreased power output.  This means decreased sprint speed and decreased vertical jump.  If we have the opportunity to improve their future opportunities and their future performance, why would we not?
We hope that you found this blog insightful and useful.  Next week we wrapping up this series with a discussion on gradients of gluteus medius weakness and how do we indentify.  As we stated previously, stay tuned and if you like what you see, SHARE THE PASSION!  It is the biggest compliment you can give.  Follow us on Twitter @ACL_prevention and tweet about it.  #ACLPlayItSafe and help us spread the passion.

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >5000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training. 



Is There A Secret Sauce - Part IV

Importance of Single Limb Testing
Over the course of the last several weeks, we have been talking about how to apply the research to how we assess and treat athletes.  Whether we are strength coach, athletic trainer or a physical therapist, there is a way to take the current knowledge and literature and apply it in a way that is much more effective than the way we have traditionally done or do today.  For this discussion we are going to talk about single limb performance.
One of the hottest topics right now in sports medicine is when do you make a return to sport call.  Why?  Clinicians and physicians are becoming more and more cautious because re-injury rates are high with those who return to sport to early and the outcome on the 2ndsurgery is never as good as the first.  Why is this risk so high?  In a study published by Stearns et al in the American Journal of Sports Medicinein 2013, they looked at female soccer players that were cleared to return to sport following an ACL reconstruction.  What they found was that they still demonstrated increased adduction angles in the frontal plane which is directly associated with the adduction moment & risk.  The bigger the angle, the higher the moment which means the higher the risk is for ACL injury.  But this is only becomes clear when doing a comparison to the contralateral limb in a closed kinetic full weight bearing test (as demonstrated here). 
So, when do you know is the right time to return an athlete to sport following an injury or surgery?  Frankly, no one really knows.  There is a lot of debate about this issue because, as of today, we still don’t have a standardized way or protocol that we use in which can aid us in making that call.  Hence why so many athletes fail to return to their prior level of performance and why over 20% re-rupture their ACL within the first 2 years of returning to sport.  We know from the literature that you should be somewhere within 80-85% of your non-involved limb.  But how do we test that.  Today, that is mostly done off of subjective findings, subjective observations and an objective open kinetic chain computerized test (Kin Com for example).  In this particular test, the subject is seated in a device that looks like a computerized leg extension machine.  The subject performs both leg extension and flexion under resistance.  At the conclusion the computer provides a report showing symmetry or asymmetry between the two extremities.
If we consider the exercise physiology concept of specificity, then it would make sense that whatever test or tests that we do, we want to make sure it is as specific to the actual activity as possible.  Now, in a controlled environment and under testing conditions, it is often hard to truly mimic the activity in such a way that we can also get an objective measure.  That said, in most sports you are not in a seated position when your lower kinetic chain has to respond to a load and resist the stress.  When looking at the seated position versus the standing positions, the differences are clear.  There is change in length tension relationships along the entire lower kinetic chain from the core to the foot.  At the same time, recruitment patterns are completely different.  In standing your core is much more active and in seated position it is much less active.  We know that the core has a direct influence on the lower kinetic chains ability to attenuate force, so it would make sense that whatever testing we do should be in the upright position.  Considering all this then testing performed in the upright position is going to be much better than seated or laying down and will provide you with more accurate assessment of how they actually function.
Take this particular case in point.  This 16 year old basketball player who was previously seen for knee pain and patellofemoral issues was returned to sport after  a thorough examination by both her physical therapist and physician.  Her examination consisted of a review of her exercise program she was doing in therapy, her manual muscle testing scores performed on the table, her self reported outcome and measured range of motion.  However, she was not evaluated in a closed kinetic chain nor was her movement assessed during functional closed kinetic chain exercises.  In this case, upon return to sport, she demonstrated the following motion on a lateral pivoting motion which resulted in her rupturing her ACL.  Would she have demonstrated this motion on a functional closed kinetic chain test?  It is unknown nor can we speculate one way or the other.  What we do know is if you do not access closed kinetic chain motion, then you will never know.
If we were again to look at most sports and especially those that require running you will see a significant portion of it is single limb in nature.  Just looking at the running cycle, you can clearly see how most (all) of that is single limb in nature.  If we look at the epidemiology studies associated with non-contact ACL injuries, you will also see that most of these occur in a single limb position or a position where it is predominately single limb.  If we consider this factor alone, then it would make sense that if the mechanism of injury is during upright, full weight bearing single limb activity, then this should be how we test.   That said, Grindem et alpublished a paper in 2011 that looked at single limb testing versus bilateral testing to see which of these two were a better predictor of the athlete’s self-reported function.  Knowing that self-reported knee function was a fair predictor of risk, then seeing which test had a higher correlation to this self-reported function made sense.  What this study showed was that measurement of symmetry in single leg hop was a much better predictor versus bilateral hop.  The problem with testing athletes is that they are often very good at compensating in a way that it is hard to see, especially in bilateral tests versus single limb tests.  The higher the level the athlete the better their compensatory strategies are and hence why they are able to compete at a high level.    In this instance here, this athlete may have compensated for her lack of stability on the right by shifting her weight to the left during bilateral performance.  This could account for some of the results that we see in the current studies looking at bilateral performance in comparison to adduction seen in single limb.  This is clearer when looking at Kristinaslund et al 2013 study in which they looked at the bilateral drop jump and compared that to the adduction moment seen in sidestep cutting.  What they found was that there was only a moderate correlation to the adduction moments seen with bilateral jump and the overall adduction moment in the bilateral performance was significantly less.  The conclusion of this is that the bilateral jump is only a fair predictor but there is probably a better way to see what true adduction moments are in single limb.  That might lead us to the realization that maybe we should test single limb. 
Next week, we will continue this discussion on single limb testing and correlation to injury risk. We hope that you found this blog insightful and useful.  As we stated previously, stay tuned and if you like what you see, SHARE THE PASSION!  It is the biggest compliment you can give.  Follow us on Twitter @ACL_prevention and tweet about it.  #ACLPlayItSafe and help us spread the passion.

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >5000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training. 



Is There A Secret Sauce? - Part III

Key to Identifying the Weak Link!

Over the course of the last 2 weeks we have been talking about various aspects of movement assessment and how we can positively or negatively impact that.  In our first blog in this series we spoke of the influence that both verbal and non-verbal instruction have on movement.  Knowing this, we can use that knowledge to facilitate more efficient change in order to reduce injury risk and improve performance.  In last week’s post, we talked about the influence of fatigue and how we can use the fatigue and vibration research to facilitate more rapid change in poor movement patterns.  So, although there is not a “secret sauce” this knowledge can give you a significant advantage when it is applied to movement correction.  Is it secret?  Absolutely not!  Unfortunately the research has been out there for more than 10 years but it often requires us to look at it differently in order to apply to the techniques we use in the clinic, performance setting or on the field.  So although it is not done or a standard of practice does not mean it is a secret sauce.
As we go around the country and abroad teaching people about movement, one debate always seems to bubble to the surface when it comes to movement.  The debate is, does the adduction in the frontal plane (or valgus displacement) that is seen coming from the lower lower kinetic chain (foot/ankle) or the upper lower kinetic chain (hip/core)?  In other words, is the pronation and lack of dorsiflexion leading to the adduction in the frontal plane or is it from an issue at the hip/core?  This is a valid question and unfortunately is often driven by one’s training or perspective.  In 2011, Man Fong et alpublished a study in the Journal of Athletic Training that looked at dorsiflexion range of motion and landing biomechanics.  What they found was that those who had lack of dorsiflexion also had greater knee valgus displacement during landing.  The conclusion is that lack of dorsiflexion must then lead to increased risk of frontal plane motion.  This lead to a big push to assess ankle dorsiflexion in order to determine risk of ACL injury.  However, if we consider that age old debate “Was it the chicken before the egg or the egg before the chicken”, it requires us to consider all the factors.  It you talk to a podiatrist, you may hear that everything is driven from the foot and therefore adduction in the frontal plane can and will be controlled by strengthening and controlling the foot/ankle.  Conversely, if you talk to a physical therapist that sees everything at the hip, then you may hear that everything is driven from the hip and therefore adduction in the frontal plan can and will be controlled by strengthening and controlling the hip/core.  Although both approaches may have beneficial results, is the outcome as good as it could have been IF the root cause was identified?
For example, in the picture here with a DI soccer athlete, the lateral displacement of the pelvis to the right is going to cause an increase in dorsiflexion on the right and decrease in dorsiflexion on the left.  Over time and if this is carried over to all activity that requires squatting (which it does), then this will lead to decreased range of motion of the left ankle.  This will also lead to altered strength and proprioceptive development throughout the entire kinetic chain.  So, in this case, is it the lack of dorsiflexion that leads to the lateral shift and hence adduction in the frontal plane with single limb activities or vice versa?  How can we possibly know?
As difficult and as complex as the problem is, it really comes down to common sense.  The lower kinetic chain is a closed chain and anything that can affect the top of the chain will affect the bottom and vice versa.  Considering this, poor control at the ankle/foot can and will drive adduction in the frontal plane.  Conversely, poor control at the hip/core can and will also drive adduction in the frontal plane.  So how do you know what to address?  Considering the above and basic biomechanics, then the following two statements make sense.
·        In a closed kinetic chain, the weak link will fall first which will then be followed by the rest of the kinetic chain.
·        In a closed kinetic chain, the weak link in the chain will present with the largest magnitude of the deviation.
So, in other words, the weak link falls first and the link with the largest magnitude of deviation is the main driver of the movement that is present. 
In this example, we see a DI soccer player that is performing a 31cm step up.  As she starts to load the lower kinetic chain, what we see is significant adduction in the frontal plane.  If we view her ankle at this point in the motion, what we see is that her ankle is in a relatively neutral position.  Based on the fact that we see her hip falls into an adducted position first and that her hip has a larger magnitude of the deviation, we can then conclude that the “root cause” of the adduction in the frontal plane is the result of weakness or lack of stability at the hip.  If you watched this athlete throughout the entire range of motion, what you would see is that as she continued to load the limb (continued her step up) that her ankle eventually starts to move into a pronated position.  But this only occurred as the result of the increase in magnitude of the adduction that was occurring at the hip.

Using this same motion with the following athlete, we see a completely different presentation.  In this athlete, we see adduction in the frontal plane but we also see a significant amount of pronation at the ankle.  As she began to load the limb in the step up motion, what was noted was that she immediately pronated (arch collapsed)  as she started to attenuate force through the limb and as she continue to progress up through the range of motion of the step up, this pronation increased in magnitude.  What we also saw was a fair amount of adduction in the frontal plane.  So, in this particular case, the weak link (ankle) gave first and had the larger magnitude of the deviation.  Considering this, it is the lack of ankle stability and severity of the weakness that results in an increase in adduction in the frontal plane. 
In both of these cases, applying some common sense and basic biomechanics aids us in getting a clearer picture of the root cause versus basing our interpretation on a preconceived philosophy.  In both cases, had they been treated the same, both would have had positive results.  But, does positive results equate to optimal outcome?  Far too often the two are considered synonymous when they in fact are not.  If you identifying the weak link in the chain this will result in optimal outcome, longer and sustainable results and a greater impact on current and future athletic performance.
We hope that you found this blog insightful and useful.  Next week we will discuss the importance of multiple single limb tests for determining symmetry.  As we stated previously, stay tuned and if you like what you see, SHARE THE PASSION!  It is the biggest compliment you can give.  Follow us on Twitter @ACL_prevention and tweet about it.  #ACLPlayItSafe and help us spread the passion.

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >5000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training. 



Is There A Secret Sauce? - Part II

Using Fatigue to Drive Change

In our last blog we talked about how verbal instruction can influence movement.  Although this is good when we are attempting to improve movement, it is counterproductive when we are attempting to assess what is the athlete’s natural motion.  This week, we are going to discuss lateral shift and how you can use the research to assist us in correcting.
When evaluating human movement on a regular basis, you start to identify certain trends for normal movement and abnormal movement.  It is these deviations from “ideal movement” that have been researched for the last decade and which have been correlated to injury risk.  Reiman et al as well as others have linked proximal hip weakness and the adduction in the frontal plane that occurs as a result to be directly correlated to risk for knee and ACL injuries.  When viewing this example of an Olympic athlete, it is easy to see how she may be at risk for injury.  However, it has not been well accepted the impact that this also has on performance.  This despite the fact that Meyer et al as well as others have shown that improvement in these abnormal movements result in performance improvement, increased power output and strength gains.  If we think about the previously mentioned athlete and imagine that she is a sprinter, we can imagine the impact these movements would have on kinetic energy transfer, efficiency of movement and power generation with explosive power.  Although this concept is easy to see conceptually, it has not been fully vetted in the research.   
However, one abnormal movement trend we have not heard a lot about is the lateral shift that occurs with squatting motion.  For the last 12 years with our movement assessment, we have been describing and capturing this lateral shift of the pelvis that can occur with a squatting motion.  Never heard of lateral shift?  Unless you have been exposed to our blog or one of our courses, you probably have not.  However, in the last year, we have started to see it described in the literature.  In the May 2013 issue of the Journal of Strength and Conditioning, Atkins et al described a lateral displacement of the pelvis during the squatting motion (i.e. lateral shift).  The authors looked at this displacement during the squat and its impact on force distribution through the lower kinetic chain as measured with a force plate.  What they found, was greater force on the side the athlete shifted to and less on the side they shifted away from (in this picture more force on the right limb and less on the left).  So what exactly is a lateral shift? 
When an athlete is in stance and prior to initiation of a squatting motion a plumb line is dropped from cervical spine to lumbar.  This indicates midline.  During normal motion, the hips should be relatively equal distance from this plumb line throughout the motion.  If they are not and the athlete shifts to one side, this results in increase load to one side versus the other and altered force attenuation on one side versus the other.  This has both implications for injury risk and altered force production.  When an athlete demonstrates a lateral shift, this can also result in a lack of ankle dorsiflexion and knee/hip flexion.  In the Olympic athlete pictured above, you can see her shifting her weight to the right results in decreased ankle dorsiflexion on the left and increased dorsiflexion on the right.  In recent study in the Journal of Knee Surgery, Sports Traumatology, Arthroscopy, Mallory et al looked at ankle dorsiflexion and correlation to increased risk for ACL injury.  What they found was that those who demonstrated a lack of dorsiflexion also ended up with increase in adduction moment at the knee which increases ACL injury risk.  So is it the lack of dorsiflexion that is leading to the increased risk or the lateral shift that is leading to the lack of dorsiflexion which is also associated with risk?  Either way, capturing and correcting this movement is vital.  In this Olympic level athlete pictured above, you can clearly see the deviation to the right throughout the squatting motion.  This would be termed a right lateral shift and something that would be imperative to start correcting.  There are many potential causes for this lateral shift which is beyond the scope of this paper so here we are going to talk about correcting. 
Outside of a bony abnormality or bony block, we find that this can be corrected in as little as 2-3 sessions.  How?  First and foremost is showing the athlete the motion.  Whether you use a mirror or video, allowing them to identify the lateral shift on themselves is a critical part to the motor learning aspect as well as the compliance.  As the practitioner, also correlating this lateral shift to not only the injury risk factor but also the impact on performance is key. 
One thing that often happens when attempting to work with someone on correcting a lateral shift is they tell you “it feels weird”.  Why does it feel weird?  Proprioceptively, they have trained their body that the position of the lateral shift is normal or neutral.  So, as a part of their re-training, we must retrain their proprioceptive system to what is neutral or normal.  How do we do that in a way to make rapid changes?  If a part of the sense of weirdness is coming from proprioceptive input, then we can use the research to guide on ways to do that.  We know from the stroke literature that visual input can aid in motor learning and in correcting pathological movement patterns.  We also know from Lattanzio et al research in 1997 as well as others that fatigue results in decreased proprioception. Trans et al research in 2009 taught us that whole body stimulation and over stimulation can result in more rapid changes in proprioception.  So, if we could combine all this knowledge should we not have even better results.  If we use exercises that provide visual input, cause neuromuscular fatigue and overload the proprioceptive system with stimulation, shouldn’t we see even faster and more rapid changes?  That is exactly what you do see.  Implementing these concepts into your squat neuromuscular retraining will result in more rapid changes and allow you to correct a lateral shift in 2-3 sessions.  That is evidence based practice!
We hope that you found this blog insightful and useful.  Next week we will discuss how to determine the weak link in the system and using that to drive your intervention.  As we stated previously, stay tuned and if you like what you see, SHARE THE PASSION!  It is the biggest compliment you can give.  Follow us on Twitter @ACL_prevention and tweet about it.  #ACLPlayItSafe and help us spread the passion.

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >5000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training. 



Is There A Secret Sauce?

Let me start by saying, there is no secret sauce.  In this next series of blogs we will be providing you with what we would consider some unique methodology behind what we do.  Is it rocket science?  No.  We have simply taken what the research has told us for the last 12 years and applied it in a very unique way.  Over the course of the last 5 years, we have been blessed to perform movement assessments on over 5,000 athletes.  As such, you tend to see patterns or trends for what is normal and abnormal.  You tend to get a clear indication for what works and what does not work.  That is what this series of blogs will consist of.
Over the course of the next 5 weeks, we will provide some insight in the following areas:
1.      Impact of verbal instruction and video on movement assessment and outcomes
2.      How to integrate knowledge of fatigue research in correcting lateral shift
3.      How to determine weak link in the system
4.      Importance of multiple single limb tests to determine symmetry
5.       Gradients of gluteus medius weakness and how to assess and correct
So, let’s start with the first one.  I call this one “You Talk Too Much”.  When it comes to assessing movement, one of the biggest mistakes we make is over instructing athletes in movement.  What we want to capture is what is the athlete’s natural motion versus the movement that we tell them we want to see.  Natural motion is more reflexive (CPG driven) in nature versus motion which brings in a lot of higher center (cerebellum and PMC) input. 
You ever wonder why when you ask someone to squat and you describe that motion that we end up with this really funky movement.  Yet, if you put a chair behind them and ask them to sit down, they do a perfect squat.  Why is that?  In the first movement, the individual has to process what you are saying, create a motor plan (in the primary motor cortex), perform the movement, get feedback (via proprioceptors and mechanoreceptors) compare the actual to intended (via cerebellum) adjust (create new motor plan in primary motor cortex) and execute.  That is a lot of thought process.  When we put a chair behind the athlete and have them sit down, this becomes more reflexive in nature which is primarily a spinal driven (via central pattern generator).  What we are trying to assess is the athlete’s natural motion or reflexive motion.  To do this, it requires less higher center input.  So how do we do that?
Simple, don’t talk too much.  Whenever movement assessment you do, you will get more of a reflexive motion if you keep your verbal instruction to a minimum.  The easiest way to do this is demonstration.  Now, giving visual demonstration can influence an athlete’s motion but not near the same degree as if you give instruction.  What is another way that people influence an athlete’s natural motion?  Facial expression.  I will guarantee you, if you have not thought about it, then you are not controlling it and somehow influencing their natural motion.  Take the following example.  Let’s say you are doing a movement assessment on the following female DI athlete.  Every time she steps up on the step, you make the following face.  What is going to be the response of the athlete?  They will either stop and ask you “What?”.  Or they will make adjustments to their movement based on your expression.  Now this is an over dramatized point, but you get the idea because it does happen and it will influence natural motion. 
We called this post, you talk too much for another reason.  If you are doing movement assessment on a young high school freshman versus a movement assessment on an elite DI athlete, there is a psychology that you must overcome with the athlete.  This is especially true when you are pointing out deficits in their motion that leads to potential injury risk and performance issues.  If you are saying I see this or I see that there is an automatic arrogance that you have to overcome in most athletes.  The higher the level of the athlete you are dealing with the more likely you are to deal with it.  In their mind, they are saying, yeah right do you know who I am and who are you to tell me I have this or I have that.  As we all know, it is vital that we build confidence in the athlete!  Without that, compliance with what we ask them to do is greatly reduce and hence the outcome will be less than desirable.  So how do you overcome this?
Simple, video.  When you provide video of an athlete and specifically video of their worst movement, you are not saying I see this or I see that you simply say….This is how you move.  So, whether it is an elite athlete, the star athlete or just a young athlete, for them visually seeing how they are moving gives you instant credibility and them instant buy in to what you are telling them.  That said, a word of caution.  NEVER underestimate the psychological impact that the visual presentation of their movement to them can have on them.  It can be devastating so exercise caution!
We hope that you found this blog insightful and useful.  Next week we will discuss how you integrate the fatigue literature into correcting a lateral shift.  As we stated previously, stay tuned and if you like what you see, SHARE THE PASSION!  It is the biggest compliment you can give.  Follow us on Twitter @ACL_prevention and tweet about it.  #ACLPlayItSafe and help us spread the passion.

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >5000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training. 




Does Concussion Increase Your Risk For ACL Injury - Part IV

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

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

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

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

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

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

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

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




Does Concussion Increase Your Risk For ACL Injury - Part III

In last week's blog, we started looking at the impact concussion has on performance and we posed the question, is there an impact on injury risk?  Logically we would say yes, but what does the research say?

In 2016, Brooks et al looked at the impact that previous history of concussion had on lower extremity musculoskeletal injuries in collegiate athletes.  In this study, the authors looked at athletes from various sports (football, soccer, hockey, volleyball, wrestling, etc) over a 3 year period from one institution.  The concussed athletes were compared to matched controls from the same sport and each were evaluated for lower extremity lower kinetic chain injuries.  What the others found was that concussed athletes were 2.48 times higher risk of lower kinetic chain injury up to 90 days after the athlete was returned to play.  However, according to this study, this became less of a risk factor as time wore on.

However, later in 2016, Gilbert et al published a paper looking at the impact that concussion had on lower extremity injuries in Division I athletes.  In this study, they looked at 335 athletes across 13 different sports and followed them for 4 years.  In literature, a P value <.05 is considered statistically significant and a strong correlation.  In this study, concussion had a strong correlation to ankle injuries (p = .012) knee injuries (p = .002) and lower extremity injuries (p = .031).


This study concluded that Division I athletes with a history of concussion are at 1.6 to 2.9 times greater risk of suffering a lower kinetic chain injury at ANY POINT throughout their Division I career.  Again, this goes right along with what we hypothesized.  That athletes with a previous history of concussion would be at greater risk of ACL injuries due to the poor performance on single limb testing.  Although this paper did not highlight concussion, it did show a high correlation to knee injuries.  According to Myers et al 2012 paper on objective return to play criteria, the authors found that single limb performance was one of the best indicators of risk in sport, especially for ACL risk. Again, considering what we learned about COM displacement, it would make sense that single limb performance would be off and hence indicate the athlete is at higher risk.

Keep in mind again, these are Division I athletes.  So based on what we know physiologically and from the research, our adolescent athletes are at even greater risk.  What does this mean?  Do we just give up and not have athletes participate in sports?  No, absolutely not.  What it tells me is:
  • We need to have better preventative techniques
  • We need to have better rehabilitation and return to play criteria 
Next week, we are going to look at what the research tells us about training and how we can help to reduce the potential for these kinds of injuries and what we should be including in our rehabilitation for safer return to play.  #ResearchThatWorks #ACLPlayItSafe

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




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