Monday, June 19, 2017

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. 


Monday, June 12, 2017

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 2nd surgery 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 Medicine in 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 al published 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. 


Monday, June 5, 2017

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 al published 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. 


Monday, May 29, 2017

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. 


Thursday, May 25, 2017

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. 



Monday, May 15, 2017

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. 



Monday, May 8, 2017

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.