Monday, June 18, 2018

Assessing Risk - Is it possible Part VI

Last week, we discussed, according to the research, what we need to assess as well as the importance of video.  We now know that video is an important component of an assessment as well as helping an athlete correct faulty movement patterns. 

In addition, providing video feedback, we also need to look at additional factors that result in compensatory strategies that were identified in the Wren et al study.  Hartigan et al J Ortho Sport Phy Ther 2013 looked at Kinesiophobia (fear of movement) prevalence in ACLR athletes.  What the authors found was that a lot of athletes scored high on the Tampa Scale for Kinesiophobia following ACLR.  This is a research based valid measure of fear of movement in athletes.  Whether it is the chicken before the egg or egg before the chicken, what we do know is that athletes high high Kinesiophobia move differently.  They are more hesitant to move to the involved side, tend to shift their weight away from the involved side and have less control of the limb in single limb activities.  So is it the subconscious awareness of the movement or lack of stability that creates the fear or is it the fear that creates the lack of stability.   Sadly there are a lot of athletes that are discharged from PT who still demonstrate a lot of kinesiophobia.

The answer is not real clear.  What we do know is that you can train them out of it.  Before I knew what kinesiophobia was, the young athlete pictured here presented to my office for a return to play (RTPlay) assessment.  During his history he stated:

  1. I am not confident moving to that side
  2. That side does not feel the same
  3. I don't feel like I am as strong on that side
  4. I am nervous cutting to that side.
These are all classic signs of kinesiophobia.  But what we found during the exam was this same athlete demonstrated one of the largest lateral shifts I have seen (>3 inches away from the operative side) during a squat.  In addition, his single limb test demonstrated a lack of control of valgus in loading and landing as well as a significant variance in vertical hop on the involved versus the non-involved.  So was it his lack of stability and motion causing the kinesiophobia or the kinesiophobia causing the motion.  Most likely it is a combination of the two but both which can be addressed.

What we know is that this starts with providing the athlete with Sport Locus of Control in the visit #1.  Ardern et al Am J Sports Med 2013 showed that athletes who have had an ACLR have relinquished this sport locus of control to the health care provider.  So what the heck is that and why does it matter?    As an athlete, who is in control of your destiny as an athlete?  Who controls how hard you work?  Who determines how hard you practice?  Who determines how much you effort you put out on the field.  Ultimately, who determines you success in sports?  The answer in most cases is you, the athlete.  You are in control of your destiny.  You have the sport locus of control.  You are in control of your destiny in sports.

Following an injury or ACLR, the athlete, many times for the first time, reliquish this sport locus of control to the health care provider.  So suddenly someone else tells them what they can do at the gym, when they get off crutches, when they can start doing drills, practice with or without a brace and when they can get back to sport.  In other words, someone else has the Sport Locus of Control.  This lack of control can lead to depression and can add to kinesiophobia.  So, it is vital that we give that control to the patient in visit 1.  I am often heard saying, I am simply a coach and an educator, I will coach you along the process and educate you why we do what we do but at the END OF THE DAY IT IS UP TO YOU!  In that one sentence, I am passing the sport locus of control over to the athlete.

In addition to passing the sport locus of control onto the athlete, we must also think through how we can impact kinesiophobia starting immediately in the first visit.  What we have found that works very well is:

  1. Educate the athlete why you do what you do - they are much more likely to do if they know why.
  2. Pair with other ACLRs who are later in the process.  This will create conversations and they will see how far along they will be in 3 weeks, 2 months, 4 months - it is encouraging.
  3. Start full weight bearing as soon as possible.  This will help to normalize gait, aid in reducing qua atrophy and reduce risk for lack of TKE with gait.
  4. Start single leg activities as soon as possible.  This is NOT balance but things like single leg squats, single leg hops, etc.  This will build confidence.  
  5. Push quality over quantity.  We know it is the magnitude and speed of valgus that cause injury.  Make sure they control that throughout the range of motion prior to proceeding.  
  6. Make them work hard.  Push them hard but safely.  People are often amazed at what they can achieve.  
Take a look at this still taken from an Olympic athlete that had been dealing with an injury.  She was reporting loss of confidence on this side as well as loss of explosive power.  Despite months of rehab and working with sprint coaches, and strength coaches, these movements remained.  By providing her visual feedback (via video), educating her on, giving her the control training her hard to prevent, not only is she able to run pain free but also is performing at a higher level.

Too touchy for you?  Me to.  Next week we will talk about specific training to control dynamic valgus.  Please make sure to check out our new website at www.iceperform.com where our goal is to help you help others.  #ViPerformAMI



Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the founder | developer of the ViPerform AMI, the ACL Play It Safe Program, Run Safe Program and author of a college textbook on this subject.  Trent has performed >5000 athletic movement assessments in the US and abroad.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Vice Chairman of Medical Services for USA Obstacle Racing and movement consultant for numerous colleges and professional teams.  Trent is also a competitive athlete in Brazilian Jiu Jitsu. 

Monday, June 11, 2018

Assessing Risk - Is It Possible Part V

During the last couple of weeks, we looked at a recent study published by Wren et al J Orth Sports Phy Ther 2018.  In this study the authors looked at hop distance symmetry as a predictor of lower limb biomechanics.  The authors found hop distance is not a predictor of biomechanics and that the athletes tend to compensate on the non-involved leg.  As we began our discussion we talked about how this happens in our athletes and what we must do to prevent.

Last week, we began discussing mental compensation (kinesiophobia) and lack of training as a potential cause for this being a pattern that athletes continue with even when they return to play or post rehabilitation.  It is suspected or hypothesized this could be one reason that athletes continue to be at greater risk of re-injury (Wiggins et al Am J Sports Med 2016) or osteoarthritis 12 years later (Holm et al Am J Sports Med 2012).  As a physical therapist, athletic trainer or strength coach, there is a lot that we can do to change these odds.  First, we have to know what to look for.

In our last series, we discuss the Johnson et al Am J Sports Med 2018 paper where the authors identified the mechanism for non-contact ACL injuries in professional football players.  This led the authors to suggest there was a need to develop programs that assess and assist athletes to control this dynamic valgus position.  Although this is relevant for NFL players, is this also relevant for our younger college and high school players?  Owusu_Akyaw et al Am J Sports Med 2018 looked at the mechanism of injury in male and female athletes ranging from 15-30 years old.  Although the authors did not have video analysis available for all injuries, they were able to identified the position of the articular surfaces at the time of the injury by evaluating the bone bruising that was present on the surfaces.  Based on biomechanical models, this reveals a similar dynamic valgus position at the time of injury.



Considering, we must then assess this.  There are a lot of ways to do this.  You can do with a variety of movements and variety of technologies.  For our athletes, we use the ViPerform AMI (powered by DorsaVi) due to the fact that it has a progressive routine of single limb tests.  This assesses the ability to stabilize in single limb and it is measured with an inertial measurement unit and video.  The IMU provides accuracy of measurement within 3% of a Viacom system and the video provides a medium for providing feedback to the athlete.


As we mentioned in the previous blog, assessing both the magnitude of motion and speed of motion is critical when looking at risk.  Keep in mind, the ACL is about the size of your pinky.  It takes 21.5 N of torque (rotation) to rupture and 250 kg of force.  In a closed kinetic chain, the more valgus that occurs at your knee the more torque that is imparted to the ACL (with larger degrees of valgus comes internal rotation in a closed kinetic chain).  In addition, force is determined by both the amount of motion that occurs and the speed at which that motion occurs.  Therefore, assessing only the amount of motion is only half the picture, you must also look at the athlete's ability to control the speed at which that motion occurs.  With IMUs, you can capture not only the amount of motion that occurs but also the speed at which that motion occurs.

Why is video feedback so important?  Agresta et al J Ortho Sport Phy Ther 2015 performed a systematic literature review looking at common movement patterns present in runners that predisposed to injury and effective ways at which change that.  What this study found was that providing video feedback helped the athlete make immediate changes to their running patterns.  What we have found is that video helps in several ways:


  1. Showing an athlete how they move on video is a very effective tool to helping them understand the complexity of and relation to impact on sport
  2. Showing them a video of them moving has an immediate impact on their buy in to what you are telling them and their overall compliance.  

So, this was a really long way around approaching how we can use this in our training.  Providing video feedback is critical first step in training the athlete.  It starts with the assessment.  Showing the athlete how they move during single limb performance and during fatigued state.  This will assist in the immediate buy in and help the develop a better kinetic sense of the movement.   In addition, this will also assist in further training down the road when we are cuing them on correctives.  They will be able to correct the movement faster without the need for external visual input since they got this earlier in the rehabilitation or training routine.

Next week, we will continue our discussion on use of video in our assessment as well as how to address athletes subconsciously avoiding that involved side.  Please make sure to check out our new website at www.iceperform.com where our goal is to help you help others.  #ViPerformAMI


Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the founder | developer of the ViPerform AMI, the ACL Play It Safe Program, Run Safe Program and author of a college textbook on this subject.  Trent has performed >5000 athletic movement assessments in the US and abroad.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Vice Chairman of Medical Services for USA Obstacle Racing and movement consultant for numerous colleges and professional teams.  Trent is also a competitive athlete in Brazilian Jiu Jitsu. 

Monday, June 4, 2018

Assessing Risk - Is It Possible Part IV

Last week, we looked at a recent study published by Wren et al J Orth Sports Phy Ther 2018.  

Hop Distance Symmetry Does Not Indicate Normal Landing Biomechanics in Adolescent Athletes with Recent Anterior Cruciate Ligament Reconstruction. 


The following conclusions came out of this study.  Both symmetric and asymmetric patients offloaded the operative knee and symmetric patients achieved symmetry in part by hopping a shorter distance on the contralateral side.  Therefore, hop distance symmetry may not be an adequate test of single limb function and return to sport readiness.

Discussion:  Let's take a little further look at the results.  The first result, asymmetrical patients did not jump as far on the operative side, is expected.  If an athlete has asymmetry in this test (which is a measure of distance jumped on the operative leg compared to the contralateral side), then hopped shorter distance on their operative limb and are therefore asymmetrical.  That is why, in this test, they would be asymmetric in the first place.  So no big revelation there.  

The other result, symmetric patients achieved symmetry in part by hopping a shorter distance on the contralateral side.  This test is designed to be a way to assess limb symmetry index or the variance between the right side and the left side.  Studies have shown (Rhoman et al Am J Sports Med 2015) that norms have a limb symmetry index of 85%.  Considering this, it is hypothesized if an athlete has a variance >15% on the right versus the left, then they are at greater risk of injury.  Based on the results here, we can make the assumption that this test will not show us who is at risk.  Whether consciously or unconsciously, the athlete is modifying effort on the non-involved limb which will misrepresent the true limb symmetry index. 

However, the area of biggest focus for most of us is what are the biomechanics at take-off and landing?  As the athlete is going into loading the limb for explosive power and begins to explode up, it is usually the transition from loading the limb to explosive movement that you will see the knee move into the dynamic valgus position.  This is a focus for most as we know that this motion is the one that will or could potentially lead to increase risk for ACL injury or mensical injury. 


If you take the above slide as an example, you will see that based on basic biomechanics that force is determined by both the magnitude of the motion (how much the knee moves into valgus) and speed (how fast it moves into valgus) at which that motion occurs.  So the larger the valgus is at loading and the faster that valgus occurs at loading, the greater the risk is that force will be departed to the ACL and the meniscus.  This is something we want to measure and quantify.  According to Johnston et al Am J Sports Med 2018, based on video review of non-contact ACL injuries in football players, dynamic valgus is the position that causes ACL rupture which led the authors to suggest this should be something that is assessed to identify those at risk. 

This same motion is typically observed again at landing.  When the athlete’s foot contacts the ground and they have to being to attenuate the force through the foot/ankle, knee and hip.  It is typically at this point under high loads that you will again observe the knee move into the dynamic valgus position. Considering the ground reaction forces generated in landing (on a basketball court) is anywhere from 4-8 times body weight, we can understand the importance of controlling this motion during these movements.

This study also showed there was lower knee flexion moments and subsequent decrease in energy attenuation along the system.  We see this a lot in athletes following an ACLR and think a lot of this has to do with mental compensation and lack of training. 

First let’s look at mental compensation leading to lower knee flexion moments.  What we suspect in these cases is the athlete subconsciously knows they lack the control of the knee to prevent dynamic valgus at larger knee flexion angles.  This is a position that gives them a lot of fear (kinesiophobia - fear of movement) since they subconsciously know this is the position during which they tore their ACL.  As a result of the fear, they will subconsciously compensate and not allow themselves to fall into larger knee flexion angles because they loose control.  If they allow greater flexion angles during the landing phase then they will fall into this dynamic valgus motion and potentially rupture their ACL.  If this is not addressed (through out their rehab and return to play) then this adds to greater ground reaction forces being distributed to the knee, hip and low back.  This will break down tissue and potentially result in additional non-contact injuries.  In addition to this, it can also add to a lack of force production.  Most will demonstrate both in landing and take-off.  In take-off, by decreasing flexion angles, this results in a decrease in force production and power output.

Next week, we will look at the lack of training and how this leads to decreased knee flexion angles.  Please make sure to check out our new website at www.iceperform.com where our goal is to help you help others.  #ViPerformAMI



Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the founder | developer of the ViPerform AMI, the ACL Play It Safe Program, Run Safe Program and author of a college textbook on this subject.  Trent has performed >5000 athletic movement assessments in the US and abroad.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Vice Chairman of Medical Services for USA Obstacle Racing and movement consultant for numerous colleges and professional teams.  Trent is also a competitive athlete in Brazilian Jiu Jitsu. 

Monday, May 28, 2018

Assessing Risk – Is It Possible Part III

Last week, we began to look at some of the common ways we assess for injury risk in pre-season physicals and for making return to play decisions for our athletes.  One of those tests we described was the single leg hop test for distance.  In this test, the athlete performs a maximal jump for distance on one leg and the distance is measured.  The hypothesis is that if this is within 85%-90% that the athlete is at less risk and they are able to return to play.

The single leg hop test is just one test of several that are used for making this determination.  Another test is the triple hop for distance.  This is essentially the same test except three hops are performed instead of one.  Based on the work of Johnston et al 2018 and Owusu-Akyaw et al 2018, both suggest that the mechanism of injury is dynamic valgus.  The question becomes, do these test measure these at risk motions?

Last week, we mentioned what we see anecdotally in the clinic but is this what is reflected in the literature.  What we see in the clinic is an athlete can have symmetry in these types of test regardless of biomechanics.  They may be able to perform the test within symmetry but perform the test with horrible biomechanics.    As demonstrated here with this athlete, we see that when they land they demonstrate the dynamic valgus that was mentioned in the previous studies that we need to assess for.  But if we went solely by the criteria for the hop tests, then this athlete would have been returned to play.

Considering this, we can look at a recent study published by Wren et al J Orth Sports Phy Ther 2018. 

Hop Distance Symmetry Does Not Indicate Normal Landing Biomechanics in Adolescent Athletes with Recent Anterior Cruciate Ligament Reconstruction. 

Background: Return to play following anterior cruciate ligament reconstruction often includes functional assessments such as hop for distance symmetry and triple hop for distance symmetry.  It is unclear if symmetry in these tests indicate if there is any movement deficits present that may put the athlete at risk for non-contact injuries. 

Purpose: The purpose of this study is to assess the biomechanics and symmetry of adolescent athletes following anterior cruciate ligament reconstruction (ACLR) during a single leg hop for distance test.

Methods: Forty six patients with ACLR (5-12 months post-surgical) performed the single leg hop for distance test.  A comparison of the participant demographic and clinical characteristics among groups is represented in Table 1.  During the single leg hop trials, three dimensional motion analysis data was also collected via an 8-10 camera motion capture system (Viacom).



Each participant was classified as asymmetric (operative limb hop distance <90% of non-operative limb; N=17) or symmetric (N=29).  Lower limb biomechanics were compared among operative and contralateral limbs and the 24 symmetrical controls.

Results: Compared to controls, asymmetric patients hopped a shorter distance on their operative limb (P<0.001), while symmetrical patients hopped an intermediate distance on both sides (P≥0.12).  During landing, operative limbs, regardless of hop distance, exhibited lower knee flexion moments compared to controls and the contralateral side (P≤ 0.04) with lower knee energy absorption than the contralateral side (P ≤ 0.006).


During take-off, both symmetrical and asymmetric patients had less hip extension and smaller ankle range of motion on the operative side compared to controls (P≤ 0.05).  Asymmetric patients also had lower hip range of motion on the operative, compared with the contralateral side (P =0.001).

Conclusion:  Both symmetric and asymmetric patients offloaded the operative knee, symmetric patients achieved symmetry in part by hopping a shorter distance on the contralateral side.  Therefore, hop distance symmetry may not be an adequate test of single limb function and return to sport readiness.

Next week, we will begin our discussion on how we may interpret these results and what some of the take aways are.  Stay tuned and please make sure to check out our new website at www.iceperform.com where our goal is to help you help others.  #ViPerformAMI


Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the founder | developer of the ViPerform AMI, the ACL Play It Safe Program, Run Safe Program and author of a college textbook on this subject.  Trent has performed >5000 athletic movement assessments in the US and abroad.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Vice Chairman of Medical Services for USA Obstacle Racing and movement consultant for numerous colleges and professional teams.  Trent is also a competitive athlete in Brazilian Jiu Jitsu. 

Monday, May 21, 2018

Assessing Risk - Is It Possible: Part II

From our last series, we know that previous knee injury does impact future performance.  During that discussion, we highlighted a study by Johnston et al that looked at the position of the lower kinetic chain at the time of injury.  This study was done via video analysis of footage of NFL game and practices during the time of the athlete's ACL injury.  We know from this study that non-contact ACL injuries occur when the limb is place in a position of dynamic valgus and under high loads (shifting position).

Last week we began the discussion to see if this is the position just for professional players or do younger athletes also present with a similar position during non-contact ACL injuries.  For this discussion we looked at recent study by Owusu-Akyaw et al which analyzed bone bruise patterns in younger athletes.  Based on these results, the dynamic valgus position (flexion, valgus and internal rotation) is a position that results in ACL rupture in male and female athletes under high loads.  Based on the results of both of these studies, then it would make sense that we must find ways to assess this in our athletes.  To do so, we should look at the literature and see what is currently being used to assess athletes for risk.

One test that is being used to assess athletes for risk is the single leg hop test for distance.  During this test, the athlete stands on the leg to be tested.  They will then hop as far as possible and land on the same limb.  This is repeated on the contralateral limb.  This is typically performed three times and the distance is measured for each.  Using the average of the three, the assessor is looking for limb symmetry (being equal on both sides) within 85%-90%.  The assumption is that if limb symmetry is achieved that the athlete is not at risk.  This is a common tool that is being used to assess risk in pre-participation physicals and for return to play following ACLR.


In 2015, Rohman et al published a paper in the Am J Sport Med looking at limb symmetry in athletics.  What they found was that 93% of norms had limb symmetry greater than or equal to 85%.  So if norms have 85% limb symmetry, what should be the number for those at risk.  Most physicians will use 85%-90% of the contralateral limb.  Considering this study however makes us question if an athlete is at 85% are they really at risk?  I am not sure if we know the answer to this question but it is something we need to consider when making these kinds of calls with the above mentioned test.  

For demonstration purposes, let's suppose the athlete has 95% limb symmetry on the single leg hop for distance test.  Is this athlete at risk or are they ready to return to play.  If we only consider the above information, we might say yes.  According to the Johnston et al study and the Owusu-Akyaw et al previously mentioned, we need to measure dynamic valgus to assess risk as these are the movements that rupture the ACL under athletic types conditions.  If an athlete is demonstrating 95% limb symmetry on this test, is this indicative that these movement patterns are not occurring?

Or, could an athlete perform this test and be 95% symmetrical and still demonstrate the movement patterns shown here.  The assumption is that with all of the hop tests (single leg hop for distance, triple hop for distance and lateral hop) that symmetry = good biomechanics.  But is this the case?  What we see anecdotally is this is not the case.

This is what we see but what does the literature tell us.  Next week we will look into this.  Make sure to stay tuned.  Please make sure to check out our new website at www.iceperform.com where our goal is to help you help others.  #ViPerformAMI


Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the founder | developer of the ViPerform AMI, the ACL Play It Safe Program, Run Safe Program and author of a college textbook on this subject.  Trent has performed >5000 athletic movement assessments in the US and abroad.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Vice Chairman of Medical Services for USA Obstacle Racing and movement consultant for numerous colleges and professional teams.  Trent is also a competitive athlete in Brazilian Jiu Jitsu. 

Monday, May 14, 2018

Assessing Risk - Is It Possible?

Over the course of the last blog series, we discussed whether previous knee injury impacts future athletic performance.  There was compelling evidence presented throughout this series that previous injury not only has an impact on future performance but also health care costs.  The Mia et al study in 2017 made it pretty clear, that at least in NFL football players, there was a big impact on performance up to 2 years post ACLR and professional players' careers were decreased by 2 years. 

In this series, we also discussed in this study what is the most common mechanism for an ACL injury in football.  In the Johnston et al study in 2018, the authors found that a majority of ACL injuries in the NFL are non-contact in orientation and that the limb is in a position of dynamic valgus (as seen here).  These results led the authors to suggest that there should be some targeted programs designed to assess and control valgus. 

Although it is great to work with professional athletes, the majority of us don't get that opportunity and therefore the majority of our population is youth athletics.  Frankly, these are the ones that should have our major attention, especially when it comes to injury prevention.  This last weekend at the Andrews Institute's Annual Injuries in Football Course, Dr. John Polousky presented on the youth ACL epidemic.  He stated there are some 45 million kids that participate in organized athletics and roughly 50% of all sports related injuries are due to overuse.  Current literature shows that 1 in 4 elementary and middle school aged kids suffer an ACL injury at some point in their athletic career accounting for ~200,000 ACL injuries in youth athletics.

As a parent and health care provider, this is unacceptable!  We have to do something about it and if we don't we are adding to the problem through our own negligence.  According to the Johnston study cited above, we know movements that put the athlete at risk for non-contact ACL injuries, at least in professional players.  But does that apply to youth athletics? 

That will be the first thing we will look at in this series.  We will start off this discussion by looking at a recent study by Owusu-Akyaw et al in the American Journal of Sports Medicine 2018. 

Determination of the Position of the Knee at the Time of an Anterior Cruciate Ligament Rupture for Male Versus Female Patients by an Analysis of Bone Bruises

Background: Female athletes rupture their ACL at a rate 2 to 4 times higher than their male counterparts.  As such, several studies have looked if males and females sustain ACL injuries vai different mechanisms.  By understanding the mechanism, we can then create assessment tools and injury prevention programs to address. 

Hypothesis: Compare the knee position at the time of the non-contact ACL injury between the sexes.  It is the hypothesis of the authors that there will be no differences in the position during injury. 

Methods: T2 MRI scans were retrospectively reviewed for 30 athletes (15 male and 15 female) who sustained non-contact ACL ruptures.  MRIs were performed within one month of the initial injury.  All participants had contusions associated with the ACL injury on both the medial and lateral articular surfaces of the femur and tibia.  3D models of the femur, tibia and bone bruises were created via segmentation on MRI (pictured to the right).  The femur was positioned relative to the tibia to maximize bone bruise overlap, thereby predicting the bone positions near the time of injury.  Flexion, valgus, internal tibial rotation and anterior tibial translation were measured in the predicted position of injury.

Results | Conclusion: There is no statically significant difference between male and female knee positions during the time of ACL injury.  The results suggest a similar mechanism of injury for both the male and female athlete. 

Obviously this is a very novel approach to determining knee position during a non-contact ACL injury.  In most settings, video review would be the gold standard as you get to see actual footage of the limb position at the time of the injury.  In professional sports this is great and with the amount of videoing that is occurring in practice and game time, you can be pretty much assured this will be captured.  However, in youth athletics, it is rare that video footage exist where the the mechanism of injury is captured.  As such, this novel approach could provide some great insight as to the limb position during injury. 

Although this is based on solid biomechanics, it still is not the gold standard.  As such, there are some other factors that may impact this.  For example, we are basing this off the assumption that the bone bruise occurred at the time of the injury.  But, what if the bone bruise did not occur at the time of the injury.  What if the athlete continued to play and that resulted in the subsequent bone bruise?  This would then provide a false reading and led to a misinterpretation of the limb position at the time of the injury. 

This has to be considered but in reality it is most likely that the bone bruise did occur at the time of the initial injury.  The mechanism of injury (flexion, valgus and internal rotation), is very similar to what other studies have reported and what the previous Johnston study reported on video review of non-contact ACL injuries.  Based on the results of these studies, as well as numerous others, it is clear we need to assess the ability to control dynamic valgus at the knee.  Not only do we need to assess that but we need to:

  • Assess ability to control during single limb performance
  • Assess ability to control during multidirectional tasks
  • Assess ability to control both the motion and speed at which that motion occurs
Next week, we will look at some current methods we are using to assess this for determining return to play of athletes and see if this has the ability for use in determining risk in pre-seasons physicals.  Please make sure to check out our new website at www.iceperform.com where our goal is to help you help others.  #ViPerformAMI



Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the founder | developer of the ViPerform AMI, the ACL Play It Safe Program, Run Safe Program and author of a college textbook on this subject.  Trent has performed >5000 athletic movement assessments in the US and abroad.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Vice Chairman of Medical Services for USA Obstacle Racing and movement consultant for numerous colleges and professional teams.  Trent is also a competitive athlete in Brazilian Jiu Jitsu. 


Monday, May 7, 2018

Does Previous Knee Injury Impact Performance & What Can We Do About It? - Part V


Over the course of the last several weeks, we have been looking at the impact that previous knee injury has on future performance.  Knowing that previous knee injury does impact performance this led us along the logical progression of how do we assess this risk factor and more importantly is there anything we can do about it.  The Johnson et al study guided us on what we should be assessing and the Lopes et al study let us know that we can change these biomechanical factors with the right program. 

Knowing that we can impact injury rates with the right program and that we are assessing athletes for ability to stabilize their lower kinetic chain in frontal plane, it would make sense that programs that focus and train these principles would be more effective.  That led us to the Omi et al Am J Sport Med2018 study.



Effect of Hip-Focused Injury Prevention Training for Anterior Cruciate Ligament Injury Reduction in Female Basketball Players: A 12-Year Prospective Intervention Study.

Purpose: The purpose of this study was to determine the effectiveness of hip focused ACL injury prevention program in female basketball players.

Methods:  This was a prospective intervention study conducted for 12 years.  During the 4 year observation period, incident rates of ACL injuries were collected from female college basketball players.  Following the observation period, a hip focused ACL injury prevention program was implemented for 8 years (the intervention period).  A total of 309 players (age 19.6 years ± 1.2 years, height 163.7 cm ± 5.6 cm, weight 59.1 kg ± 5.1 kg) were tracked and compared with 448 players (age 19.6 years ± 1.1 years, height 162.6 cm ± 5.8 cm, weight 58.0 kg ± 5.7 kg) who participated in the intervention period.  Athletic exposures, ACL numbers and mechanisms of injury, relative risk and absolute risk reduction, numbers need to treat and compliance were analyzed.
Results:

ACL Injuries during the 4 year observation period
  • 16 ACL injuries
  • 13 of which were non-contact in orientation (81.3%)
  • Avg. 4 ACLs/year
  • Incident rate = .25/1000 AEs



ACL injuries during the 8 year intervention period
  • 9 ACL Injuries
  • 8 of which were non-contact in orientation (88.9%)
  • Avg. 1.1 ACL/year
  • Incident rate = .10/1000 AEs



Discussion:  The hip focused injury prevention program demonstrated significant reduction in the incidence of ACL injury in female collegiate basketball players.  This particular program has a significant focus on hip strengthening and single limb performance.  In addition, there is a fair amount of focus placed on technique and control of the knee in the frontal plane. 

Considering the Lopes et al study and the Omi et al study, one might conclude that assessing an athlete prior to performance of a program like this would not only allow us to measure the pre/post impact to the intervention but also may assist us in progressing an athlete through the series of the exercises to a higher level once stability in the frontal plane is obtained. 

So now that we know what to do about it, we now have some ways we can assess and based on that assessment drive a corrective program.  The final question we need to look at is what we do with those athletes who have had an injury.  Is there anything we can do to help them return to play without increasing risk for reinjure and reducing the impact there is on performance?  To close out this series next week, we will look at the Wren et al study looking at hop test and whether or not this this a good test for return to play.  Next week we will look at the Wren et al J Orth Sport Phy Ther 2018 study.


Also, please make sure to check out our new website at www.iceperform.com where our goal is to help you help others.  #ViPerformAMI


Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the founder | developer of the ViPerform AMI, the ACL Play It Safe Program, Run Safe Program and author of a college textbook on this subject.  Trent has performed >5000 athletic movement assessments in the US and abroad.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Vice Chairman of Medical Services for USA Obstacle Racing and movement consultant for numerous colleges and professional teams.  Trent is also a competitive athlete in Brazilian Jiu Jitsu.