Monday, January 16, 2017

Innovations in Movement - Blending Movement Science with Technology - Part III

Last week, we discussed various technologies that could be leveraged clinically to assist us in assessing human movement.  During last week's post, we looked at apps, 2D technologies and 3D technologies that could assist us in efficiently and reliably assessing human movement.  With the advent of technology, simply relying on the human eye has been shown to be less efficient, less accurate and less reliable.  As such, we can now leverage technologies to do what we use to through simple observation.  This provides us much more accurate and objective measures of progress and current status.

As we continue this series, we now want to start investigating what technological advancements has there been that can aid us in the treatment of human movement.  Keep in mind, throughout this discussion, the goal is not to simply use the snazziest advancement on the market but more importantly to incorporate technologies that can allow us to efficiently and reliably correct movement dysfunction and which can be easily implemented with the lowest cost barrier to entry.  To use technology that leverages the latest in movement science with the latest advancements in movement technology.  That said, we will approach this section from four perspectives.
  • 2D video
  • Biofeedback
  • Resistance bands & product innovations
  • Tracking & compliance
2D Video:

2D video provides us a great tool to provide visual feedback to the athlete.  When assessing high level athletes, some are very receptive to your interpretation of movement and some are not as receptive, especially if they are a high level athlete (or they perceive themselves as high level athlete).  Therefore, the ability to show the athlete how they move is instrumental part of getting the athlete's psychological buy in to what you are trying to achieve.  Video based software and apps allow us a medium which we can not just describe the movement we see, but actually show the athlete the motion.  From this visual feedback, we can then help them make corrections in, correlate that movement to injury risk and how that movement impacts athletic performance.

One of the most widely used video technologies is Dartfish.  This technology offers a lot of advantages for assessing movement and for treating movement.  In a systematic review by Agresta et al - J Orth Sport Phy Ther 2015 the authors showed that video feedback provided to runners by using real time feedback (via Dartfish) during their run was very effective tool at helping runners address their running movement dysfunctions.  Dartfish is one of the few technologies that allows you the ability to do live video feedback that can be used during live training with an athlete and is extremely helpful in helping them correct their movement dysfunction.   

In addition to 2D video software based technologies, there are also several apps that are offered out there that can be used to provide video feedback.  One major limitation of all of these is the inability to do live feed to a television or projector.  Where Dartfish allows the athlete to see this live, correct as they go and see the immediate results, most Apps do not allow.  With Apps, this information is recorded and then provided to the athlete after the fact.  Therefore the ability to correct that movement on the fly is not easily obtained.  Although providing feedback after and then having them correct still works, the training impact is more immediate with live feed.  

Some of the most common Apps are listed below and have the ability to function on IOS and Android.  

  1. Hudl - this is a 2D app that offers some versions for free and some upgraded versions offered at minimal cost.  This app allows you to capture movement and perform slow motion.  This allows you to show the athlete motions which occur at a high rate of speed at a speed which they can see.  
  2. Dartfish Express - this comes to us from Dartfish and includes some of the capabilities that
    are available in the software.  It allows some of the same functionality of the others but the quality and functionality of this app seems to have a step ahead.  It is available for minimal cost.  Videos can also be saved to Dartfish TV which you can then give access to the athlete to see and download in media books.
  3. Coaches Eye - this is another 2D app that initially started as a tool for coaches to assess players motion during athletic competition or practice.  The application to the treatment of movement is obvious and it also offers some of the same functionality of the previous two.  
Biofeedback

With advancements in technology, we now have several technologies that can be used for biofeedback.  Some of the most commonly used include:


  • DorsaVi - as mentioned in the previous blog, DorsaVi is a "true" 3D motion analysis system that uses an IMU (inertial measurement unit) to provide 3D data and feedback.  DorsaVi has a module that is available within the system that provides the subject real time feedback on motion. So the athlete will use the sensors during treatment to provide them real time data on where their body is in space and the system will use this to challenge them through a series of tests and exercises.  Although the current application is for balance and lumbar spine, I suspect that lower kinetic chain training will be available in the future.  In addition, there is the ability to attach the sensors to the athlete and have them go for a 1 hour, 2 hour or 4 hour run while collecting data or reporting the data during the live run.  This allows you to make adjustments to their running and see the direct impact on IPA (initial peak acceleration) and ground reaction forces. 




  • Tecnobody Isofree - has a system coming out on the market that uses the XBox One and time of flight technology combined with a force plate to provide feedback of joint position and weight distribution.  This is a great tool for providing proprioceptive retraining for the athlete.  With this device, the athlete stands on the device and the system tracks their body in space while taking them through a series of challenging, fun and interactive games.  Although there is nothing on the website about, based on their other systems, I suspect this will be in the $20K range.


  • Motion Guidance - this is a relatively simple and inexpensive device that was developed by two physical therapists.  This system uses a small laser strapped to the lower extremity and target.  This is a great tool for use in jump training and while performing single leg activities that will provide instantaneous feedback to the athlete if they are able to maintain stability of the knee in the frontal plane as well as pelvic stability.  These kits also come with a patient HEP pack that the athlete can take home for their home exercise program.



This is by no means an exhaustive list but more at list of products that we have used and have some familiarity with.  Next week we will continue this discussions as we look at some product innovations which can be used in the the treatment of movement dysfunction.



Dr. Nessler is a practicing physical therapist with over 17 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, January 9, 2017

Innovations in Movement - Blending Movement Science with Technology - Part II

Last week, we started this series to look at how we can leverage what we know in the movement sciences with technology.  The intent of this series is to share with you the various technologies we have encountered as well as some of the benefits and challenges of these.  Considering this, during this series we are going to touch on several different aspects.

  1. Technologies to assess movement
  2. Technologies to treat movement
  3. Training technologies to train proper movement
Last week, we looked at the use of 3D technologies to assess human movement.  This week, we will continue looking at 2D technologies and some specific technologies that are available on the market for doing this.  Before we do that, we should discuss the challenges associated with use of 2D.  These can be mitigated but we must be aware of in order to control.  Remember, we are attempting to make 3D interpretation off a 2D image.  Sometimes that 2D image may appear to show something that is truly not there in a 3D environment.  

Some things to consider when performing movement assessments using 2D technology.


  1. Camera orientation - in order to get a true picture of frontal plane movement of lower kinetic chain, you must have the camera directly infront of the athlete perpendicular to the orientation of the athlete (depicted here).  If the camera orientation is slight off (off to the right or left of the athlete) then this will result in seeing a valgus or varus that is not really there.  If the camera is tilted down or up, then again you will see motion that may not actually be there.  As common knowledge as this sounds, I attend a lot of conferences with some very reputable companies presenting on 2D analysis showing adduction at the knee during a movement and the orientation of the camera to the athlete is way off to the side.  This can all be avoided by ensuring the camera orientation is perpendicular to the athlete.
  2. Angles - most of the 2D technologies out there offer the ability to measure angles.  When measuring human movement, the difference between 5 degrees and 15 degrees can mean the difference between an athlete at risk and one that is not at risk.  What we know is that when you measure angles on 2D, there is an inter and intrarater reliability of +/- 10 degrees.  So, did you really improve that frontal plane motion by 10 degrees or that supination by 5 degrees or did you simply put your starting point at a different spot.  If you are going to use the angle function on these technologies, you can reduce some of this error by palpating the bony landmarks on the athlete, placing markers on those anatomical references and use those when reviewing the video.
  3. Tracking - although this is a really cool capability of some of these technologies, use of tracking with a 2D technology is done via pixels and relies on color.  That being said, if you have an athlete in dark colors against a dark surface, the tracking capabilities will be very limited.  If you are going to use this capability, there must be some significant contrast in colors to have increased accuracy of the tracking.  In addition, the slower the movement is the more accurate the tracking will be.
  4. Stability - this one goes without saying and most control for this.  But attempting to assess movement using 2D video without use of a tripod is very difficult.  This is more common with the use of the smart phone or Ipad for assessing movement.  Again, if not controlled, you will see movement that may not be accurate.  
  5. Frames per second - for any 2D analysis, it is important to know what the fps your camera is.  Optimal is to have a camera with 120 fps or >.  Using cameras with 30-90 fps will result in videos that will be choppy when you are analyzing them in slow motion.  This will often lead to missing the pathological movement you are looking to assess.
For 2D assessment, there is 2 basic types.  Desktop software and Apps.  

Desktop software:

Two of the most common desktop software companies are Dartfish and Kinovea.  Dartfish is a Switzerland based company that was originally used by high performance coaches in professional and Olympic athletics.  Dartfish developed "stromotion" which allowed coaches to see how athletes are moving through all the phases of athletic performance.  This allowed coaches to capture minor nuances throughout the extremely high speed motions in order to create more coachable opportunities.  For me, Dartfish was instrumental in my ability to truly assess and understand movement.  It allowed me to slow down movement to the point that I could capture pathological movement patterns form which I could train athletes to improve and use it to educate them about their movement.  
Although we did not use this to put angles on movement, what we did find is much more accurate way of quantifying frontal plane motion with this technology.  By simply using plumb lines and specific anatomical landmarks, we found that this had a high correlation to frontal plane motion captured via Viacom system.  So we could not only objectively measure frontal plane motion but also objectively quantify improvements in that motion.  

Kinovea is a French based company that offers a 2D video technology that looks and functions very similar to Dartfish.  Although this software is free, it should not be mistaken that there are some fundamental differences in Kinovea and Dartfish.  First off is reliability of the software itself.  There is nothing worse than capturing data on over 30 players and having the system corrupt the videos as you are doing your analysis on later (speaking from experience).  Although some of the functionality is similar, it does not offer the same level of capabilities of Dartfish.  If you are just starting out in movement assessment, this is a good and cheap alternative to start to get your feet wet.  But if you are doing a lot of movement capture, spending the money on Dartfish is money well spent.

Apps:

There are a lot of different apps that are offered out there for assessing human movement and too many to mention them all.  In this section, we will talk about some of the most common ones.  Most have the ability to function on IOS and Android.  

  1. Hudl - this is a 2D app that offers some versions for free and some upgraded versions offered at minimal cost.  This app allows you to capture movement, perform slow motion and draw lines on the video.
  2. Dartfish Express - this comes to us from Dartfish and includes some of the capabilities that are available in the software.  It allows some of the same functionality of the others but the quality and functionality of this app seems to have a step ahead.  It is available for minimal cost.
  3. Coaches Eye - this is another 2D app that initially started as a tool for coaches to assess players motion during athletic competition or practice.  The application to movement assessment is obvious and it also offers some of the same functionality of the previous two.  
This is by no means an all inclusive list but just a list of the ones we have had the most experience with.  We hope you found this helpful and next week, we will be discussing some movement technologies we can use with treatment.  



Dr. Nessler is a practicing physical therapist with over 17 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, January 2, 2017

Innovations in Movement - Blending Movement Science with Technology

Over the course of the last several years, we have talked a lot about movement and the correlation to injury risk and athletic performance. Based on these discussions, I think most would agree that assessing movement as a part of athletics is important.  But how do we do this in a meaningful and reliable fashion.  How do we do in a way that is valid and yet efficient enough that we can use it with a team of 18 volleyball players or 110 football players?  This is where we need to look at various technologies and then blend those with what we know from the movement sciences.  We will preface this series with the fact that I am not an IT specialist nor do I pretend to know all the ins/outs of technology.  However, I have used technology for >10 years to assess and treat movement dysfunction.  So although I am not an expert in this area, I have some proficiency with the use of in athletics and had exposure to everything that we will be discussing in this series.

Consider the above, in this series we are going to touch on several different aspects.

  1. Technologies to assess movement
  2. Technologies to treat movement
  3. Training technologies to train proper movement

During the course of this discussion, we will talk about various technologies, benefits of using and some of the challenges we experience with.  This is by no means a comprehensive list but is solely based on our experiences only.  So, lets begin by looking at technologies to assess movement.

Traditionally the ability to accurately assess movement was left to large expensive biomechanics labs.   Viacom systems (which is typically used in these labs) are the gold standard in movement assessment and in 3D movement capture.  However, Viacom systems are very expensive and require a lot of time to capture the data, interpret the data and to report it in a meaningful way that can be easily understood by the clinician and athlete.  In an efficient lab, it can take up to 3-4 hours for capturing the data on one player.  This does not include the additional 2-3 hours of data interpretation that must occur after for data reporting in a meaningful way to the consumer.  To be able to do that with an entire team of 18 players or 110, is just not feasible or cost effective.  All would agree this would provide extremely viable data we could use to develop more comprehensive programs, but in the end, the lack of efficiency and the cost make this an option for only a few.

The next level of interpretation would be the use of 3D systems.  One such system out there is the Myomotion system by Noraxon USA.   This system has all the bells and whistles and is truly a portable biomechanics lab.  This system has the ability to provide 3D motion, 2D video, EMG data and force plate data all at the same time.  This system uses 10-13 sensors that are attached to the athlete which then is Bluetoothed to the laptop that is capturing all the data.  

Benefits:

  1. Reliability - this system provides reliable and valid 3D data on the athlete in real time.  
  2. Data Analysis - there is no need for hours of data analysis to put this into a report.  All of the algorithms are run by the computer and this can be printed out instantaneously.  
  3. Portable - this system is portable so you can take this on the field, in the field house or in the athletic training room to do assessments.  
  4. Variability of movements - this system uses sensors to capture all the movements and does not rely on pre-programmed movements.  This allows the user to assess mechanics during a single leg squat and agility drills you create.
Challenges:
  1. Expense - this system is very expensive and runs ~>$25,000+ depending on the capabilities you are looking for.
  2. Data interpretation - although you get this in a report format, there is no interpretation of the data.  Unless you have experience looking at mass biomechanical data, interpreting what the data means and what you do about it is challenging and time consuming.
  3. Sensors - the sensors are cumbersome.  Since you have so many of them, putting them on takes ~20-30 min.  In addition, if you are doing true athletic testing where the athlete sweats, they move all over.  This makes the data that is captured unreliable.
  4. Time needed to test athlete - to perform a typical athletic assessment, this will take 40-60+ minutes per athlete.  This is considering that there is no dropping of the sensor signals and sensors don't move during testing and need re-positioning. 
Another 3D system on the market is DorsaVi USA.  This is an Australia company started by an Australian physiotherapist who saw the need for more reliable way to assess movement in patients and athletes.  DorsaVi uses an inertial measurement unit (IMU) with a magnetometer, gyrometer and accelerometer and provides lab quality data instantaneously.  These sensors capture motion, rotation and acceleration data within 3% of a Viacom system.  


Benefits:

  1. Reliability - this system provides reliable and valid 3D data on the athlete in real time.  
  2. Data Analysis & Reporting - there is no need for hours of data analysis to put this into a report.  All of the algorithms are run by the computer and this can be printed out instantaneously in a comprehensive report.  This provides valid interpretation of the data from which the clinician can easily interpret.
  3. Portable - this system is portable so you can take this on the field, in the field house or in the athletic training room to do assessments.  
  4. Efficiency - this system uses sensors to capture all the movements utilizing a pre-programmed sequence of movements.  This allows for efficient use with teams and requires ~15 min per athlete.
  5. Cost - this system is very well priced and is comparable to the cost of most 2D systems on the market.  
Challenges:
  1. Number of sensors - this system uses two sensors which helps in the efficiency but also limits capturing of movement associated with the pelvis during single limb movements.  Although this will be addressed with future upgrades, this a current limiting factor.
  2. Sensors - these can move and fall off during testing under athletic conditions.  DorsaVi has sleeves which help with this and aids in mitigating this challenge.
  3. Migration of accelerometer - with each rep, the accelerometer graph migrates upward.  Therefore this is reset with each rep but this adds an extra second to each rep.  Although this is one second, it is a variation from natural movement.
  4. Interference - this is really with any 3D system.  if there are strong magnetic fields close to where you are using the system (MRI), then this will create artifact and/or prevent capturing of data.
With the advent of gaming technology, there are several companies offering Xbox One related assessment tools.  Considering number of these companies coming out, this will focus on the use of the Xbox One for assessing human movement.  The Xbox One uses time of flight technology to assess human movement.  In most simplistic terms (and keeping in mind I am not a IT person), this type of system shoots light to the object being assessed and the amount of time that it takes for the reflection to bounce back to the sensor determines the distance from the camera.  From that, a 3D image can be obtained and movement captured.  

Benefits:

  1. Portable - this system is portable so you can take this on the field, in the field house or in the athletic training room to do assessments.  
  2. Efficiency - this system uses the camera (sensor) to capture all the movement so there is no sensor placement on the athlete at all.  Therefore this system is very efficient.
  3. Cost - this systems are very affordable (for the most part).  Although there is one system on the market for over $200,000, most are $1000 or less.  
Challenges:
  1. Reliability - the reliability of the data that is captured is questionable.  If you have ever played a game on one of these systems, we all have experienced where you swing an arm and the system did not capture the movement.  Same thing happens when you do this with human movement.
  2. Environmentally sensitive - these sensors are sensitive to environmental conditions.  If you are testing outside and it is hot, the system can overheat and burn out a sensor.  In one example we went through three sensors doing testing outdoors.  
  3. Light sensitive - these systems are also sensitive to light.  In outdoor very bright conditions it appears to interfere with the time of flight capabilities. 
  4. Artifact - these systems appear to have a lot of artifact in them.  This can be programmed out of the system to account for large variances but when this is done, the movement associated with that individual rep is a guess or based on algorithmic averages.  Most providers of this tech will not tell you this and you won't see it, but understand that is going on behind the scenes.
  5. Interpretation - most of these systems provide you with the data and require the evaluator to interpret the data.
Advances in 3D technology has come light years ahead in the last 4 years and we should see even more advances in the coming years.  Considering, this is a quick review of some of the current 3D technologies out there.  Next week, we will look at some of the 2D technologies out there.

Happy New Year to all.  Honored to have the opportunity to provide this blog and hope you find that what we provide in 2017 is better than 2016.



Dr. Nessler is a practicing physical therapist with over 17 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, December 19, 2016

Challenging the Status Quo - Part VI

Throughout the course of this series, we have been providing some clinical commentary around 5 key areas:
  1. Movement is very complex and very hard for the majority of people to see and assess
  2. The standard of practice is often 5-10 years behind the literature and clinical advancements
  3. There is a strong correlation to improvements in movement efficiency and to mitigating risk of injury and improving athletic performance
  4. We need to recognize where the flaws are in the current ways we assess movement are so that we can become better at what we do
  5. Sometimes movement is just movement and we try to over complicate it
To close out this series, we are going to be talking about how sometimes movement is just movement and we try to over complicate it.  I sometimes amazed how some "experts" in the area of movement come up with some amazing exercises to improve movement.  Yet, I am puzzled by these same individuals and some of the strategies they employ.  As someone who follows the literature, I am not sure how holding my tongue to the roof of my mouth while contracting my abs or holding a balloon in my mouth during abdominal exercise or how rolling around on the floor using pediatric movement patterns will help me move better during cutting or explosive activities.  I am sure there is some form of legitimacy to these exercises and correlations to upright explosive movement.  But I think we tend to over complicate things and when we do things like this, it makes it hard for the athlete to see the correlation.  From a sports psychology standpoint, that to me is just as critical.  Get the athlete's buy in.  If they don't buy in then compliance and effort drops off.  So how do we avoid that?  Don't over complicate it and make it relevant to what they do.

This is not rocket science, this is movement.  We don't have to apply theoretical models, we can simply look at the science and apply what we know.  If we had to limit it to one or two things that we know have a direct correlation to movement and injury risk mitigation and performance enhancement, what would it be?

Depending on who you ask, the answer will vary.  In my opinion, it would be control of frontal plane motion of the lower kinetic chain. Whether you are looking at this picture of this young high school athlete or this professional football player, we can all see how this motion will result in:

  1. Loss of kinetic energy transfer across the system - this means a decrease in power output which will impact vertical jump, sprint speed and agility.
  2. Altered length tension relationships - this means taking a muscle, group of muscles or the entire kinetic chain out of it's optimal position to generate force.  This equates to a decrease in the maximal force that muscle or group of muscles can generate which has a direct impact on athletic performance. 
  3. Altered force attenuation along the lower kinetic chain - this means a increase shear stress departed to the articular cartilage and ligaments and abnormal forces departed to the joints.  This means that tissues break down faster and are more susceptible to injury.

 As we have talked about in the previous blogs, this frontal plane motion "risk factor" can be measured by two components:

  1. The magnitude of motion that occurs.  Frontal plane motion >10 degrees is bad.  The larger the magnitude the worse it is.  
  2. The speed at which this motion occurs.  The faster this motion occurs, the more potential energy that is present and hence the greater force imparted to the structures.  
This is simple physics.  Looking at the force that is imparted to the structures.  Greater  the magnitude over the same time = greater force.  2 equal magnitudes but one occurs faster, than that one generates more force.  In coaching terms, if 2 athletes travel the same distance and athlete 1 travels distance in half the time, he is said to have more power than athlete 2.  As we have stated in previous blogs, the easiest way to see this is with single leg activities.  Some examples and recommended guidelines include:
  1. Single Leg Squat - <10 degrees frontal plane motion and valgus @ <20 degrees per second
  2. Single Leg Hop - <10 degrees of frontal plane motion and valgus @ <100 degrees per second
  3. Single Leg Hop Plant - <10 degrees of frontal plane motion and valgus @ <135 degrees per second
If you have limited time and resources, single leg squat is the quickest and best indicator.  We all realize there are others but if we want to address 80% of the problem, this is where you will get the biggest bang for your buck.  Considering this, do we have to get overly complex in our training?  Again, for the biggest bang for the buck, keep it simple!

  1. Use the concept of repetitions to substitution - do as many reps and sets as they can with proper form.  Once start losing ability to control frontal plane motion, then either step the exercise back to an easier form or stop.  This is the point at which they have reached either muscular, neuromuscular or proprioceptive fatigue.  Training beyond with bad movement will simply reinforce bad movement patterns.
  2. Focus on single limb performance- control frontal plane motion and the speed at which that motion occurs.  This can be accomplished with a plethora of exercises.  
Some samples to start working on single limb performance and controlling frontal plane motion:


Warm up:
Dynamic Lunge:  Key in this exercise is to make sure they are able to get through the motion while controlling the frontal plane motion of the knee.  This is especially important on the step through phase of this exercise.



High Knee Toe Up: Key in this exercise is to bring the leg up into straight flexion and to control the frontal plane motion of the stance leg during.


Strengthening:
Standing Gluteus Medius - this is an endurance exercise for the G.Med but has a single limb performance component.  Make sure to control the frontal plane motion of the knee during the performance of this exercise.


Single leg lumbar hip disassociation - this exercises utilizes the CLX to pull the knee into a valgus and internally rotated position thus requiring greater activation to prevent this motion.  Keep a close eye on the stance limb position during.


Single leg squat - there is no video with this one but the contralateral leg is held in a slight extended position and the athlete squats to 30-45 degrees while maintaining frontal plane control at the knee.

These are some simple exercises we can implement that have a direct impact on the measures we know put athletes at risk.  If we carry this same methodology over to our lunges, step up, squats and other forms of training, then we should see a direct impact on frontal plane motion control.  Keeping it simple and direct to the measures we are measuring is the most direct route to mitigate risk and improve athletic performance.

If you would like more exercises focusing in this area, you can download our free app on IOS and Android by searching "PhysioSports".  The #ACLPlayItSafe app provides four levels of progression to the ACL Play It Safe Program which can be implemented as a part of your team's performance enhancement & injury prevention protocol.

Thank you for following our blog in 2016 and hope you will continue to find this a worthwhile read in 2017.  We will be taking the next 2 weeks off and resuming our blogs on Jan 9, 2017.  To kick off the new year, we will share some technology advancements we have seen that can be leveraged to drive better, faster outcomes with improving movement.

From my family to yours, we wish you and yours a bless, happy and safe holiday season.

God Bless ~ Trent Nessler, PT, MPT, DPT



Dr. Nessler is a practicing physical therapist with over 17 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, December 12, 2016

Challenging the Status Quo - Part V

Throughout the course of this series, we have been questioning the status quo.  This has obviously resonated with a lot of folks as we have had a 400% increase in visits to our blog.  This is great and I am humbled that people want to hear what we have to say.  At the same time, I think we all want to learn more about movement and to do that, we have to challenge the status quo and truly look to push to innovate in the area of technology and movement science.  In this series we have specifically addressed the following:
  1. Movement is very complex and very hard for the majority of people to see and assess
  2. The standard of practice is often 5-10 years behind the literature and clinical advancements
  3. There is a strong correlation to improvements in movement efficiency and to mitigating risk of injury and improving athletic performance
  4. We need to recognize where the flaws are in the current ways we assess movement are so that we can become better at what we do
  5. Sometimes movement is just movement and we try to over complicate it
Last week we had somewhat of a controversial discussion about one of the gold standards in movement assessment, the FMS.  During this discussion we simply highlighted what some of the current research shows about the validity and reliability of this particular test.  It was intended to be a simple discussion of what current research shows us and why that might be the case.  In addition to the discussion, last week's blog leads us right into this week's discussion, which is the standard of practice or care, in my opinion, tends to be the standard of the lazy and status quo. 

Throughout my career, I have been blessed to teach and interact with clinicians from all over the US and abroad.  I often find that there are groups that encounter who are truly inspiring to me.  Super smart, engaged and hungry for more information.  As a therapist, these types of groups (highly educated, versed in the literature, practicing on the cutting edge and highly engaged) can be intimidating.  These are the level of individuals who will challenge you, question you, back their points of view with research.  You truly must be versed in the literature.  At the same time, these are also the groups that I learn the most from and that consistently inspire me to do what I do.  This weekend, I had one such encounter with the opportunity to teach to a group in St. Louis.  Teaching to groups like this encourages me and gives me hope for our respective profession.  But frankly, that represents only 10% of our respective professions.  

In the world of movement assessment, I feel that we tend to be the standard of lazy and status quo. Why do you say that?  If we are doing movement assessment aren't we practicing a higher standard of practice?  Aren't we doing more than 99% of the respective professions?  Are we?  Let's talk about that.  Are we using the gold standard and thinking this is the answer?  Are we using this despite the fact that the literature does not support.  More importantly, that the top risk factors for injury are not even assessed with?  Are we relying solely on 2D technology for movement assessment?  If so, are we keeping abreast of what the research shows us and updating what we do based on?  From what I see, we are not!  Honestly, it goes back to basics.

We talked about the standard of practice so let's take a look at 2D analysis.  There has been numerous conferences I have attended where there is a presentation by someone doing movement assessment using 2D technology. This is great technology and is HUGE in helping our understanding of movement and in educating our patients about movement.  The impact to patient care has been awesome and I applaud those that are using it! However, throughout these presentations there is never any acknowledgement of the limitations this type of technology has.  I have seen clinicians show 5-10 degrees of improvement in pronation at the foot and ankle during gait based on their 2D assessment.  For the audience, we take that for granted that this is accurate.  But is it really?  When performing movement assessment with 2D technology we HAVE to know the limitations.  For example:
  1. Camera angle - a slight pitch of the camera off to the right or left can make it appear as if there is a valgus at the knee that is not there.
  2. Camera tilt - a slight tilt of the camera can make it appear there is movement at the knee, pelvis and foot that is not truly there.
  3. Angles on 2D - unless you are palpating and putting markers on the body and drawing angles from that, then your angles on 2D have an accuracy of +/- 10-15 degrees.  
  4. Tracking on 2D - this is done on pixels (color) and relies on contrast in colors.  If you don't have contrasting colors on the subject to the background, then the tracking becomes much less accurate.
  5. Measuring internal rotation - although we may to be able to visually see internal rotation on video, you can't accurately measure this on 2D video.  This is a 3 dimensional movement that can't be accurately measured on 2D.
  6. Measuring valgus from lateral view - This is a motion that occurs in the frontal plane and must be measured from an anterior or posterior view (anterior preferred).  To try to quantify this frontal plane motion from a lateral view is impossible.  
Some of the biggest mistakes I see.

  1. No standardized placement of cameras.  If you don't control your variables then you never know if the impact you are seeing is the result of camera position or true training impact.  This should include:
    • Height of the camera is same
    • Distance from the subject is same
    • Ensure the camera is straight on with the patient
    • Ensuring the camera is plumb and level 
  2. Frames per second too slow to capture movement - this should be at 120 fps at a minimum.  90 fps will work in most cases but 120 gives a much clearer picture.
  3. Measurement of angles - measurements of angles in 2D is not accurate unless you place markers on bony landmarks.
  4. Measuring valgus or knee position from lateral view during cone hops - frontal plane motion is one of the greatest risk factors and to attempt to measure that from a lateral view is not accurate.
If we are going to assess movement, we need to completely standardize all aspects of the movement capture. If you are using 2D, addressing the above is critical.  Most who do 2D and who read this will think they do.  But do you?  I see a lot of presentations and return to sport calls being made by 2D and when looking at the reports, you can clearly see a lot of this is not being controlled.  It is not a criticism of the individual provider but more a question on whether or not we are doing something that is in the best interest of our athlete.  Make sure what we do is accurate and the only way to do that is take the time to control the above.

If we are making return to play decisions, from a movement perspective, there are several things that I would want to assess.
  1. What is the magnitude of frontal plane motion during single leg activities
  2. What is the speed of the frontal plane motion during single leg activities 
    • Should be <20 degrees per second in single leg squat
    • Should be <100 degrees per second in single leg hop
  3. What is the limb symmetry index during single leg activities 
  4. What is the limb symmetry during functional activities - sprinting
Sadly you very rarely see these assessed.  Can you assess these in a efficient, reliable and affordable way?  Absolutely.  With advances in 3D technology, we now have the ability to look at movement like never before.

We hope you enjoyed this discussion and we will close out this discussion next week.  I would like to take a moment to thank those who have been inspirational to me.  Thank you Todd Ellenbecker, Kevin Wilk, Sam Runfola, Elizabeth Darling,Thiago Lopes, Fabio Machado, Justin Sampley, Lesley Parrish, Carl DeRosa and my lovely wife and children.


Dr. Nessler is a practicing physical therapist with over 17 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, December 5, 2016

Challenging the Status Quo - Part IV

Over the course of the last couple of weeks, we have been providing some clinical commentary on what we have learned in 20 years of clinical practice and over 15 years in movement assessment.  Obviously, we can't encapsulate everything we have learned in a blog or two but we can provide some insights.  We have begun to discuss in detail, over the last 2 weeks, that we need to recognize where the flaws are in our current ways we assess so we can do things better.
  
During the last 2 weeks we went into depth on some movements we can look at and what the research tells us about how we should look at them.  Assessing these movements as described in the literature should and will guide our specific interventions.  At the beginning of this section, we highlighted what we know are well documented movement risk factors.  As a point of reference, these are:
The above referenced articles are only a few of the large number of studies showing the same thing. So although there is only one referenced here, these are some of the more current ones that have been done over the last 10 years highlighting the same risk factors.  Based on the literature, we know several things.
  1. Frontal plane motion of the knee greater than 10 degrees in motion is bad!  The larger the magnitude of this motion, the worse it is.  An athlete that has 20 degrees of frontal plane motion is at greater risk than an athlete with 10 degrees of frontal plane motion.
  2. Speed at which this motion occurs is a risk factor!  An athlete that has10 degrees of motion that occurs slowly is at less risk than an athlete that has 10 degrees that happens very fast.  Although we have not published this, some guidelines we see are: 
    •   In a single leg squat if valgus occurs at >20 degrees per second, then the athlete is at greater risk
    • In a single leg hop if valgus occurs at >100 degrees per second, then the athlete is at greater risk
  3. >20% variance in single limb symmetry is bad!  Keep in mind, an athlete can move equally bad on both legs so although, in this scenario, they are symmetrical, it is still bad.  But overall, a >20% variance is bad.  Larger the variance, the greater the risk.
  4. Asymmetry (shifting weight to one side) during the squatting motion is bad!  Whether you call it a lateral shift or lateral displacement of the pelvis during a squatting motion, this has a direct impact on force attenuation and force generation.  The larger the asymmetry is during the squat the greater the risk is.   
  5. Inability to maintain core stability within 10 degrees is bad!  This should be assessed for the ability to maintain stability in flexion/extension and rotation. 
In addition to the above, we also know there are demographic risk factors that should be considered.  

Considering all the above, then we should take a look at the standard of practice for movement assessment in athletics.  Remember the intent is to question the status quo so that we can do what we do better.  At the end of the day, we are not concerned about offending people, but rather prevent more injuries in our athletes!  As such, most would agree the most commonly used movement assessment today is the Functional Movement Screen or FMS.  For those of us familiar with the FMS, we recognize that the research based risk factors noted above is not assessed using the FMS.  Looking at some of the specific movements:

  • Overhead squat - assesses several factors but is not assessing lateral displacement of the pelvis or lateral shift
  • Hurdle step & In-line lunge - although they are measuring asymmetry of motion assessed with the FMS, it is not assessing magnitude or speed of frontal plane motion of the knee during SL performance or the asymmetry of this frontal plane motion.
  • Trunk stability and rotational stability test have little research support related to their correlation and core stability in sport.
In addition to the above, some additional challenges:

  • Fatigue not assessed.  Does 3 repetitions performed with each exercise give a true picture of what the athlete looks like in sport.
  •  Demographic risk factors not considered in overall risk rating.
  • Composite score of 21 is not sensitive enough to detect minor improvements in movement.
Considering the above, then the results of some of the current research is not a surprise.  Some of the current studies include:

  • Bardenett et al - Int J Sports Phy Ther 2015 - looked at the FMS as a predictive tool in high school athletes.  Of the 167 high school athletes that were assessed during the pre-season, the results showed the FMS was good at recognizing asymmetry in the movements tested.  But they found that the results were not a good at predicting injury.
  • Dorrel et al - J Ath Train 2015 - performed a systematic review and meta-analysis of research from 1998 to 2014.  What the results showed was that the FMS demonstrated low predictive validity for injury prediction and leading the authors to conclude that this should not be used for injury prediction.
  • Bushman et al Am J Sports Med 2016 - looked at the FMS as a predictive tool in active male soldiers.  Of the 2476 soldiers assessed, the FMS demonstrated low sensitivity and low positive predictive value.  This lead the authors to conclude this could lead to misclassification of injury risk in military personnel.  If they are assigned to hazardous duty as a result of this misclassification, it could potentially place the soldier at greater risk.
  • Frost et al J Strength Cond Res 2013 - did the FMS on healthy firefighters and scored each on the assessment.  This was followed 3 minutes later by performing the test again but just prior to testing each firefighter was instructed on what they were being scored on.  Each participant had an average of 2.6 point (12.4%) improvement in their overall score with just knowledge of how the test is scored. 
  • Wright et al Bri J Sports Med 2016 - in this clinical commentary based on the literature review showing a low sensitivity of 24% led the authors of this paper recommending that this should not be used for injury prediction or for making return to sport calls.
Despite all the above, the FMS has been instrumental in advancing what we know about movement and screening for risk.  The FMS and the developers behind it have been instrumental in the creating this shift to look more closely at movement.  As a result, the positive impact they have had on the field and injury prevention is immeasurable.  But as a science, we must advance based on what we know.  Consider, can we do it better?

We hope you enjoyed this week's commentary and hopefully it provoked some new thoughts.  Next week we will close this out with looking at not over complicating movement and raising the standard of practice. 



Dr. Nessler is a practicing physical therapist with over 17 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, November 28, 2016

Question Status Quo - Part IIIb

Over the course of the last couple of weeks, we have been providing some clinical commentary on what we have learned in 20 years of clinical practice and over 15 years in movement assessment.  Specifically some clear conclusions which we have begun to discuss in detail.  These include:
  1. Movement is very complex and very hard for the majority of people to see and assess
  2. The standard of practice is often 5-10 years behind the literature and clinical advancements
  3. There is a strong correlation to improvements in movement efficiency and to mitigating risk of injury and improving athletic performance
  4. We need to recognize where the flaws are in the current ways we assess movement are so that we can become better at what we do
  5. Sometimes movement is just movement and we try to over complicate it
  6. The standard of practice or care, in my opinion, tends to be the standard of the lazy and status quo. 
Last week, we began to discuss the need to recognize the flaws in our current methodology and what can we do better.  Knowing the need for efficiency, we also made a couple of suggestions on movements we should assess quickly and how the research tells us we should look at.  Last week, we looked at the single leg squat and single leg hop in detail.  Today, we will expand on that.

Over the course of the last 2 decades, clinically, I have always felt the core was a key component to stability of the lower and upper kinetic chain.  Using the lower kinetic chain as an example, having a stable surface to pull on, it made sense the quads, hams, gluts, etc could then generate much more force than with an unstable core.  The analogy I always used in the clinic is sitting on a rolling stool is to have a patient pull on you without securing yourself.  They pulled on you and you roll.  Now repeat this and stabilize yourself so you don't roll.  How much more force can they generate pulling on you?  Why?  Because they are pulling on a stable surface.  This analogy applies to the ability of the quads/hams being able to generate more force when they are pulling against a stable surface.  At the same time, providing a stable surface also provides proper length tension relationships for the muscles of the lower quarter which has a direct impact on force production. 

Ironically, this has also been vetted in the literature in the last 10+ years.  Chaudhari et al Am J Sport Med 14 showed that professional baseball players who had poor core stability were 3 to 2.2 times more likely to miss 30 days throughout the baseball season.  These players reported more shoulder injuries than those players with a stable core.  Chaudhari et al J Strength Cond Res 11 also showed the impact improvements in core strength have on athletic performance.  In this study, they showed that pitchers who had improvements in core stability also had walked less players and less hits per inning.  Although it has not been vetted in the research yet, I would hypothesize that improvements in core stability also has a direct impact on pitching velocity.  There is also a correlation to core strength and lower kinetic chain injury risk.  Frank et al  Am J Sport Med 2013 also showed that improvements in core stability resulted in decreases frontal plane motion of the knee which decreases stress to the ACL.  We now know the impact this has on lower limb injury risk but what about performance?  Hoshikawa et al J Strength Cond Res 13 showed that improvements in core stability had an impact on vertical jump.  So based on the above, we obviously need to test the core.  So if we do test the core, what should we test or how should we test it?

Tong et al Phys Ther Sport 14 showed high EMG activity of the core during the plank test.  Looking back at the basics (Nordin & Frankel - Basic Biomechanics of the Musculoskeletal System) we know that 10 degrees of motion of the spine from neutral in flex/ext or rotation puts a lot of stress on the structures of the spine.  If this motion occurs under high loads associated with sport (which range from 4-8 times body weight) that this not only compromises the structures of the spine but also the lower kinetic chain.  Therefore, stability of the spine (within 10 degrees of flexion/extension and rotation) during this test is one thing that should be evaluated.  Norms for this test vary by age and Strand et al J Human Kin 14 have shown what some variations are by age.  For athletes, this should be a sustained position for 1 minute.  During this time, close attention should be paid to the stability of the spine in this position in the previously mentioned motions. 


Most people who perform the plank do it incorrectly.  The key to this motion is to ensure the hip and spine are in a neutral position.  As depicted here, training and testing in this position has a much better carry over to upright posturing and is a better indication of true stability in these neutral positions. 

In addition to the plank test, another test that should be considered is the side plank test.  Ekstrom et al J Orth Sport Phy Ther 07 showed highest EMG activity in the side plank was with the gluteus medius.  So the side plank is an excellent test for assessing the strength and endurance of the core and the gluteus medius.  Just as noted previously, this test should be assessed for the ability to sustain the position in neutral spine in lateral sidebending as well as rotation.  As stated previously, there are norms published for this test but for most athletes, testing this position should be done for 1 minute time.

The side plank, like the plank is often done incorrectly.  The testing position should be similar to what is depicted here in this picture.  All too often, athletes will position themselves in position that shortens the gluteus medius which will then limit the strengthening of this muscle.  Doing this during the test will decrease the reliability this will have to hypothesis about glut strength, especially in single leg stance and result in less than optimal training carry over to sport. 

*Note on Side Plank - over the course of the last 10 years in using this as a part of our testing with athletes, we have found some correlations that we have yet to see in the published literature.  One of those we want to highlight because this is critical to our interpretation and associated intervention.  Depicted here is what we term tibial drop.  The athlete (basketball player) is unable to maintain a neutral ankle position during this test.  This is most likely the result of ankle weakness and in this case, associated with a history of chronic ankle sprains.  If we had not been looking at the feet during a side plank position this would have been missed and the athlete would have scored low.  The hypothesis for this would have been weak glut medius.  The program that would have been implemented may have had some impact but think we would all agree not near the impact as if we addressed the foot/ankle weakness.

Over the course of the last couple of weeks, we have talked about what we should look at.  Hopefully the discussion on single limb testing and core testing provides some insight and guidance on where the literature is leading us.  Next week, we will close out this portion on the movement aspect by looking at the specific research related to some of the fallacies with current assessments we use, what the research tells us and how we can apply.



Dr. Nessler is a practicing physical therapist with over 17 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.