Monday, October 15, 2018

How Does Human Movement Occur - Kinetic Chain in Action - Part II

Posture

Posture is an intentional or habitual assumed position.  The definition includes physical carriage, or the way one holds his or her body and body position, which refers to the various position(s) the body can assume.  Another way to look at posture is to think of the “arrangement of body parts,” or in other words, the way that the components of the body are aligned in relation to each other.

What does posture tell us that is important in our discussion of the kinetic chain and movement, specifically pathokinematic movement?  Posture can tell us a tremendous amount about symmetry, strength, tightness and the potential for injury in the body.  For our purposes here, we will define human posture, or the arrangement of the body and limbs, in terms of a static (fixed) position.  It is a motionless position or stance of natural comfort.  According to Kendall et al “in standard posture, the spine presents the normal curves and the bones of the lower extremities are in ideal alignment for weight bearing. The neutral position of the pelvis is conducive to good alignment of the abdomen and trunk, and that of the extremities below.  This aids in the optimal performance of the core as well as the lower extremities.”  Kendall et al, (1993) further state that “the chest and upper back are in a position that favors optimal function of the respiratory organs. The head is erect in a well balanced position that minimizes stress on the neck musculature.”[i]

In this “optimal position” the cartilage, joints, ligaments, muscles and tendons are loaded in the “optimal fashion” or placed in “correct” length tension relationships (the relationship between the length of the muscle and the force it can exert) and the overall efficiency of the system is maximized.  We will discuss this more in Chapter 5 when we look at pathokinematics and performance.

During work, school, exercise or training activities individuals can develop poor posture, meaning posture that is outside of this “optimal position.”  If poor posture is not corrected or addressed otherwise with training protocols, this can lead to what Janda, et al (1996) refer to as “Crossed Pelvic Syndrome.”  Janda describes this as occurring when there is:


§  Weakness or inhibition of the lower abdominals (or transverse abdominus)


§  Tightness of the hip flexors (iliopsoas) and gluteus maximus/lower lumbar spine[ii]


This not only impacts the potential for low back pain but can also have a dramatic impact on force production, strength and endurance of the entire kinetic chain.  Visually, these postural anomalies can be observed both from anterior and lateral views, although they are easiest to see from the lateral view.  Some postural anomalies we can observe from the lateral aspect include but are not limited to:


·       Forward head – increased extension of upper cervical spine and forward flexion of lower cervical upper thoracic spine

·       Rounded shoulder – protraction of the scapula

·       Increased lumbar lordosis – anterior pelvic tilt with butt tucked in and hips slightly forward

·       Increased genu recurvatum – hyperextension at the knee


Some postural abnormalities that we observe from the anterior or posterior aspect include but are not limited to:

·       Cervical sidebending – head is tilted to one side or the other

·       Shoulder depression – one shoulder appears lower than the other

·       Scapular tipping or winging – where the inferior border (tipping) or medial border (winging) is more prominent

·       Scoliosis –curvature of the spine

·       Pelvic asymmetry – one ileum or iliac crest appears higher than the other

·       Hip adduction – where the hip or femur appears to be more toward the midline

·       Genu valgum - knees touch, but ankles do not (knock-knee); or varum - outward curvature of one or both legs at the knee (bowleg)

·       Foot pronation - foot turns outward, ankle rolls toward center; or supination - foot turns inward, ankle rolls outward.


 

Certain postures, and particularly abnormalities in posture like those described above, can provide invaluable information about muscle tightness, muscle imbalances and potential injury and performance issues as noted earlier.  For example, if we are performing a visual examination of a college baseball pitcher, we may notice some deviations commonly seen in pitchers.  This would include but is not limited to:  scapular protraction and depression, scapular winging, thoracic and lumbar scoliosis, pelvic asymmetry, hip adduction, genu valgum and foot pronation.  For the college pitcher, this can be the result of years and years of participation in a sport that requires an asymmetrical or one-sided position.  If this asymmetry is not addressed with training both during the season and after, tightness and weakness can result that can lead to injury and decrease performance.  Let’s look at a few postural deviations more closely, reviewing the likely causes, potential injuries that can occur, and a few of the performance issues that can arise:

Shoulder depression/winging:

·       Causative factors – throwing is predominately an asymmetrical activity resulting in over development of some of the shoulder muscles on the throwing arm as well as underdevelopment of some of the muscles of the same shoulder.  With over development, the non-throwing arm appears underdeveloped in relation to the throwing arm.  Throwing results in tightness of anterior structures on the throwing arm which then in turn results in the scapula resting in a more
protracted and depressed position on the thoracic spine.  This can be the result of tightness of the anterior structures (pectorals, etc.) and weakness of the posterior structures (rhomboids, etc). 

The rhomboids originate on the spinous processes of the thoracic spine and insert on the medial border of the scapula from the scapular spine to the inferior border.  Collectively, they act to retract and downwardly rotate the scapula during upper extremity movement.  Winging is highly associated with weakness of the serratus anterior muscle.  The serratus anterior originates on the upper eight ribs and inserts along the entire anterior medial border of the scapula.  When the serratus anterior contracts, it depresses the medial border of the scapula against the thoracic cage, thereby aiding in the stability of the scapula during upper extremity movements and when the arm is elevated.  If this muscle is weak, then the scapula will wing through shoulder motion, and most predominately in the range from 90 to 120 degrees of shoulder flexion.  These positions are common for the shoulder during throwing motions or participation in over head sports. 

·       Potential injuries – with the scapula sitting in a more depressed and protracted position, there are several tissues that are compromised.  In this posture, there is a significant reduction in the subacromial space (space between the head of the humerus and the acromion).  Since this is the space that the supraspinatus and portions of the infraspinatus tendons pass through to their attachment on the greater tuberosity, a reduction of this space increases the potential for irritation and tears of the tendons, especially during overhead activities like throwing.  This position also results in compression of the anterior structures of the shoulder, specifically the long head of the biceps and the anterior labrum.  Both the long head of the biceps and the labrum are further compromised by the cocking phase of throwing.

·       Performance issues – with the distorted position of the scapula on the thoracic cage, the length tension relationships of many of the muscles associated with stability of the scapula as well as the rotator cuff are significantly altered.  If the scapula stabilizers and the rotator cuff are weakened, then the transfer of kinetic energy across the system will not be as efficient and there will be decreased power output.  This can lead to (in this case) a decrease in pitching velocity or a decrease in the ability to sustain velocity from one inning to the next.

Next week we will continue with looking at the Thoracic spine.  As basic as it sounds, to truly change movement, we must change the way that we think.  And although it is not 100% data driven, it is 150% science driven.  Over the course of the next month, I will continue to provide blogs to help us all understand better the sciences behind movement and why we should do what we should do.  And that is, assess it better.  Move better, feel better, perform better and last longer.  That simple!   
Next week, we will start to dissect this a little more.  If you are enjoying our blog, please share it and follow us on twitter @ACL_prevention and on Instagram at @Bjjpt_acl_guy 


Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment and ACL injury prevention.  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, October 8, 2018

How Does Human Movement Occur - Kinetic Chain in Action

I went broke believing that the simple should be hard.
Matt Nathanson

In order to develop strategies which will improve movement, and eliminate pathokinematics in our athletes and others we work with, we must first understand how human movement occurs in the first place.  Our understanding of the human body and the systems that make it work, as vast as it is, is still so limited when it comes to its full and integral complexities.  For our purposes and the purposes of this blog, we mostly focus on the musculoskeletal system (skeletal system, muscles, cartilage, ligaments, tendons and joints), the nervous system (neuromuscular system - sensory and motor nerves and central nervous system – higher centers and spinal cord) and the cardiovascular system (heart, lungs, veins and arteries), and how they work together so that the body can move.   

However, the human body is an extraordinarily complex interaction of these and many other systems that influence its action, health and wellness.  The human body relies on the “optimal performance” of all of these systems in order to provide optimal performance in life and in sports.  If there is a break in any of the systems or “links in the chain,” then optimal performance cannot be obtained, and over time, damage can occur. 

The Kinetic Chain

Human movement occurs thanks to the “kinetic chain.”  Kinetic means force, and chain is defined as a system that is linked together.  Throughout this book, when we refer to the kinetic chain, we are referring to the system of interconnected body segments that allows the body to move.  For our purposes, the kinetic chain includes the parts of the body which directly or indirectly impact the positioning, alignment, strength, endurance and performance of proximal or distal segments of the body.  The nervous system, the musculoskeletal system, as well as the cardiovascular system, all work together to transfer energy or force through the body to the extremities in order to cause movement.  The majority of this text is focused on the lower kinetic chain, which for our purposes refers to all of the muscles, bones, ligaments, tendons, joints and all associated neurological input systems that influence those structures from the chest (pectoral muscles) to the feet. 

A kinetic chain can be open or closed.  A closed kinetic chain is one in which the hand or foot, or other moving body part, is in a fixed position during movement.  In this type of movement, because one or more extremity is stationary, resistance from the stationary surface is felt throughout the entire body, including and especially in the trunk, and specifically in the core.  In closed kinetic chain situations, when movement occurs all of the connected segments of the body are involved simultaneously.  An open kinetic chain is one in which the extremity or extremities are not fixed to any stationary surface and are therefore simply free in space.  In an open kinetic chain only the part of the body that is free in space and those parts closest to it are directly involved in the movement.

Therefore, in a closed kinetic chain, the parts of the system act in dynamic unison and in an open kinetic chain, they act more in isolated segments.  Most sports and functional life activities are closed kinetic chain activities, since in most cases the body or one of its extremities is fixed against a stationary object or surface (the ground, a chair, etc.) and all parts of the body work together dynamically.  Consequently, closed kinetic chain exercises require and reinforce recruitment patterns of the neurological, muscular and skeletal systems in ways that most closely mimic those used in sports and the activities of daily life.  They are the most effective for improving movement, preventing injury and enhancing sports performance, since they are more like sporting and “real life activities.”  Examples of exercises that are closed kinetic chain are squats and push-ups.  In comparison, leg extensions and triceps push-downs are examples of open kinetic chain exercises. 

How can we see the kinetic chain in action so that we can ultimately understand how movement occurs?  One way is to look the arrangement of the parts of the body by looking closely at the musculoskeletal system.  When we refer to the musculoskeletal system, we are referring primarily to the skeletal system, (bones), and the muscles, ligaments, tendons, other connective tissue and joints that hold the skeletal system in place.  We can see this system at work both when the body is still (statically) and when the body is in motion (dynamically).  Let’s begin by looking at the posture of an individual in a standing and stationary position.

As basic as it sounds, to truly change movement, we must change the way that we think.  And although it is not 100% data driven, it is 150% science driven.  Over the course of the next month, I blogs to help us all understand better the sciences behind movement and why we should do what we should do.  And that is, assess it better.  Move better, feel better, perform better and last longer.  That simple!   

Next week, we will start to dissect this a little more.  If you are enjoying our blog, please share it and follow us on twitter @ACL_prevention and on Instagram at @Bjjpt_acl_guy 


Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment and ACL injury prevention.  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, October 1, 2018

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

Over the course of the last several weeks, we have discussed injury rates among NFL players and the impact this has on individual performance and overall team performance.  Obviously with such a high percentage of these being non-contact in orientation, prevention is the key.  You would think with the advent of technologies and advancements in movement, rehabilitation and performance sciences that we would have figured this out by now.  Apparently, we have not!

If you look at this list here, you can see we have a long way to go.  Pictured here are the players who have torn their ACL in the NFL as of 9.28.18.  Sadly, the number of ACLs that have occurred thus far are on trend to be representative of what has happened in the last 5 years.  If you look at this data, 29 of these occurred in preseason.  The remaining within the first couple of weeks of the season.  If you look at the mechanism of injury, you again see that >70% of these are non-contact in orientation.  The financial impact and the impact to individual and team performance has yet to be fully recognized.  Insanity - To do the same thing over and over and expect a different outcome!  Sadly, for the last 5 years, I have made this same statement.  How can we expect a different result if all we do is the same thing year over year. 

In our first section, we discussed what we should be assessing to determine risk.  Whether you are a NFL player, an elite athlete or a high school athlete, the literature is pretty clear that dynamic valgus is something we need to make sure to assess.  Yet, the majority of testing in the NFL uses assessments (movement screens) that have not been well validated in the research to be predictive of injury and which do not assess dynamic valgus.  In addition, many teams also use test which assess limb symmetry index.  Limb symmetry index (LSI) is the variance between your right leg and left leg during functional testing (single leg hop, single leg hop for distance, single leg triple hop).  Most of the research indicates if you have >15% variance then you are at greater risk for injury.  But, is that good enough?

It makes sense if you have a huge variance between the right side and the left side that you are at greater risk.  That would mean that you would always be putting more wear and tear on one side and the side that is weaker would be at greater risk because it is underdeveloped and may not be as resistance to the high forces associated with the sport when you are force to use it.  However, does an LSI of 100% mean you are at less risk?

Take the athlete depicted here.  In single limb testing, this athlete may present as 100% symmetrical.  But is that 100% of good movement?  I think we would all agree, this athlete is still at risk despite the fact that she is 100% symmetrical.  That is exactly what a study by Wellsandt et al in the 2017 Journal of Orthopedic & Sports Physical Therapy showed. 

Methods:
70 athletes completed quadriceps strength and 4 single leg hop tests before ACLR and 6 months after ACLR.  LSI for each test compared 6 month post op involved limb measures to involved 6 months post op measures.  Second ACL injuries were tracked for a minimum follow up of 2 years after ACLR.

Results:
57.1% (40) patients achieved 90% LSI for quadriceps strength and all single leg hop tests.  11 (15.7%) of patients sustained a 2nd ACL injury in the 2 year follow up period.  8 of the 11 patients with second ACL injury passed the 90% LSI return to sport criteria in quadriceps strength and single leg hop tests 6 months after the initial ACLR.

Discussion:
72.7% (8 of 11) of the patients who suffered a second ACL injury achieved 90% LSI.  Although that is only 20% (8 of the 40) of those who achieved 90% LSI, it begs the question on whether LSI should be the sole measure of return to play.  In many cases and as a standard of practice, this is often the case. 

So is the answer adding additional tests to capture true deficits?  Toole et al in the 2017 Journal of Orthopedic & Sport Physical Therapy looked at this in youth athletics.  What the authors found is when you add the recommended tests from the literature for RTPlay following ACLR reconstruction, you end up with:

  • IKDC - score 90 or better
  • 90% LSI on:
    • Quad/Ham strength
    • SL Hop
    • Triple Hop
    • Cross over hop
    • 6 meter timed test
In this study, the authors applied this criteria to 115 young athletes and found:
  • 13.9% met all the criteria
  • 43.5 to 78.3% met criteria on the individual tests

So, is it that our rehabilitation is not preparing people properly for functional testing and return to play or that we are not measuring the right things?  If we think back to part I of this discussion, we know we need to measure dynamic valgus and yet none of these tests are doing that.  So, do we continue to do the same thing and expect different results or do we try something different?

With the advent of wearable sensor technology we now have a way to accurately measure dynamic valgus.  Not only can we capture the magnitude of motion that occurs but also the speed at which it occurs.  Finally, we have a solution.  Once those at risk have been identified, we can now create programs to change those movements.  There are multiple programs out there that can efficiently impact these pathokinematics and improve the movements that put athletes at risk. 

Insanity - To do the same thing over and over and expect a different outcome.  Is it time for the insanity to be over or are we going to continue what we have always done and expect a different result?  I chose the former.  If you are enjoying our blog, please share it and follow us on twitter @ACL_prevention and on Instagram at @Bjjpt_acl_guy 


Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment and ACL injury prevention.  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, September 24, 2018

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

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

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

  • Coaching decision.  The coach may choose to not start the player due to their current performance.  They see that the player is making less tackles which means more players are getting by them which may result in more yardage per carry for the opposing team or TDs.  Net result is a decrease in the team’s performance.  The coach may also see that one of their star players is no longer one of their star players.  Coaches are there to win games and that depends on results of the individual players.  If a player’s stats drop, that means an opportunity for another player to move up.
  • Medical decision.  We know that athlete who have an ACLR are at greater risk for other lower kinetic chain injuries.  They also tend to have more knee problems and knee pain with RTplay.  This may result in the ATC or MD pulling them out of play or modifying their play based on how their knee is responding.
  • Player decision.  This is one that typically does not last long.  If the player is self-limiting their play, they may be pulled by the coach or cut from the team.  A lot of times, athletes will suffer from Kinesiophobia (fear of movement) after an ACLR.  This is where the athlete has not developed 100% confidence in their knee and its ability under the high demands of this sport, so they may self-regulate.  This is most common with those who suffer a non-contact ACL injury and typically have kinesiophobia with explosive movements and cutting movements.  Net result is a decrease in agility which may be one reason for a decrease in number of solo tackles.
Several recent studies have looked at kinesiophobia a little closer.  Noehren et al Ortho J Sport Med 2018, looked at the impact that kinesiophobia (fear of movement) has on loading patterns of the lower extremity during a drop vertical jump.  What the authors found was that athletes who reported high levels of kinesiophobia tend to unload their involved limb during landing.  This can have a significant impact on loads on the non-involved side (increasing risk for injury on that side) and strength development on the involved side.  If the athlete is shifting their weight over to the non-involved leg, this means they will carry this over to functional tasks and strength training.  This will add to a muscle imbalance on the involved versus non-involved side.  The asymmetry that is created sets an athlete up for future injury but also negatively impacts performance. 

One of the things we see in athletes that report high levels of kinesiophobia is what we term a lateral shift.  As depicted in this picture here, when we evaluate a squatting motion in an athlete who reports high levels of kinesiophobia, what we see is that athlete then shifts their weight off the involved side and more to the uninvolved side.  If this is not corrected, then this athlete will carry this over to all their functional activities (sitting down, getting off bed, getting in/out of car) and during their training.  The same lateral shift that is depicted in this picture here is carried over to when the athlete gets under a loaded bar and does squats.  This further reinforces the asymmetry and motor and muscle sequencing that we don't to see.

Paterno et al Sport Health 2018, looked further at this concept of kinesiophobia and found some interesting results. In this particular study, they looked at athletes that have been cleared for RTPlay following an ACL reconstruction.  Each athlete in this study:

  • Performed Biodex testing to determine symmetry of quadriceps strength
  • Performed SL Hop testing to determine distance symmetry 
  • Filled out the TSK-11 (Tampa Scale for Kinesiophobia 11)
What the authors found was high scores on the TSK-11 (high incidence of fear) were correlated to athletes who were:
  • 4xs more likely to self report a decrease in activity
  • 7xs more likely to have decrease limb symmetry index (a % comparison of how the right compares to the left)
  • 6xs more likely to have a quad deficit
  • 13xs more likely to reinjure
As a practitioner, one thing this brings up is it the fear that drives these results or the results that create some subconscious awareness of the limitation which drives the fear?  We don't really know that answer but what we do know is that there are certain personality types that tend to demonstrate these fearful tendencies more than others.  As such, we must be able to identify them early on in the process and do everything we can not to feed into it.  At the same time, create exercise progressions which help to overcome.

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

On a personal level, what is the impact to that athlete?  This is obviously the individual that is impacted the most.  NFL players know this impact and it is one reason that in 2014, 2015 and 2016, knee injuries were ranked the #1 concern among NFL football players in the NFL Players’ Association.  This is above concussion or any other injury.  Why?  Because they know how much this impacts earning potential.  This has a direct impact on the NFL player’s earning potential in 2 ways.  If their contract is up for negotiation, this is going to be based on prior year’s performance.  If they are starting in less games and making less solo tackles, then they do not have as strong negotiating power as they may have had previously.  In addition, what this study shows and what the athletes know, is that their professional football career is cut short.  Although this study shows an impact, what industry experts say is that their professional career may be reduced by 3-4 years.  On a multimillion dollar contract, that is a lot of potential income that they lose out on.

So why is this study so important?  ACL injuries are common in the NFL.  How common?    Let’s look at the numbers by season. 
  • 2016/17 – 46 ACL injuries 
  • 2015/16 – 48 ACL injuries  
  • 2014/15 – 45 ACL injuries 
  • 2013/14 – 63 ACL injuries
Over four seasons that is 202 ACL injuries.  If you look at the overall cost of those injuries, you must look at time loss, ACLR cost, rehab cost, positional replacement costs, emotional capital and impact to team performance.  Industry experts put this cost at ~$1M/player.  Over 4 seasons, that is $202M in injuries.  

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

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

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

Insanity - To do the same thing over and over and expect a different outcome.  Is it time for the insanity to be over or are we going to continue what we have always done and expect a different result?  I chose the former.  Next week, we will close out this discussion with talking about how do we determine RTplay?  If you are enjoying our blog, please share it and follow us on twitter @ACL_prevention and on Instagram at @Bjjpt_acl_guy 


Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment and ACL injury prevention.  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, September 17, 2018

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

As the 2018 football season kicks off, every football fan wants to know, how will my team do this year?  What if I told you, you may have some insight to how they are going to perform based on their percentage of knee injuries.  If you look at the number of reported knee injuries by NFL team for the 2014-2017 seasons and compare that to recorded wins for those teams, what you find is that teams with the highest % of knee injuries won 33.9% of the time vs. teams with lower knee injury rates won 52.7% of the time.  Why is that?  Lot of reasons for this but one of the primary is that players that tend to get injured more are players who play more, so your better players.  They have more athletic exposures and as such have a great risk of being injured.  So, when the better players are taken out of the game or season, this can have a huge impact on the team's seasonal performance.

One of the most devastating injuries to a professional football player is the anterior cruciate ligament (ACL) injury.  Why is that?  Because the impact this has on their professional career.  A great research article came out earlier this year that highlighted this fact.  In a study by Mai et al Am J Sports Med 2018, the authors looked at the impact that an ACL injury has on athletic performance and the length of professional career in NFL, NBA, NHL and MLB players.  Not only was NFL players performance decreased for 2 years after the ACL but their professional career was also cut short by 2 years on the average.   In a systematic review published by Mohtadi et al Am J Sports Med 2017, their study found similar results.  That although most players return to play, performance measures and stats across the board were reduced following an ACL injury.  So the obvious question becomes, how do we prevent knee injuries in athletics?  So how do you know how your team is going to do?  Look at their preseason ACL and knee injuries.  In the last 5 years alone, there has been an average of 23 ACL injuries prior to week 1 of the NFL season.  23 ACL injuries occurring in preseason camp.  This is more than 1/3 of the ACL injuries that occur during the entire season occur before an official snap has been taken in an NFL game. 

Throughout the course of this blog, we provided some thoughts and research on several factors that contribute to altered biomechanics or pathokinematics that put athletes at risk for an Anterior Cruciate Ligament (ACL) injury.  In a recent study by Johnston et al Am J Sports Med 2018, they performed video analysis of 156 ACL injuries during the 2013-2016 seasons.  What they found was 72.5% of these injuries were non-contact in orientation, meaning no contact with another player or object.  This is important because these are the ones that we could potentially impact and reduce.  Upon review of the video of each of these non-contact ACL injuries, what they found was the limb was in a dynamic valgus position. As pictured below, this can happen when an athlete plants their foot and cuts to the opposite direction.  The limb falling into this position under high loads and high speeds results in a rupture of the ACL. 


In the Johnson study, this led the authors to suggest that we need develop programs that create control of these motions under athletic loads.  We may think this is isolated for professional athletes, but in a recent study by Owusu-Akyaw et al Am J Sports Med 2018, the authors determined this is the same position the lower limb is in when non-professional high school and college athletes suffer a non-contact ACL injury.

Throughout the history of this blog, we have attempted to correlate these same pathokinematics to not only ACL risk but also to changes in athletic and team performance.  The previously mentioned studies further highlight this.  In this authors mind, there are two ways in which these injuries impact performance; directly or indirectly.

The direct impact is the impact that altered biomechanics has to force production and kinetic energy transfer.  When the limb moves, like depicted in this picture, this results in altered length tension relationships for muscles and altered loading patterns.  Simply stated, due to the altered mechanics, the muscles of the core and/or lower kinetic chain are placed in a shortened or lengthened position.  Knowing the impact that length (shortening or lengthening) has on force production, then the muscle cannot produce as much force or power as it could if it were in an ideal length tension relationship.  This results in muscles of the core and lower kinetic chain producing less force.  This means the athlete has decreased hitting force coming off the line, less explosive power to sprint for 50 yard touchdown, or decreased efficiency of movement resulting in altered agility or ability to avoid the tackle.  So these movements have a direct impact on the individual athletes performance.

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

Case in point, a recent study by Read et al, Am J Sport Med2017, the authors looked at the impact of ACL injuries have on future performance in National Football League (NFL) players. For the purposes of this discussion, we are going to dive into this one in more depth.  

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

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

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

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


Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment and ACL injury prevention.  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, September 10, 2018

Runner's Knee - Part V

Last week, we continued our discussion on how to prevent runner's knee with a discussion of some exercises that can be done for recovery as well as some post run training that helps reduce injuries and performance.  This week, we will wrap up our discussion starting with when should you see the MD for your knee pain?
  • When should a runner go to the doctor for their runner's knee?  In many states, you can see a physical therapist for your knee pain and have this covered by your insurance without seeing a physician.  As the musculoskeletal and movement experts, this can often expedite your return to running pain free.  However, it is important to make sure you get with a therapist who understands runners, running biomechanics and the nuances of dealing with runners.  So make sure to do your research.  
    • Some key indications that you should go see a doctor or a physical therapist:
      • Your pain is preventing you from running.
      • Your pain is limiting your activities of daily living.  In other words, you are having pain with ascending/descending stairs, walking long distances, or it is impending your ability to work or stand for prolonged periods.
      • If you feel like your pain is progressively getting worse.  How do you know if it is getting worse?  First rate your pain according to the scale below.  If getting worse, the pain increases in:
        • Intensity – how bad it hurts.  Pain started at a 3/10 and is now a 6/10
        • Frequency – how often it hurts.  Initially only hurt after runs, now hurts when you walk, during work or after sitting for long periods of time
        • Duration – how long it hurts.  Initially hurt only after a run for about 45 minutes.  Now it hurts for 2 days following a run.
      • Your pain is causing you to limp or altering your running gait.

    • Be Proactive - as we spoke about last couple of weeks with ice and increasing recovery methods, you can often prevent your pain from getting to this level.  Being proactive is KEY.
  • What are some holistic, diet, and/or lifestyle changes that runners can incorporate to prevent and treat runner's knee? Proactively runners can do a lot to prevent runners knee. 
    • First have a running assessment by a qualified athletic trainer, running coach or physical therapist.  Majority of runners, novice and expert, would benefit from a through running assessment.  Two traditional running assessments.
      • Video based – in this type of assessment the clinician will have you run on a treadmill while video tapping your running mechanics.  As mentioned previously, there are a lot of things we can assess with video that tells us a lot about areas of weakness, tightness and overall flaws in the running technique. When identified and corrected this will not only improve performance but decrease risk for running injuries. Couple of things for you to determine if this is right place to do your assessment.
        • Do they use an app or software based technology?  Software based is much more accurate technology.  Dartfish is the most frequently used and the gold standard in these assessments.  Use of apps is good but angles are not accurate and people tend to hold their phone to record (provides poor quality of video).
        • Do they have a standardized protocol? Is the camera secured to a tripod or stable surface.  Is there a sequence they go through with you, varying speeds of run, multiple directions.
        • Are you provided with a comprehensive report?  Some will just review the video with you.  Others will analyze the video and provide you with a comprehensive report.
      • 3D Running assessment.  We typically use a 3D wearable sensor technology that allows us to assess how you run on a treadmill and on the road.  With this technology, once your treadmill assessment is complete, we can then hook the sensors up to you and have you do a 10 mile run outside in your environment.  This allows us to see how you run on different surfaces and for a prolonged period of time.  This will provide us with data throughout that entire event and let us see where and when the system is breaking down.
        • Shoe assessment - in several of our facilities we use this technology as well to help runners choose the right shoe.  This allows the runner to try various pairs of shoes and collect biomechanical data to see what is the better shoe for them biomechanically.  This system will provide comprehensive data to allow you to make a more informed choice on what shoe is better for you.  Below is a snap shot of the data that is provided during the run.
    • Second, stay hydrated and eat a proper diet.  Nutrition and hydration have a direct impact on running biomechanics.  Athletes who are dehydrated and who put subpar fuel in the system break down faster.  Proper diet and hydration also aids in soft tissue repair.  This builds a chemical environment that is optimal for soft tissue repair.  Below is the hydration chart which will help determine your level of hydration based on the color of urine.  


    • Third, get enough sleep.  Most of the time runners knee is the result of the tissues being broken down faster than they can repair.  Getting enough sleep and REM sleep is vital for soft tissue repair and recovery.
    • Fourth, if you run a lot, consider finding a provider that provides recovery tools.  What are recovery tools?  Things like the Hypervolt, Normatec boots, Cryotherapy and dry needling.  All of these are research based methods shown in the research to aid recovery.  There are some out there that are not named here that have no basis in the science but being used a lot in recovery.  Stick with what works and what is supported in the research.  It will help you keep on the road, running pain free and continuing to enjoy a healthy life style.
    We hope you enjoyed this series.  We hope you learned something and more than anything, we hope this helps you keep on the road and injury free.  Stay tuned and please share with others you think might be interested.  #ViPerformAMI #ACLPlayItSafe


    Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment and ACL injury prevention.  He is the founder | developer of the ViPerform AMI, 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, September 3, 2018

    Preventing Runners Knee - Part IV

    Last week, we continued our discussion on how to prevent runner's knee with a discussion of the variety of diagnosis's that fall under the category of "runner's knee".  We also spoke about the first line in defense to preventing runners knee.  This week we will start off our discussion looking at stretches that can be performed to prevent runner's knee.
    • What are some exercises and/or stretches people can do at home to treat runner's knee? 
      • Stretches/soft tissue mobilization – in general terms, we typically have all runners work on mobility of the entire lower kinetic chain.  This would include the following stretches/mobility movements which we perform with a vibrating foam roller (Hyperice).  Key is to make sure you are not just “smashing” the tissue but providing a good stretch while providing comfortable pressure.  Use of the vibrating roller facilitates greater relaxation of the muscle and more comfortable stretch through greater ranges of motion.  This aids in recovery following a hard run.  We typically have runners do this on their non-running days or to help recovery following a hard run.  Typically we will spend a good 15-20 minutes on these recovery exercises.  
        • ITBand - Start by lying on the vibrating roller in the position indicated.  Slowly roll the foam roller from the TFL (from the crest at the hip) down along the ITband to the knee.  At the same time, move the leg in an adducted position while bringing the hip toward the floor. 


        • Hip flexor/quad – Start by lying on the vibrating roller in the prone position, keeping your abs tight, roll the foam roller from the anterior hip down along the quad.  You can increase the stretch to the quad by flexing the knee during the motion.


        • Hamstring/Glut – lying in a long sit position, roll the foam roller from the glut along the entire length of the hamstring.  To facilitate hamstring stretch, keeping your knee straight, abs tight, bring your butt to the ground and slowly flex forward while keeping your chest up.   
        • Calf – Sitting in the long sit position with your knee straight, roll the foam roller from the back of the knee to the Achilles tendon.  To facilitate the stretch, as you roll down the calf, slowly dorsiflex (bring your foot up) while keeping your knee straight.


        • Soft tissue mobilization - In addition to the above, we have also found another great tool to aid in recovery that is relatively inexpensive.  The Hypervolt is a percussion gun that we use primarily for soft tissue mobilization and will even use in combination with stretches.  This tool has some solid science behind it and you are now finding this in most athletic training rooms in professional sports.  I find a lot of athletes get some great relief especially when working our muscle soreness from a previous training session.  


        • Pre-Run Routine - In addition to these stretches, we also have runners do the Run Safe pre-run routine prior to each run.  These dynamic stretches aid in creating the level of mobility needed for a run in addition to providing a warm up to the neuromuscular system for providing stability through full range of motion.
    • What are some recommendations you have for runner's if they want to prevent runner's knee, something they can do at home?  The Run Safe program is specifically designed to address the biomechanical issues that result in runner’s knee.  This free app has videos for every exercise and has both a pre-run routine as well as a post run routine.  
      • Pre-run routine - prepares the runner by taking the lower kinetic chain through full functional range of motion all while maintaining stability.  This routine takes 5 minutes to implement and serves a warm up for running.  
      • Post run routine - is done immediately after the run.  This fatigue state training has better carry over to improving a runner’s biomechanics when it matters the most, when they are tired.  These exercises focus on single limb stability, proprioception, glut strengthening and core strengthening.  
      • The Run Safe program - has 4 levels of progression so that as the athlete masters one level, they can move onto the next.  This way they can continue to progress their strengthening program, constantly driving improvement in biomechanics and athletic performance.  This program has not only been shown to reduce injuries in runners but also shown to improve sprint speed and endurance.   


    We hope you are enjoying this series.  Next week we will wrap up our discussion on runners knee.  Stay tuned and please share with others you think might be interested.  #ViPerformAMI #ACLPlayItSafe


    Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment and ACL injury prevention.  He is the founder | developer of the ViPerform AMI, 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.