Monday, September 14, 2020

2020 Sports Season: Proceed With Caution - A Clinical Commentary

As a sports medicine physical therapist, I have been blessed to work with high school, collegiate and professional athletes for 24+ years.  As most of you know, I have devoted the majority of my professional career to a calling.  The calling of prevention.  Although it started in ACL prevention, it has expanded to all preventable lower limb injuries.  This started over 20 years ago and is a part of what I do every hour, every day.  With the commercial launch of the DorsaVi ViPerform AMI (athletic movement index), adoption in professional, collegiate and sports rehabilitation, this has allowed access to a level of data that previously was unobtainable in our industry.  With this work and associated research, this has afforded me the opportunity to travel and work with the industries best orthopedic surgeons, physical therapists and athletic trainers in the US.

COVID-19 has impacted all our lives in ways we may not full realize yet.  One thing that happened across the US, was that there were 10s of thousands of athletes who had ACL reconstructions (ACLR) who were no longer able to continue with their one on one physical therapy.  Most had access to their therapists via telehealth.  As good as that may be, it is never as good as one on one physical therapy.  For some athletes, this was only a minor inconvenience lasting only a couple of weeks.  However, for 1000s of our athletes, this meant months of no one on one therapy.  These athletes had to rely on what their PT could see over the computer, instruct over the computer and the hope that the athlete continued with their individualized program correctly.  One of the things we do prior to returning an athlete to sport is we run them through a series of tests (ViPerform AMI).  This test measures how stable the athlete is through a series of sport related movements.  This gives us a good indication on whether or not the athlete is physically ready for the rigorous demands of sports and stable enough to not stress their reconstructed ACL.  

For definition purposes, I am going to refer post-COVID.  What I mean is athletes who have been undergoing rehab via telehealth and not had traditional regular pre-COVID PT.  This DOES not refer to athletes who have had COVID.  Having defined that, if we compare our athletes who have been tested at 6 months, 9 months and 12 months post ACLR pre-COVID to those who we testing now post COVID, we see an alarming drastic difference.  Those athletes who we are testing post COVID have much greater quadriceps deficit, much less control of dynamic valgus in single limb performance, much greater speeds of valgus in single limb testing and less pelvic and core control.  These athletes, on the average, are 3-4 months behind what we see in pre-COVID test results.  This is extremely alarming since these athletes think they are at 6 or 9 months post ACL when in reality, they are functionally where they are typically at when at the 3 to 6 months post op mark.  

I don't ever preach what someone should do but as a parent of an athlete and someone who functions in this area 24/7, if my child had an ACLR and their rehab was done during COVID-19, I would seriously consider taking a season off to prepare for next season.  Statistics for re-injury with return to sport are not great.  Mark my words, this year, it will be 2 to 3 times what it has been in the past.  In addition to the ACLR athlete, we also have a high incidence of ACL injuries in athletics in the US during a normal season.  This year, we are starting seasons with 1/2 of the normal conditioning time coming off an unprecedented time in our history when athletes did NOT have access to training facilities.  For 80-90% of athletes, this means they are going into a season in a deconditioned state.  One thing that the research is very clear on is if you take a deconditioned athlete into a normal sports season with normal preseason conditioning, the likelihood of injury is high.  Now you shorten the pre-season conditioning and you compound that problem even more.  

I don't say this to discourage athletics this season.  I say this to encourage us to think through what this should look like on an athlete by athlete basis.  I, as well as many of the leading experts in sports medicine, have a great fear of the injuries we will see this year.  We think we are about to see an unprecedented number of ACL injuries and concussion.  That is why I am devoting the next two series to The Dreaded ACL Injury and Concussion.  I will put screenings you can do with your athlete as well as some exercises to improve performance.  For those looking to get their athlete assessed, there are over 400 providers across the US using the Viperform AMI.  Feel free to DM on instagram @bjjpt_ACL_guy or twitter @ ACL_prevention.  I hope you enjoy this series, God Bless and keep safe.

 

Dr. Nessler is a practicing physical therapist with over 23 years sports medicine clinical experience.  He is a nationally recognized expert in the area of athletic movement assessment and injury prevention.  He is the founder | developer of the ViPerform AMI,  ViPerform AMI RTPlay, the ACL Play It Safe Program, Run Safe Program, author of a college textbook on this subject and published researcher.  Trent has performed >5000 athletic movement assessments in the US and abroad.  He is the President of Rebound Vitality providing injury prevention services for the tactical athlete and movement consultant for numerous colleges and professional teams.  Trent also a Brazilian Jiu Jitsu purple belt and complete BJJ/MMA junkie. 

 

 

Monday, September 7, 2020

One hour Q&A with Dr. Nessler - Part III

Last couple of weeks I started this series in an effort to give back to my faithful viewers, I decided to try something a little different for this series where I broke down a one hour Q&A into small 2-3 minute snippets.  This will be the last in this series.  I hope you enjoy and if this is something you would like to see more of or some specific questions, please message me on either instagram or twitter (both below) and I am happy to address.

Question 7: How does movement impact all lower kinetic chain injuries?




Question 8: How much room do you need to perform a comprehensive assessment?





Question 9: What research do you cite when talking to MDs about movement assessment?




Question 10: How long does it take to perform a comprehensive assessment and is technology like this affordable?


As always, I appreciate all our followers and hope you find the information we provide useful in your practice with your athletes.  If you do, please follow me on instragram @bjjpt_acl_guy and Twitter @acl_prevention.  I also just launched a new website, www.drtrentnessler.com.  My vision is to create a movement revolution in the world of ACL rehab.  Check it out, hear more about my story and where we are headed.  Train hard and stay well.  #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,  ViPerform AMI RTPlay, 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 and movement consultant for numerous colleges and professional teams.  Trent also a Brazilian Jiu Jitsu purple belt and complete BJJ/MMA junkie. 

Monday, August 31, 2020

One hour Q&A with Dr. Nessler - Part II

Last week I started this series in an effort to give back to my faithful viewers, I decided to try something a little different for this series where I broke down a one hour Q&A into small 2-3 minute snippets.  I hope you enjoy and if this is something you would like to see more of or some specific questions, please message me on either instagram or twitter (both below) and I am happy to address.

Question 4: Is there an ROI for the patient and the practice with technology like this?




Question 5: How does concussion impact lower kinetic chain injuries?




Question 6: Why do you use wearable sensor technology?



I hope you found this information valuable.  Next week, we will have the next three Q&A from the webinar.  As always, I appreciate all our followers and hope you find the information we provide useful in your practice with your athletes.  If you do, please follow me on instragram @bjjpt_acl_guy and Twitter @acl_prevention.  I also just launched a new website, www.drtrentnessler.com.  My vision is to create a movement revolution in the world of ACL rehab.  Check it out, hear more about my story and where we are headed.  Train hard and stay well.  #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,  ViPerform AMI RTPlay, 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 and movement consultant for numerous colleges and professional teams.  Trent also a Brazilian Jiu Jitsu purple belt and complete BJJ/MMA junkie. 

Monday, August 24, 2020

One hour Q&A with Dr. Nessler

Over the last 15+ years I have had the pleasure of divulging into one of my true passions.  Teaching.  I initially started teaching for MDs, DCs, PTs, ATCs and strength coaches back in 1997.  Since then, I have been blessed to teach all over the US and abroad.  I love sharing the passion for what we do, how we do it and what we are learning.  Last year alone, I was blessed to teach at 35+ conferences in the US.  Since COVID-19, this has led to an entirely new way of teaching for me, virtually.  Although I fully anticipated this to be the year that I did a lot less teaching, it has actually turned out to be one of the busiest teaching years yet.  

This blog was initially started as a way to provide the athletes I treated with an avenue to get reliable evidence based information.  However, it has expanded to be much more than that.  Today, we get over 100 views a day and majority of these are professionals looking for evidence based information.  I am honored you would come here for that.  You have no idea how seriously I take that.  Over the five history of this blog, I have never done a video Q&A.  Recently, however, I was afforded the opportunity to take live Q&A about movement, what we are learning and how we can apply this to our practice.  

In an effort to give back to my faithful viewers, I decided to try something a little different for this series.  I have broken this one hour Q&A into small 2-3 minute snippets.  I hope you enjoy and if this is something you would like to see more of or some specific questions, please message me on either instagram or twitter (both below) and I am happy to address.

Question 1: What was the inspiration to start looking at movement at the depth you do for the last 20 years?



Question 2: How did you choose the movements that you look at and why?



Question 3: How are you evaluating movement for making more informed return to play decisions?




I hope you found this information valuable.  Next week, we will have the next three Q&A from the webinar.  As always, I appreciate all our followers and hope you find the information we provide useful in your practice with your athletes.  If you do, please follow me on instragram @bjjpt_acl_guy and Twitter @acl_prevention.  I also just launched a new website, www.drtrentnessler.com.  My vision is to create a movement revolution in the world of ACL rehab.  Check it out, hear more about my story and where we are headed.  Train hard and stay well.  #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,  ViPerform AMI RTPlay, 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 and movement consultant for numerous colleges and professional teams.  Trent also a Brazilian Jiu Jitsu purple belt and complete BJJ/MMA junkie. 

Monday, August 17, 2020

Poor Movement = Decreased Athletic Performance - Part IV

Last week we concluded this discussion looking at the impact that pathokinematics has on flexibility.  This week, we will conclude this series by looking at the impact pathokinematics has on balance.
 
Balance and Lower Extremity Control

Balance is physical equilibrium or the ability to maintain stability produced by even distribution of weight on each side of a vertical axis.  In humans, there are three factors that influence balance.  These are:

·       The Vestibular System:  complex mechanism in the inner ear that controls balance by monitoring the position of your head.

·       The Visual System:  uses input from your eyes to detect changes in the floor surface.

·       The Somatosensory/Proprioception System:  Uses sensory input from your lower extremities to give your brain feedback about the body’s relationship to the floor.

Some authors argue that there is a fourth component that influences balance which is a psychological component:  the fear of falling.  For our purposes and for the athletic population, we will address only the three factors listed above.  Of those factors, pathokinematics has the largest influence on the somatosensory system or proprioception.  So prior to talking about the impact pathokinematics has on the somatosensory system or proprioception, we must first define proprioception. 

Proprioception is the sense of the relative position of neighboring parts of the body, joint position and the strength of effort being employed during movement.  This complex sense is provided by multiple systems (Neuroscience, 2nd edition, by Purves et al. 2001) including the inner ear (bony labyrinth) and sensory receptors in the joint capsule, in the musculotendinous junction (golgi tendon organ) and within the muscle (muscle spindle).  Stimulation of these systems contributes to our sense of awareness of where our body is in space.  Several factors that can negatively impact this input are injury, pain and/or abnormal movements (bad technique) performed over time.  With regard to this last factor, we need to remember that poor movement patterns repeated over time result in repetitive stimulation of these systems in these altered positions.  This, in a sense, “teaches” the fibers that this is the “correct movement or posture” when in fact, it is not.

The same is true with pathokinematics over time.  The body becomes accustomed to moving in this way, and the athlete senses that this is normal movement---it “feels” right.  Again, let’s use the example of the athlete above who squats with the obvious lateral shift.  Because he has trained his body over the span of months to squat in this way (or he has allowed himself, knowingly or unknowingly, to squat in this way) his body perceives this as “normal.”  When moved into a more anatomically correct movement pattern, he feels awkward, weak and perceives the positions and motions as abnormal.  This is due in part to the proprioceptors in his lower extremity.  They must be re-trained to sense this “new” position as correct relative to space.

So, let’s examine this concept in more depth as it relates to performance by looking at proprioception or balance in the core and hip (marked in red in the photograph).  A decrease in proprioception and balance in the core and hip can lead to many performance limitations, and we see this especially in many of our female athletes.  Such a deficiency in proprioception can present itself in the form of an inability of the athlete to disassociate lumbar spine motion from hip motion, as in the example of lumbopelvic disassociation.  Also if one has weak hips, particularly in the stabilizing muscles of the hip such as the gluteus medius and other smaller and/or deeper stabilizers, (gluteus minimus, gemelli, obturators, tensor fasciae latae, quadratus femoris), we might expect to see a reduction in the ability of the athlete to balance, especially during single limb activities.    

In an unpublished 2009 study, a group of examiners assessed 3 different movement screens commonly used in sports medicine and implemented these during collegiate and high school physicals over the span of 3 years.  Subjects consisted of 600 male and female athletes ranging in age of 15 years old to 20 years old.  One of screens used during this study was the Star Excursion Balance Test.  One of the key movements being assessed during this test by examiners was posterior medial movement (shown above).  This motion requires a significant amount of proprioception in the hip as well as gluteus medius strength in order to stabilize the knee in a closed kinetic chain situation like this one.  Male athletes performed favorably on this movement with 80% of subjects able to perform the test to within 10 cm of the contralateral limb.  Female athletes performed less favorably, with less than 55% of subjects able to perform the test to within 10 cm of the contralateral limb.  Most examiners noted that females would first lose control at the hip and fall into a trendelenburg (versus pronating at the foot first) which would be followed by loss of control at the knee which would lead to the knee moving into a valgus position. 

One of the questions one might ask at this point is whether or not it is the pathokinematics that lead to significant reductions in balance and lower extremity control over time or is it the reductions in balance and lower extremity control that lead to pathokinematics?  Again, it is the question of the egg before the chicken or the chicken before the egg.  Although we don’t know the answer to this question, we do know is that both present together in a majority of cases and if we improve proprioception, then we also see a corresponding improvement in pathokinematics.  And, of course improved balance, body control and movement all lead to athletic performance improvement and reduction in injuries.

Reaction Time

The last performance related area we would like to address that is directly affected by pathokinematics is reaction time.  Before we discuss the impact of pathokinematics on reaction time, let’s review some basic concepts on reaction time.  Reaction time, in the most simplistic terms, is a combination of:

1.     Perception time – time from which the athlete senses the need for movement (my opponent is moving to the right) to the time the athlete chooses the appropriate response (response selection – I need to cut to the left).  This is often referred to as processing time as it is the time that it takes for the person to sense a stimulus, the brain to process it and then select the appropriate movement.  This requires visual input, the processing of that input in the higher centers of the brain, and then a selection of the appropriate motor program (in the primary motor cortex).  There are a lot of factors that impact perception time or processing time[vii].  These include but are not limited to:

a.     Mental alertness
b.     Mental rehearsal
c.     Age
d.     Vision
e.     Distraction level
f.      Fatigue

2.     Movement time – once the response is selected, movement time is the time that it takes the athlete to execute the required movement.  There are a lot of factors that impact movement time.  These include but are not limited to:

a.     Age
b.     Gender
c.     Fatigue
d.     Exercise
e.     Stimulus drugs
f.      Illness

Understanding the components of reaction time and the factors which positively or negatively impact reaction time gives us a better understanding of how pathokinematics can play a role in limiting performance by increasing reaction time.  For example, if an athlete demonstrates significant pathokinematics resulting in altered length tension relationships, decreased efficiency of movement, poor proprioception, and decreased endurance, then one can easily see how reaction time would be negatively impacted.  This is especially true and more evident in later phases of the game when an athlete’s pathokinematics may become more pronounced and the efficiency of the system becomes compromised to an even greater degree due to fatigue and other contributing factors. 

In sports in which speed and explosive movements are important, reaction times are imperative to overall athletic performance.  Improvement of factors that result in decreased efficiency throughout the system and the resulting efficient transfer of energy across that system, can and will result in the reduction of time from initiation of a given movement to full execution of that movement[viii].  By improving the strength and endurance of the entire kinetic chain, we can capture, conduct and channel all available power generated by the athlete more effectively and efficiently, and by improving this energy transfer, we thus improve performance.

Reaction time, like all of the other sports performance fundamentals discussed in this chapter, including pain and pain prevention, efficiency, energy conservation, endurance, power, speed, flexibility, balance and lower extremity control, has a direct correlation to pathokinematics.  In addition, it’s important to note that each of these performance considerations is affected by the others.  This results in a powerful compounding effect when any one or more is present.  In other words, when pathokinematics lead to a deficit in any one of these or any other sports performance area, all other areas are affected as well.

I hope you found this information valuable.  As always, I appreciate all our followers and hope you find the information we provide useful in your practice with your athletes.  If you do, please follow me on instragram @bjjpt_acl_guy and Twitter @acl_prevention.  I also just launched a new website, www.drtrentnessler.com.  My vision is to create a movement revolution in the world of ACL rehab.  Check it out, hear more about my story and where we are headed.  Train hard and stay well.  #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,  ViPerform AMI RTPlay, 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 and movement consultant for numerous colleges and professional teams.  Trent also a Brazilian Jiu Jitsu purple belt and complete BJJ/MMA junkie. 

Monday, August 10, 2020

Poor Movement = Decreased Athletic Performance - Part III

Last week we began to discuss the impact that poor movement has on athletic performance.  We concluded our discussion by looking at the impact that poor movement (pathokinematics) has on power generation.  We continue that discussion looking at the impact on power.

In addition to increasing the amount of force that can be produced by a muscle or muscle group, when we improve length/tension relationships, we also increase the efficiency of movement.  With an increase in efficiency in movement comes decreased time to produce the movement, as well as an increase in the force that is able to be generated.  Without any change at all to cardiovascular output, efficiency and endurance, if we simply increase the ability of the muscle to produce more force with less energy demand, in a shorter period of time, not only does power in the pure sense increase, but overall endurance improves as well. 

There are a lot of standardized tests to assess muscular power in athletics but the two most commonly used are the Sargent Jump Test and the Stair Sprint Test.  The Sargent Jump Test was developed by Harvard’s gymnastic coach, Dudley Sargent in the early 1900s and it is still used today as an assessment of power output and maximal vertical height (it is also known as the Vertical Jump Test).  There are some variations to the test.  But in the most basic form, the athlete stands next to a wall sideways, reaches up with the arm closest to the wall fully extended, keeping the feet flat on the floor, and the highest point at which the fingers tips reach up on the wall is marked.  Then the athlete performs a maximal vertical jump marking the point at which the finger tips reach at the peak of the jump.  This is performed 3 times and the average of the three is calculated.

The Stair Sprint Test has been found to be highly reliable and valid for measuring explosive power and is endorsed by the American College of Sports Medicine.  In this test, the athlete is timed while sprinting a given distance on ascending stairs.  The force is the athlete’s weight and the time is how long it takes to ascend the given distance.  In this particular test, the athlete improves, i.e., increases his or her power output, by decreasing the time it takes to ascend the stairs.

It is easy to see the effect that movement patterns would have on the Stair Sprint Test when we look at another example.  Using the Step Up Test to assess an athlete’s movement pattern, we can see that when this particular athlete ascends (steps up) the right hip falls into an adducted position and the right femur rotates internally.  When this occurs, two things happen:  First, there is an immediate loss of energy in the kinetic chain.  Second, these changes in the stepping up action alter the length/tension relationships in the lower body.  Since this test is designed to demonstrate efficiency of movement (or lack thereof) and a corresponding maximal use of energy, each of these occurrences has a dramatic impact on power output.  In the position in which we see this athlete, the muscles cannot contract maximally and much of the explosive power she needs to climb the stair is lost.  Test results show a longer length of time to complete the task or movement as a result. 

In sports, speed and power are sometimes used interchangeably.  Speed is defined as distance traveled per unit of time.  From a calculation standpoint, the only difference between a speed calculation and a power calculation is that the power calculation takes the athlete’s weight into account, or the weight of an object that is being moved by the athlete.   We can easily see then the impact that abnormal movement or pathokinematics has on power.  Therefore we can deduce that pathokinematics in this, or any, athlete would similarly impact speed due to the loss of energy in the kinetic chain and the inability of the muscles to contract maximally and generate the greatest amount of explosive power in the shortest amount of time.

Flexibility

Flexibility is simply the ability to move your muscles through their full range of motion.  Factors that influence flexibility include:

·       Heredity
·       Age
·       Gender
·       Mode/level of activity
·       Internal tissue temperature
·       History of injury (scar tissue, altered bony structure)
·       Pain

Since the late 80’s or early 90’s there has not been much research conducted on factors that influence flexibility or how we can influence flexibility with training.  Even so, in a clinical and athletic training setting we do see the impact that pathokinematic movement patterns have on flexibility.  If, for example, an athlete has a significant lateral shift with a squat, then this movement pattern is going to be carried over to every squatting motion he performs, outside of sports and during sports.  This includes such activities of daily living as sitting down on a chair, sitting on his bed, sitting and rising from the commode, and getting in and out of a car.  As a result of imbalances in the body during this movement alone, overall flexibility will be greatly affected, which of course translates to performance.  We know that flexibility is critical for all sports and many athletic trainers, coaches and other professionals who work in the field of athletics believe that for the total time spent, flexibility training may in fact be the most important and the most beneficial activity across all sports.

Looking at one of our previous examples, we can easily see how pathokinematic movement can increase tightness in the body from the core down, reduce flexibility and contribute to an ever increasing reduction in performance.  This athlete, performing the squat test, is clearly shifting to the right, as shown previously.  He is also unable to keep his back in alignment while bearing most of his weight on the right side.  This shift is lengthening the hamstring and the quadriceps on the left and shortening them on the right, as shown.  This means that over time, he is likely to become less flexible on the right side of his body than he is on the left.  This further reinforces the shift, making it worse over time in a vicious cycle.  In addition, due to this particular abnormal movement and the associated inflexibility and abnormal force attenuation it causes in the lower kinetic chain, it is likely that this athlete will also become much less flexible in the lumbar spine, and eventually also in the thoracic and cervical spine.  This can lead to imbalances in running gait, excess (and inefficient, energy zapping) motion in the hips, pain in the L5/S1 region of the lower back, pain traveling up the back into the mid and upper back and neck, and compromised power output through the transmitting core. 

A couple of last points related to flexibility in this example that are worth noting is first that as a part of his abnormal movement or pathokinematics, this athlete’s arms move forward as he squats.  He does this as a compensatory strategy in order to prevent himself from falling over.  So, not only is his inflexibility adding to abnormal force attenuation, it also adds to a loss of balance as well.   Again, this further increases the loss of kinetic energy and ultimately decreases the efficiency of the entire system.  Over time, this athlete is likely to become more and more inflexible in the hip flexor group as well, which is critical for football and other activities of daily living such as walking and running as discussed above.  These factors related to flexibility can ultimately lead to other kinds of injuries and pain with activity down the line.  Of course we can also easily see the performance impact limited mobility has on speed, power and endurance on the football field.

I hope you found this information valuable.  Next week, we will continue our discussion on how movement can impact balance and control.  As always, I appreciate all our followers and hope you find the information we provide useful in your practice with your athletes.  If you do, please follow me on instragram @bjjpt_acl_guy and Twitter @acl_prevention.  I also just launched a new website, www.drtrentnessler.com.  My vision is to create a movement revolution in the world of ACL rehab.  Check it out, hear more about my story and where we are headed.  Train hard and stay well.  #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,  ViPerform AMI RTPlay, 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 and movement consultant for numerous colleges and professional teams.  Trent also a Brazilian Jiu Jitsu purple belt and complete BJJ/MMA junkie. 

Monday, August 3, 2020

Poor Movement = Decreased Athletic Performance - Part II

Last week we introduced the concept that poor movement (pathokinematics) negatively impacts athletic performance.  We will continue that discussion looking at the impact that pathokinematics has on movement efficiency and energy.

Efficiency, Energy Conservation and Endurance

Another way that pathokinematics, or movement that falls outside the norm can impact performance is by increasing the amount of energy required to move the body in order to perform the function or participate in the sport.  If the system is working properly, the limbs are controlled easily and efficiently and the least amount of energy is used to move the body---to walk or run.  However, simple tightness or weakness in any part of the body can have a dramatic effect on the quality and efficiency of movement and therefore the energy required to move a certain distance within a certain amount of time.  This is often seen when there is hip flexor tightness.  During the running cycle, one of two things happens.  They shorten their stride length to compensate for the tightness (makes running less efficient) or they rotate in their lumbar spine to make up for the lost motion (which can lead to low back pain).

Of course if natural stride length is shortened, as in the walking/running example, it also takes more steps to travel the same distance, and consequently more energy.  This lost energy cannot then be used to extend the time of exercise or the speed of leg turnover in running or walking.  Sometimes, only one hip flexor is tight, which can cause the stride length to be asymmetrical.  Such asymmetry also decreases the efficiency of movement, and again more energy is required to travel the same distance.  So, it is not only more difficult to move when moving the body in “unusual” ways, but it also takes longer to move the body the same distance at any given speed.  Both the increased difficulty and the increased length of time it takes to move require additional energy expenditure.

Muscular endurance is defined as the ability of a muscle or group of muscles to sustain repeated contractions against resistance for a sustained period of time.  Factors that influence endurance are:

·       VO2 Max – also known as “maximal oxygen uptake,” is a measure of the maximum ability of the body to transport and use oxygen during a specific period of time while engaged in intense exercise

·       Lactate Threshold – the exercise intensity at which lactic acid starts to accumulate in the blood stream, sometimes referred to as anaerobic threshold 

·       Exercise Economy – the efficiency of the technique (movement) the athlete has in his or her respective sport

Improvements in the first two factors come with endurance, power and cardiovascular training.  However, improvement in exercise economy (which is impacted by the quality of movement) has a direct effect on efficiency and consequently, energy conservation.  In the walking/running example above a simple improvement in stride length can result in improved efficiency of the movement and entire system, leading to less energy expenditure, which results in improved athletic endurance---in this case, the ability to run for a longer period of time before having to stop.  This is where a good running assessment and orthopedic assessment come into play.  Getting someone who knows not only how to assess your running gait but also performing a detailed orthopedic exam to see where the limitations are that may be leading to your altered running gait.  

 Power and Speed

Power is defined as the rate of work being done per unit of time.  In athletics, we calculate power equal to force over time (P = F/T) or the amount of time that it takes to move an object (a weight, sled, bike or your body weight) a given distance.  Power can be increased by either increasing the amount of force applied or by reducing the amount of time it takes to move the object.  So, improvement in power output can be influenced in two ways: increasing force or decreasing time.

Pathokinematics have just as big, or perhaps an even bigger relationship to power output than pain, efficiency, energy conservation and endurance.  To explain this, we must first talk about muscles and specifically, length and tension relationships.  

Muscles work in a length and tension relationship.  There are optimal lengths at which muscles produce the maximum amount of force (see the graph above).  If a muscle is in a position that is shorter or longer than this optimal position, then the strength or force that the muscle can produce is decreased.  Take for example, the bicep curl exercise.  When someone performs a bicep curl, there are stages during the motion that the exercise is more or less difficult.  Typically greater effort is required at the beginning of the curl and at the end of the curl.  Your bicep is strongest in the mid-range of the motion, and so it is at this point that the least amount of energy is required to move the weight or curl the arm upward.  It is at this point that the tension the muscle is able to produce is at its highest, relative to its length, and therefore this is the optimal range of motion in which the bicep can produce the most force. 

This same concept carries over to all other body movement.  Abnormal movement patterns or pathokinematics move the body, including all its joints, ligaments, tendons and muscles outside the “optimal” range.  Length/tension relationships in the muscles are drastically altered when we move abnormally and consequently, less force can be produced by the muscles.  To illustrate this point, let’s take a look at the following example. 

The young man in this photo is a football player who is having difficulty performing in his sport following an injury.  Performance tests such as the vertical jump and 40 yard dash show a marked deterioration as compared to his pre-injury results.  He has been performing squats as a part of his rehabilitation and training routine in order to strengthen the injured limb and thereby improve his performance results.  However, he is having difficulty understanding why he continues to have such a large strength deficit on the left side.   When we view his squat, it is apparent to even the casual observer that there are several issues that might contribute to such a strength deficit on the left side and the resulting decrease in performance on these performance tests as well as on the football field.  

When we consider length/tension relationships, we know that if asymmetrical movement patterns like the one seen in this photograph are not corrected, none of this athlete’s muscles from the lower back down will ever be as strong as they could be, nor will they be able to produce as much power as they would in a more symmetrical movement pattern.  Part of his overall weakness is actually the result of weakness in his right side as well as his left.  The right, in this example, will always be worked more than the left due to the marked weight shift to that side, which obviously causes more of the load burden to be borne on that side.  However, because there is also a dramatic change in the length tension relationship on that side, the right side will never be as strong as it would be either if the exercise was performed correctly.  Because of the high degree of shift, his left quadriceps is put in a lengthened position while the right is in a shortened position.  His left gluteus medius and maximus are put in lengthened positions and his right in shortened positions.  So, as stated before, even though his right might be stronger, it will not be as strong as it could be until these length/tension relationships are corrected and the athlete is able to access and use the ranges in which his muscles can produce the maximum amount of force.

I hope you found this information valuable.  Next week, we will continue our discussion on how movement can impact performance on certain tests.  As always, I appreciate all our followers and hope you find the information we provide useful in your practice with your athletes.  If you do, please follow me on instragram @bjjpt_acl_guy and Twitter @acl_prevention.  I also just launched a new website, www.drtrentnessler.com.  My vision is to create a movement revolution in the world of ACL rehab.  Check it out, hear more about my story and where we are headed.  Train hard and stay well.  #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,  ViPerform AMI RTPlay, 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 and movement consultant for numerous colleges and professional teams.  Trent also a Brazilian Jiu Jitsu purple belt and complete BJJ/MMA junkie.