Adaptations and compensations.

. . . the entire system has to adapt to that deficiency. That means compensation. Now, does adding strength to that asymmetry (compensation) have a consequence. Most likely. Will it lead to injury? That is the question.

We are going to keep pounding sand on this one because we believe this is important.
All too often people are working out and strengthening their systems, and that is good. But, if they are strengthening a system that is asymmetric or strengthening a faulty pattern (clearly, as in too much arch collapse) they are likely overburdening the hierarchical system and a component of the chain of that system.
Now, many are going to argue, and we know who those folks are, they are going to argue that if the movement is not painful, if the posturing of the load is not painful, then it is not a problem. Sure, and that is easy to say, but there is no proof they are right either. And, we are not saying we are stonewalled right either, but we are trying to be logical with what we know and what some of the research says (yes, that fits our bias). But our eyes are open and we hear the arguments from the other side, but those arguments come from a crystal ball in our opinion. Truthfully, no one has that crystal ball and can see into the future to see if one side of this argument has any more "legs" to it.
However, we know that . . .

"Human movement is initiated, controlled and executed in a hierarchical system including the nervous system, muscle and tendon. If a component in the loop loses its integrity, the entire system has to adapt to that deficiency. Achilles tendon, when degenerated, exhibits lower stiffness. This local mechanical deficit may be compensated for by an alteration of motor commands from the CNS. These modulations in motor commands from the CNS may lead to altered activation of the agonist, synergist and antagonist muscles."- Chang and Kulig

So, when we see a pattern of loading that is aberrant, and especially when it is most likely playing into a client's painful presentation, it is an easier sell on the thought-arguments above. We know that the entire system has to adapt to deficiencies. It is how we are synergistically built. We have redundancies build into us that protect us. Compensation is part of the redundancy. So, does adding strength to that asymmetry (compensation) have a consequence? Most likely it does, in our opinion. Why allow an area to undergo more loading than we know it should, (ie. valgus knee loading) even if it is non-painful to a client ? Will it lead to eventual injury or pain? That is the question. But we have picked our side of the story, for now, until proven otherwise, and we work from that side of the line. For now.

"yet" is a powerful looming word.
When adding strength takes someones pain away, it doesn't mean you fixed them. It likely means you helped them adapt and protect and better negotiate the loads. However, it also does not mean that your instruction did not build a layer of initial protective strength that will not have a cost further down the road because it wasn't the right medicine for the problem.
When your cars alignment is off, and it is pulling the car to the right towards the ditch, pulling harder to the left on the steering wheel keeps the alignment aberrancy, and the ditch at bay. But nothing was fixed. You adapted and compensated. The problem is still sitting there. And you will get used to the adapted and compensated pattern of steering wheel pull in time. Until the next thing occurs. Maybe the tire will start to chirp in time, the treads silently wear unevenly, and maybe it will be your left shoulder that chirps at you, and not the car.

The squeaky wheel may get the grease, but the misaligned tire is ignored.

Shawn and Ivo, the gait guys

J Physiol. 2015 Aug 1; 593(Pt 15): 3373–3387.
Published online 2015 Jun 30. doi: 10.1113/JP270220
The neuromechanical adaptations to Achilles tendinosis
Yu-Jen Chang and Kornelia Kulig

#gait, #thegaitguys, #gaitcompensations, #gaitproblems, #compensations, #running, #walking, #genuvalgus, #pronation, #CNS, #synergist

Adding strength to compensations and asymmetry.

FootNotes, with The Gait Guys.

The CNS runs the show. Compensations are real, they are a calculated response, they are meaningful adaptive protective behaviors. Adding strength to a compensation makes them even more real, plastic, permanent. Fix the problem. Adding random strength is juvenile thinking. Letting one's client load/train/lift when in pain is juvenile (read below). Once we realize adding load to the problem can be helpful or hurtful, we are on the right path, we are winning. But it takes a deep understanding of how to add load safely, wisely, so that our client can benefit. We must try to understand adaptive behaviors, we must try to understand why our client's CNS made the choices it did.
Now, imagine a client with ankle pain, and resultant ankle dorsiflexion/ankle rocker loss. Now, imagine what their gait will look like as well with that premature heel rise and everything that adapts from that premature heel rise. Now, read below and understand one way how the CNS adapts. Why? So that the next time one chooses a stretch, mob, flossing, etc to gain a range of motion, without any additional meaningful measures, hopefully they will realize they are likely not addressing the deeper problem. Pushing a range of motion is not the same as safely re-earning a range of motion. Far from it. -Dr. Allen

*Effect of Achilles tendinosis on the agonist, synergist and antagonist muscles. Chang and Kulig

"In addition to the altered control system, the present study also observed an adaptive behaviour, as illustrated by the activity of agonist, synergist and antagonist muscles. This was seen during single-legged hopping, where the contribution from the triceps surae muscle to the plantar flexors was decreased and the co-contraction from the tibialis anterior muscle was also decreased on the involved side in individuals with Achilles tendinosis. This may be attributed to the protective mechanism shielding the already injured tendon from further injury or even rupture (Lund et al. 1991)."- Chang and Kulig

J Physiol. 2015 Aug 1; 593(Pt 15): 3373–3387.
Published online 2015 Jun 30. doi: [10.1113/JP270220]
PMCID: PMC4553058
PMID: 26046962
The neuromechanical adaptations to Achilles tendinosis
Yu-Jen Chang and Kornelia Kulig

Endurance and Injuries

S.E.S. , in that order.
We have been preaching this mnemonic for a decade now here at TGG. Skill first, then endurance, then strength. In other words, first move correctly/well, then move often (build a robust amount of endurance on that skill that you can maintain it throughout your activity without losing the skilled movement without fatiguing), then add strength to this patterned movement. Then rinse and repeat; add a higher skill, add endurance, add strength. Rinse repeat.
We tell this one to our athletes, distance runners in particular, because it is no surprise that most injuries come in the later miles, when fatigue sets in, and compensations have to make up the difference if the run continues. This is necessary and protective, but the wise choice is to never exceed the fatigue, but always be inching the endurance forward.
The question is, do you know where your risk threshold lives ? When are you moving the safety meter past the safe zone and into the risk zone ? Your tightness or pain, if you are lucky, and paying attention, may be your "check engine light" moment, again, if you are paying attention. Never dismiss the benefit of a 2 minute walk in the later part of a long run when a symptom creeps in, it just might get you enough recovery to push out that last 3-4 miles with the symptoms shut down again. If you are lucky. Listen to your body, it is your job.

From the study below:
"In conclusion, NOVICE runners showed larger kinematic adjustments when exhausted than COMPETITIVE (distance) runners. This may affect their running performance and should be taken into account when assessing a runner's injury risk."

-Shawn Allen, one of the gait guys

Reference:     https://www.ncbi.nlm.nih.gov/pubmed/28730917

Sports Biomech. 2017 Jul 21:1-11. doi: 10.1080/14763141.2017.1347193. [Epub ahead of print] Novice runners show greater changes in kinematics with fatigue compared with competitive runners. Maas E1, De Bie J1, Vanfleteren R1, Hoogkamer W2, Vanwanseele B1.

Fatigue and muscle activation.

"Increased muscle activation with decreased movement in a fatigued state may represent an effort to increase trunk stiffness to protect lumbo-pelvic-hip structures from overload"

No rocket science here . . . but good to remember that fatigue sets us all up for injury if one does not observe and listen to the signs of fatigue . . . . especially when athletic and loading demand is increasing rather than tapering at the same time as the fatigue is building. As we fatigue, compensation recruitment is supposed to generate more stiffness to protect the motor units. But, can this be at a cost ?

This study looked at whether fatigue may affect muscle recruitment, active muscle stiffness and trunk kinematics, compromising trunk stability. The purpose of this study was to compare trunk muscle activation patterns, and trunk and lower extremity kinematics during walking gait before and after exercise.

The study used surface EMG to look at the rectus abdominis, external oblique, erector spinae, gluteus medius, vastus lateralis, and vastus medialis in a group of otherwise healthy individuals.

Essentially the study concluded that:
"There was less trunk and hip rotation from initial contact to midstance after exercise. Neuromuscular fatigue significantly influenced the activation patterns of superficial musculature and kinematics of the lumbo-pelvic-hip complex during walking. 
."

Gait Posture. 2016 Nov 9;52:15-21. doi: 10.1016/j.gaitpost.2016.11.016. [Epub ahead of print]

Muscle activation patterns of the lumbo-pelvic-hip complex during walking gait before and after exercise.

Chang M1, Slater LV2, Corbett RO1, Hart JM1, Hertel J1.

https://www.ncbi.nlm.nih.gov/pubmed/27846435

Where your gait might break down.

Gait appears most robust to weakness of hip and knee extensors, which can tolerate weakness well and without a substantial increase in muscle stress. In contrast, gait is most sensitive to weakness of plantarflexors, hip abductors, and hip flexors. - van der Krogt

In the past few weeks I have shared my thoughts on some articles regarding low back paraspinal musculature fatigue and the subsequent effects on motorneuron pools, specifically excitability of the soleus and quadriceps. These shared thoughts are from recent papers in the literature (search the blog over the last week). These effects are suggested to indicate a postural response to preserve lower limb function. In other words, as paraspinal fatigue set in, lower extremity muscle compensation ramped up to sustain postural locomotion demands.  Obviously, one should think this a step further and translate it all into questions of assessment of ankle dorsiflexion (ankle rocker) and control of progressing knee and hip flexion when pertaining to these muscles. The issues of stability and mobility should heighten. The one big problem in these studies, and you have even likely had these thoughts during your clinical examinations, is that one cannot truly fatigue one muscle group alone especially during activity, nor can one assess a single muscle group during manual testing. Luckily we have EMG testing capabilities in this day and age and we can more easily look into the function and reaction of a muscle and its’ direct response reactions. 

Today I have an article by van der Krogt that we read long ago, but that which one of our readers brought back into our wheelhouse.  This is pretty amazing stuff.

“This study examines the extent to which lower limb muscles can be weakened before normal walking is affected. We developed muscle-driven simulations of normal walking and then progressively weakened all major muscle groups, one at the time and simultaneously, to evaluate how much weakness could be tolerated before execution of normal gait became impossible. We further examined the compensations that arose as a result of weakening muscles. Our simulations revealed that normal walking is remarkably robust to weakness of some muscles but sensitive to weakness of others. Gait appears most robust to weakness of hip and knee extensors, which can tolerate weakness well and without a substantial increase in muscle stress. In contrast, gait is most sensitive to weakness of plantarflexors, hip abductors, and hip flexors. Weakness of individual muscles results in increased activation of the weak muscle, and in compensatory activation of other muscles. These compensations are generally inefficient, and generate unbalanced joint moments that require compensatory activation in yet other muscles. As a result, total muscle activation increases with weakness as does the cost of walking.“-van der Krogt

So, if your client comes in with knee, hip or ankle pain and a history of low back pain, you might want to pull out these articles. You may want to consider which muscles are, according to this article, most robust and sensitive to weakness. Remember what I mentioned when i reviewed the soleus article ? I mentioned that the reduced ankle dorsiflexion range may be from a soleus muscle postural compensation reaction to low back pain. Today’s article seemed to confirm that this muscle group is sensitive to weakness. In today’s discussion, not only is the impairment of the hip ranges of motion or control of the knee (from quadriceps adaptive compensation) possibly related to low back pain, in this case, paraspinal fatigue but it may be a muscle group robust to weakness which is a darn good thing when the paraspinals go to nap.

Sometimes the problem is from the bottom up, sometimes it is from the top down. It is what makes this game so challenging and mind numbing at times. If this is all too much for you, in teasing out this quagmire of a system, just throw corrective exercises at your client and hope for the best. What is the worst that can happen if you get it wrong ? Stronger compensations on already present compensations … . . why not, it is good for return business (insert sarcasm emoticon).  But, lets be honest, if it was easy everyone would be doing it the right way. But the truth is that it is a long journey, and we are on the same bus of discovery with you all. 

Dr. Shawn Allen, one of the gait guys.

Reference:

Gait Posture. 2012 May;36(1):113-9. doi: 10.1016/j.gaitpost.2012.01.017. Epub 2012 Mar 3.How robust is human gait to muscle weakness?van der Krogt MM¹, Delp SL, Schwartz MH.

The effect of lower extremity fatigue on shock attenuation during single-leg landing.

Thank goodness the body can compensate. Here is a perfect example of this discussed in this study.
“ … it has been shown that a fatigued muscle decreases the body’s ability to attenuate shock from running. The purpose of the study was to determine the effect of lower extremity fatigue on shock attenuation and joint mechanics during a single-leg drop landing.”
This study suggests that as one part fatigued, the joint and muscle strategies elsewhere in the limb made up for it.
“Hip and knee flexion increased and ankle plantarflexion decreased at touchdown with fatigue. Hip joint work increased and ankle work decreased.” The results suggested that the lower extremity is able to adapt to fatigue though altering kinematics at impact and redistributing work to larger proximal muscles.

The effect of lower extremity fatigue on shock attenuation during single-leg landing. Clin Biomech (Bristol, Avon). 2006 Dec;21(10):1090-7. Epub 2006 Sep 1.
Coventry E1, O'Connor KM, Hart BA, Earl JE, Ebersole KT.
http://www.ncbi.nlm.nih.gov/pubmed/16949185

Rewiring.

The peripheral and central nervous systems are functionally
integrated regarding the consequences of a nerve injury: a
peripheral nerve lesion always results in profound and long lasting
central modifications and reorganization. (Kaas, 1991)
Does there need to be a lesion though ? A functional lesion will force changes just like an ablative lesion. Altered gait that persists from a sprained ankle or a painful knee will force central modifications and reorganization. This is why resolution of pain and aberrant function is critical. If you rehab to 80% you leave 20% on the table and that gets rewired into the system as the new norm. Remember, the entire system is watching, learning, adapting and rewiring all the time. This is why you must have a team in place to resolve all, if possible, of your client’s deficits. If you leave 20% of a problem on the table, and add endurance and strength to the “80%resolved:20%remaining”, you reorganize the central nervous system with that as the assumed norm moving forward. From this point forward, this is the architecture that all new patterns and forms are built from.  This sets up for long term rewiring of all of the connected parts, from motor, sensory, visual, gait, proprioceptive, vestibular and the list goes on and on. If you have ever wondered how a client can have so many areas of pain and dysfunction you might want to go back into their history and ask them if there was a single injury or event that occurred after which all their new problems started to stack up. 

If you are a gait analysis junkie, remember this principle above. All of the things you see in a person’s gait are not unconnected in many cases.  Much of what you see is a compensation around their problems, not the actual problem. 

Remember this principle: the peripheral nervous system attempts to repair by regrowth, the central nervous system attempts to repair by re-routing and reorganizing.

Dr. Shawn Allen

Is the "normal foot" normal ?

IF one foot is not normal, the other one cannot be “normal” either.  This is a blog post about symmetry, sort of.

This article just sort of seemed silly to us.

Imagine having a stone in one shoe and walking around in that shoe. Obviously you are gonna alter weight bearing in that shoe to avoid the pain and pressure of the stone. That means that the normal gait cycle of that foot/leg will be distorted somehow, the timed events of the gait cycle will be distorted and even likely the duration of the stance phase, heck, even plantar pressures will be changed.  Thus, the apparently “normal” foot on the opposite side will have an altered loading response and challenge because it will be receiving anything but normal biomechanics from the “stoned” shoe/foot.  Adaptation and compensation will have to occur, and not just in the “normal” foot, the entire body. 

Take another example, a sprained ankle. The brain will abbreviate the painful stance phase and abrupty depart the foot and thus create premature loading on the healthy foot, likely into mid-midstance which is usually met by midfoot strike and catching the body load with the quad thanks to abrupt knee flexion rather than early midstance with glute control during the loading response.  

Thus, if one foot is abnormal, there is just no way the so-called “normal” foot will be unaffected.  As this study suggests, the normal foot will have altered pedobarographic measurements.  Maybe we are missing the point here, but we suppose the words “relatively normal” or an “expected normal” should have been used. Yes, we may be splitting hairs here and discussing a relatively moot point, but our purpose was to just describe that since the two limbs are attached to the same body, if one side is not normal, a compensation has to occur in the other limb.  There is no other option.  We talk more about this concept in podcast 75 which will launch next week.

Shawn and Ivo, the gait guys

The contralateral foot in children with unilateral clubfoot, is the unaffected side normal?

http://www.gaitposture.com/article/S0966-6362(14)00523-2/abstract

Highlights

• •Pedobarographic measurements of unilateral unaffected clubfoot are not same as normal controls.
• •The unaffected foot should not be referred to as normal, nor should it be used as a control.
• •Timings of initiation of stance differ significantly between normal and unaffected clubfeet.
• •Unaffected clubfoot accumulates differences from normal feet due to maturation of gait with age.

Abstract

“Significant differences were identified between the unaffected side and normal controls for the pressure distribution, order of initial contact and foot contact time. These differences evolved and changed with age. The pedobarographic measurements of patients with clubfoot are not normal for the unaffected foot. As such the unaffected foot should not be referred to as normal, nor should it be used as a control.”

What is Visual Parallax and how does it affect gait analysis? : Is your video gait analysis really telling you what you think it is telling you ?

We recently were asked by a student at a physical therapy school to help with a teaching case. They asked us to look at a gait video to assist in outlining some things in the case.  Here was our response.

“Hello Jane Doe

We are happy to look at the video for you so you and others can learn.

Just please know, as we say all the time here on the Gait Guys, that without an examination that what we are all seeing is not the problem rather the persons compensatory strategy around the dysfunctional parts.

Plus, video negates binocular parallax viewing so things that would stand out in in a exam where we are physically present will be masked quite a bit in/on video or on a computer screen. We try to minimize these visual losses by getting multiplanar gait video views (sagittal from front and back and coronal from left and right sides) but even these will not fill the visual gap from transferring data from 3D to 2D and then trying to interpret a 3D answer from the 2D.  But it is the best one can do with our technology today unless you use a body suit sensor system, and then you still have the limitations of "what you see is not the problem, its their compensation” so one still needs the physical exam to put the puzzle together.

Here…….. read this if you are wondering what we mean.

*This blog article (link below) which we wrote 18 month ago is the heart of what we wanted you to read today. Visual parallax and binocular vision both need to be understood so that you can better understand why what you see on your gait analysis video might not be what  you think you are seeing. Seeing is one thing, knowing what you are seeing is another, knowing the limitations and the “why” of what you are seeing is yet another.

http://thegaitguys.tumblr.com/post/16760849274/what-is-visual-parallax-and-how-does-it-affect

So, we can tell you what we see………but without an exam we cannot tell you with great accuracy why you are seeing what we see.

that make sense ?“

best
shawn and ivo

Are you a Gait Troglodyte ? Are you sure ?

Are you a Gait Troglodyte ? Are you sure ? You might want to read on.

Most of us are all still in a cave and unacquainted with some of the affairs of the world. Some of us may find ourselves behind the times when it comes to GMO foods, social media, computers and the internet, smart phones while others may be behind on world issues and politics. Heck, some of us have never even seen “Ancient Aliens” on the History Channel !  It is hard to keep up with everything in this fast paced changing world. Something has to give for each of us and so we pick our poison and decide what it is that we are going to have to remain behind on when it comes to the learning curves of the world. And this is alright, but you have to first admit your “back of the pack” and “still living in a cave” type status on the issues and take some ribbing when acknowledging your limitations.  Failing to admit these inevitable shortcomings while pretending that you are still running with the pack can be a real problem. Not only are you faking yourself out but you may be deceiving those that you attempt to help.

Understanding gait, truly understanding it, is a monumental undertaking. This is why there are just no vast resources on it unlike other things in healthcare. Try going to PubMed and type in “arm swing”, you will see 318 articles. Try “pronation”, 2900 articles.  Now try “heart”, 1 million+ articles.  You get the point. Research is behind on gait, and thus our understanding of it is also poorly reflected in functional medicine and  human bodywork.  We are collectively gait troglodytes, living in stereotypical caveman times when it comes to gait.  Sure there are some good books like Perry’s text, or Michaud’s landmark work but there is a void on gait work and research. Human locomotion via gait (walking and running) is a small and poorly understood component by many. It is much the reason why we started The Gait Guys and began writing daily for over 600 days on gait issues. Little did we know that the door we had opened would continue to swing so wide and encompass so many other aspects that feed into human gait.

One of the aspects that worries us the most these days is the growing volume of “functional” work that is going on in the world of therapy and training.  There is a very important and critical place for this work and we fully admit that everyone needs to be on board with all of the great work that the leaders are teaching. What worries us is the apparent lack of integration of this work into gait assessment, gait therapy, and flawed gait neuro-biomechanics. Once again gait is not getting the pulpit it deserves. Yes, flaws in the functional screens and assessments need to be brought to light and remedied because they can impact bipedal locomotion but, the pendulum swings both ways. Gait can often be a cause of these functional problems that show up on the screens and assessments. If one fixes the functional pattern problems and the gait pattern is not restored then either the dysfunction will return or a new undesirable pattern will be generated. There needs to be more gait understanding and assessment from us all. Gait needs retraining as well, it is as much of a functional pattern as any other, if not more.  Gait deserves a pulpit as well.  Human assessment is clearly a two way street and it is not always clear who is the chicken and who is the egg. The problem may be that when gait does have its pulpit to speak from, who is the speaker ? A gait troglodyte or an expert ?

There will be folks who say we are over thinking this issue. There will be some who are offended. There will be some who cheer. There are some that will say “it will all come out in the wash” once the functional patterns are corrected elsewhere. They are wrong, it just is not that simple. Next to breathing, gait may be the second most compromised and corrupted functional pattern that humans express thousands of times daily. So, it is time to get busy.  It is time to peel off your Gait Troglodyte cloak and step into a 3 piece suit when it comes to understanding and interpreting gait.  If you are working in the world of human movement, locomotion, training, rehab and human biomechanics this is your next challenge.  Lets face it, we can either continue to walk around with our 10 year old flip phone understanding of gait or we can step up to a smart phone understanding of gait.  It is up to you, but know where you are and know your limitations. So be honest with yourself and your next client the next time you assess their gait. Be sure to ask yourself after seeing something that just doesn’t seem right in their gait, is what you see really what you are seeing ? Is that really what is wrong ? Or is it a compensation ? Do you know enough to see things for what they really are ?

Shawn and Ivo, The Gait Guys. 

We may not be Gait Troglodytes……. but some accuse us of living in a cave none the less.  However, if you have seen our cave, you will know it looks much like Bruce Wayne’s Batcave.  It isn’t your everyday cave.