#motor patterns

The early locomotor experience , a free play spontaneous study Once again, we learn from our mistakes, or we should at least. This natural locomotion study suggests that better walkers spontaneously walk more and fall less.

"Twelve- to 19-month-olds averaged 2,368 steps and 17 falls per hour. Novice walkers traveled farther faster than expert crawlers, but had comparable fall rates, which suggests that increased efficiency without increased cost motivates expert crawlers to transition to walking. After walking onset, natural locomotion improved dramatically: Infants took more steps, traveled farther distances, and fell less. Walking was distributed in short bouts with variable paths--frequently too short or irregular to qualify as periodic gait. Nonetheless, measures of periodic gait and of natural locomotion were correlated, which indicates that better walkers spontaneously walk more and fall less. Immense amounts of time-distributed, variable practice constitute the natural practice regimen for learning to walk."

We have discussed on recent podcasts about the concept of neuro-adaptation. Neuro-adaptation is the initial strength gains we see in the first few weeks of corrective exercise homework, often it is more so better "coordination" of the motor patterns taught, and less so brute strength. But, it applies to strength training as well.

This strength increase is usually attributed to changes in the neural drive to muscle as a result of adaptations at the cortical or spinal level. This study investigated the change in the discharge characteristics of large populations of longitudinally tracked motor units in tibialis anterior before and after 4 weeks of strength training the ankle‐dorsiflexor muscles with isometric contractions. “

"We show for the first time that the discharge characteristics of motor units in the tibialis anterior muscle tracked across the intervention are changed by 4 weeks of strength training with isometric voluntary contractions.” ”The specific adaptations included significant increases in motor unit discharge rate, decreases in the recruitment‐threshold force of motor units and a similar input–output gain of the motor neurons. The findings suggest that the adaptations in motor unit function may be attributable to changes in synaptic input to the motor neuron pool or to adaptations in intrinsic motor neuron properties." -Alessandro Del Vecchio et al

“These results demonstrate for the first time that the increase in muscle force after 4 weeks of strength training is the result of an increase in motor neuron output from the spinal cord to the muscle. “

The increase in muscle force after 4 weeks of strength training is mediated by adaptations in motor unit recruitment and rate coding Alessandro Del Vecchio et al Journal of physiology 06 February 2019

Nose picking and running form

Last week we did a presentation on some very classic, yet challenging, gait video case presentations. This slide was a big piece of our presentation.  We discussed that there are volitional and non-volitional movements that accompany the adequate and appropriate postural system control. If you want to hurt your brain, read this paper.  But in a nutshell what this paper says is that we have a constant switching between steady state cortical neuron discharge and and non-steady state discharge. For example, when we are on a flat road, no obstacles ahead of us, nothing but boring open road, the system sort of runs on an automated program, making limb movements calculated off of a normal unchallenged baseline. But, if there are roots, rocks, curbs, bikes to dodge, puddles to hurdle etc, the volitional and postural systems must change their operation, and alter limb movements based off of those postural systems as we pay attention, and negotiate the obstacles. There is this delicate symphony occurring between automated posture, calculated posture, rhythmic limb movements. In other words, there are volitional, reactionary and anticipatory plans and adjustments occurring in the background at all times. But, make no mistake, bad, faulty, inefficient motor patterns can become automated if injuries are left, if they are left partially rehabed, if we teach our clients faulty patterns by overloading them and forcing adaptive patterns to inappropriate load or fatigue. These modifications occur deep in the CNS, much in the premotor cortices, and take into account body schema (their correct or distorted perception of where they are, or their limbs are, in space). Build strength or endurance on an altered schema, one that might be present from an old injury, and one will build strength and endurance where one does not want them to go. Properly training clients, offering corrective exercise and the like is far deeper that just asking your client to load and get stronger, unless you wish to assume that their limitations and compensations are unimportant. This takes us right back to the asymmetry debate, which we know so many love to dive into. Asymmetry is the norm of course, just don't be the person creating more of it for your client.

Running, gait, human sociomotor interactions and the power of behavioral plasticity.

A. Podcast links:

http://traffic.libsyn.com/thegaitguys/pod_108f.mp3

http://thegaitguys.libsyn.com/podcast-108-motor-signatures-motor-learning-calf-power

B. iTunes link: https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138

C. Gait Guys online /download store (National Shoe Fit Certification & more !) http://store.payloadz.com/results/results.aspx?m=80204

D. other web based Gait Guys lectures: Monthly lectures at : www.onlinece.com type in Dr. Waerlop or Dr. Allen, ”Biomechanics”

-Our Book: Pedographs and Gait Analysis and Clinical Case Studies Electronic copies available here:

-Amazon/Kindle: http://www.amazon.com/Pedographs-Gait-Analysis-Clinical-Studies-ebook/dp/B00AC18M3E

-Barnes and Noble / Nook Reader: http://www.barnesandnoble.com/w/pedographs-and-gait-analysis-ivo-waerlop-and-shawn-allen/1112754833?ean=9781466953895

https://itunes.apple.com/us/book/pedographs-and-gait-analysis/id554516085?mt=11

-Hardcopy available from our publisher: http://bookstore.trafford.com/Products/SKU-000155825/Pedographs-and-Gait-Analysis.aspx

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Show Notes:

The way you move gives clues. http://neurosciencenews.com/movement-personality-traits-3907/

http://rsif.royalsocietypublishing.org/content/13/116/20151093

Biomechanics of Propulsion http://lermagazine.com/cover_story/biomechanics-of-propulsion-implications-for-afos

Does variability in muscle activity reflect a preferred way of moving or just reflect what they've always done? In this study it was found that there isn't always this tight relationship between activity in the muscles and the movement we're seeing. "Clearly, locomotion is not as simple as we thought it was," Foster said. "This decoupling -- big changes in movement without corresponding changes in muscle activity -- suggests there are other important factors going on and we need to better understand them if we want to reproduce these movements in prosthetics or robotics." Hmmmm. thoughts. this makes everything more interesting doesn't it ?!

"Neural circuits linking activity in anatomically segregated populations of neurons in subcortical structures and the neocortex throughout the human brain regulate complex behaviors such as walking, talking, language comprehension, and other cognitive functions associated with frontal lobes.” 1

We also found this interesting quote from Science Daily on this topic of complex sensory motor behaviors and on the varying information on central pattern generators.

ScienceDaily (June 3, 2012) — “A new finding that motor cortex is a dynamic pattern generator upends existing theory with broad implications for neuroscience.”

“Maybe it is actually easier to understand than we thought. A new paper presents some compelling evidence that the motor cortex, rather than being command central, is more like a part of the machine, sending rhythmic signals down the spinal cord to orchestrate movement.”

"The electrical signal that drives a given movement is therefore an amalgam — a summation — of the rhythms of all the motor neurons firing at a given moment." This is of course monitored (and modified) by one of our best friends, the cerebellum. 2

The cortex is where movement begins and where it ends; from areas 4, 4s and 6 in the precentral gyrus of the brain’s frontal lobe, down the spinal cord and out to the muscle through the peripheral nerve.   It is also where the information from the body’s receptors feed back,  to give updates on where the body parts are in space (proprioception) and how they are doing functionally (comparing information about length, tension, etc).  It is about sensory and motor function.  Motor function is based on sensory input.  Good motor function is based on good sensory information. It is a subtle, beautiful, intricate symphony.  And when one part goes wrong, the whole system can be thrown off.  

Here is an example we sometimes use in our lectures and with our patients to make this point clear.  Imagine an orchestra playing Beethoven’s beautiful Ode to Joy, a choral symphony for orchestra.  Now imagine one of the musicians begins to play off key. In time, the musicians sitting around that musician who are most locally influenced by that off tune musician, soon become irritated and have troubles playing “in tune”. In time, if not rectified, the whole orchestra could be corrupted and being to take that lead as well.  Hard to believe, but it makes the point that all it takes is one piece not playing well to change the outcome. Similar analogy, all it takes is one weak muscle or one painful joint and the outcome is skewed away from the optimal outcome and in time local dysfunction and compensation becomes an all encompassing compensation. The body’s function and operation, when proper, is an orchestra and orchestration with each piece doing a local job with a more global contribution to the bigger job. When all pieces come together appropriately it creates a symphony of flawless, effortless movement as seen in the video above.

Shawn and Ivo, the gait guys

refs:

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.