A symptomatic tendon affects more than the local area it finds itself, it "affects the neuromuscular control on the involved side but not the non-involved side. The muscle–tendon unit on the tendinotic side exhibits a lowered temporal efficiency, which leads to altered CNS control. The altered CNS control is then expressed as an adapted muscle activation pattern in the lower leg". - Yu-Jen Chang and Kornelia Kulig
. . . 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
Today we look at a simple CNS screen for your “central pattern generators” or “CPG’s”. If you do not pass, then the exercise becomes the rehab exercise. If you (or your client) does not have good coordination between the upper and lower extremity, then they will not be that efficient, physiologically or metabolically.
The “cross crawl” or “step test” looks at upper and lower extremity coordination, rather than muscular strength. If performed for a few minutes, it becomes a test that can look at endurance as well.
It is based on the “crossed extensor” response, we looked at last week. That is, when one lower limb flexes, the other extends; the contralateral upper limb also flexes and the ipsilateral upper limb extends. It mimics the way things should move when walking or running.
- Stand (or have your client stand) in a place where you will not run into anything.
- Begin marching in place.
- Observe for a few seconds. When you (or your client) are flexing the right thigh, the left arm should flex as well; then the left thigh and right arm. Are your (their) arms moving? Are they coordinated with the lower extremity?
- What happens after a few minutes? Is motion good at 1st and then breaks down?
- Now speed up. What happens? Is the movement smooth and coordinated? Choppy? Discoordinated?
- now slow back down and try it with your (their) eyes closed
If movement is smooth and coordinated, you (they) pass
If movement is choppy or discoordinated, there can be many causes, from simple (muscle not firing, injury) to complex (physical or physiological lesion in the CNS).
- If movement is not smooth and coordinated, try doing the exercise for a few minutes a day. You can even start sitting down, if you (they) cannot perform it standing. If it improves, great; you were able to help “reprogram” the system. If not, then you (they) should seek out a qualified individual for some assistance and to get to the root of the problem.
We go deep on how injuries get logged deep in the CNS, what to do and how to get around it all. Join us today !
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Imagining workouts can improve strength
Your injuries are not forgotten
Look at the photo, which way am I turning my head ? How hard am I turning ? Perhaps I am turning hard through my neck and thoracic spine to look over my shoulder. The point is, you can see it in my feet and if you know your biomechanics you should easily know which way I am turned.
It should be simple and clear that I am turning my neck and thoracic spine strongly to the left. The left rotation has forced me to find stability over the lateral left foot while driving the rotation with the right foot. Left foot had to supinate, right had to pronate. No rocket science here.
Earlier in the week I posted a brief discussion on the neck and proprioception and the upper and lower limb. I caught some questions on challenging the strength of the neurological linkages to the lower limb, so I promised a simple picture to solidify my point.
Where is what i wrote earlier this week.
"From the study: "Limb proprioception is an awareness by the central nervous system (CNS) of the location of a limb in three-dimensional space and is essential for movement and postural control. The CNS uses the position of the head and neck when interpreting the position of the upper limb, and altered input from neck muscles may affect the sensory inputs to the CNS and consequently may impair the awareness of upper limb joint position."
We say it is not just the upper limb however, the neck and head posture is used in interpreting the position of the lower limb as well. And similarly altered head/neck muscle input can impair awareness of the lower limb posture as well. Think about it, we are trying to stay upright in the gravitational plane while keeping the eyes and vestibular centers on the horizon. Gait is nothing more than a single leg balancing act repeated over and over. Faulty info on where our center of pressure is from a visual or vestibular aspect will alter where we put our foot in space. Just look at how many neurologic diseases end up with a wider based gait, because our proprioceptive centers no longer trust our base of support. It is all connected."
Exp Brain Res. 2015 May;233(5):1663-75. doi: 10.1007/s00221-015-4240-x. Epub 2015 Mar 13.
Neck muscle fatigue alters upper limb proprioception.
Zabihhosseinian M1, Holmes MW, Murphy B.
As in this study, and putting it together with my photo and discussion at the start here today, limb proprioception is an awareness by the CNS of the location of the limb and is essential for proper movement and postural control. If I had rotated to the left and had my CNS not known where the foot was in space and in relation to the rest of my body, I may have fallen over to the left. Instead, my CNS sensed the weight shift to the left from the neck and torso rotation, and moved my foot weight bearing into supination (affording a slightly greater lateral weight bearing on the foot) to accommodate the shift in my center of pressure and mass laterally. So, the CNS used the position of the head and neck, and the weight shift, in interpreting the appropriate positioning of the lower limbs. Sometimes moving the foot into supination to accommodate the lateral load is not enough, and we need to actually step laterally to maintain upright. Altered input from my neck muscles might affect the sensory inputs to the CNS and consequently may impair the awareness of my limb joint positioning in space. This happens often in vestibular challenged clients and in client of aging decline where the system is losing proprioception. If we do not know where a body part is in space, we don't know how to use it or how to load it (think about chronic ankle sprains).
As i said earlier this week, think about it, we are trying to stay upright in the gravitational plane while keeping the eyes and vestibular centers on the horizon. Gait is nothing more than a single leg balancing act repeated over and over. Faulty info on where our center of pressure is from a visual or vestibular aspect will alter where we put our foot in space. Just look at how many neurologic diseases end up with a wider based gait, because our proprioceptive centers no longer trust our base of support. It is all connected.
Think about how amazing this system is when it works right, we can run on a track leaning into the curve, we can ride a bike and lean into turns, we can run forward and yet turn to look behind us, all without falling over -- thanks to our CNS and joint proprioception.
Dr. Shawn Allen, the other gait guy
Plus: Changing an existing orthotic to make it work, Meniscal tear truths, Shoe Insole truths, Plantar Pressures
Other Gait Guys stuff
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Running helps mice slow cancer growth
The future of Wearables
mensicus surgery is dead ?
Why you should be training your CNS
The business of insoles
Altered plantar pressures
Trying to reteach your client’s CNS new sensory-motor patterns so they can move better ? We like to say that the first few weeks are like paying down a mortgage, you do not own them, you are cerebrally renting those changes and barely paying down the principle. It takes focused work and time to truly own the changes so that they translate into better movement.
“Depending on the complexity of the activity, [experiments have required] four and a half months, 144 days or even three months for a new brain map, equal in complexity to an old one, to be created in the motor cortex.” -Swart
New connections and pathways are fragile and only through repetition and practice and focused attention can those connections be established enough to become habitual or default behaviors.
Neuroscience for Leadership: Harnessing the Brain Gain Advantage (The Neuroscience of Business). Tara Swart