Podcast 78: Step Width Gait, Training Asymmetries & more

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Today’s Show notes:

24-year-old woman missing entire cerebellum exemplifies the amazing power of brain plasticity

Brain scans reveal ‘gray matter’ differences in media multitaskers

Who are we: Ivo talk a bit about yourself and your educational history and what is your website ?
Shawn…..do the same
and……lets keep each interesting but to just a few minutes
Effect of step width manipulation on tibial stress during running
Does Limited Internal Femoral Rotation Increase Peak Anterior Cruciate Ligament Strain During a Simulated Pivot Landing?
Quadriceps Muscle Function After Exercise in Men and Women With a History of Anterior Cruciate Ligament Reconstruction

Rewind double feature! Part 2

(for part 1, click here)

In conjunction with the latest PODcast talking about efferent copy, we thought it appropriate to talk about the cerebellum here. In this capsule we talk about the efferent pathways

Enjoy! and have a nice weekend (not that we are telling you what to do…)

Ivo and Shawn

Rewind double feature! Part 1

A first ever her on TGG. With the latest PODcast talking about efferent copy, we thought it appropriate to talk about the cerebellum here.

Enjoy! and have a nice weekend (not that we are telling you what to do…)

Ivo and Shawn

Things may not always be how they appear.

What can you notice about all these kids that you may not have noticed before?

Look north for a moment. What do you notice about all the kids with a head tilt? We are talking about girl in pink on viewers left, gentleman in red 2nd from left, blue shirt all the way on viewers right. Notice how the posture of the 2 on the left are very similar and the one on the right is the mirror image?

What can be said about the rest of their body posture? Can you see how the body is trying to move so that the eyes can be parallel with the horizon? This is part of a vestibulo cerebellar reflex. The system is designed to try and keep the eyes parallel with the horizon. The semicircular canals (see above), located medial to your ears, sense linear and angular acceleration. These structures feed head position information to the cerebellum which then forwards it to the vestibular nucleii, which sends messages down the vestibulo spinal tract and up the medial longitudinal fasiculus to adjust the body position and eye position accordingly. 

Can you see how when we add another parameter to the postural position (in this case, running; yes, it may be staged, but the reflex persists despite that. Neurology does not lie), that there can be a compensation that you may not have expected?

What if one of these 3 (or all three) kids had neck pain. Can you see how it may not be coming from the neck. What do you think happens with cortical (re)mapping over many years of a compensation like this? Hmmm. Makes you think, eh?

Ivo and Shawn. The Gait Guys. Taking you a little further down the rabbit hole, each and every post.

Do you do manual muscle testing?

Following up on yesterdays post…
We all like to evaluate our patients; hopefully on the table as well as observation while weight bearing. Here is some food for thought.

When your patient or client is lying on the table, do you pay attention to where there head is in space (ie the position of their head)? Why should you care?

Remember our post on facilitation (if not, click here)? That has something to do with it.

Here is the short story. Make sure the head is neutral and midline (lined up between the shoulders), there is good preservation of the cervical curve , with a small pillow supporting the neck, but not altering it’s angle.

The long story involves the vestibular system. It is a part of the nervous system that lives between your ears (literally) and monitors position and velocity of movement of the head. There are three hula hoop type structures called “semicircular canals” (see picture above) that monitor rotational and tilt position and angular acceleration, as well as two other structures, the utricle and saccule, which monitor tilt and linear acceleration. I think you can see where this is going….

The vestibular apparatus (the canals and the utricle and saccule) feed into a part of the brain called the floccular nodular lobe of the cerebellum, which as we are sure you can imagine, have something to do with balance and coordination. This area of the cerebellum feeds back to the vestibular system (actually the vestibular nucleii); which then feed back up to the brain as well as (you guessed it) down the spinal cord and to predominantly the extensor muscles.

So, what do you think happens if we facilitate (or defaciltate) a neuronal pool? We alter outcomes and don’t see a clear picture.

Look at the picture above. Notice the lateral semicicular canals are 30 degrees to the horizontal? If you are lying flat, they are now at 60 degrees. If the head is resting on a pillow and flexed forward 30 degrees, the canals are vertical and rendered inoperable. This could be good (or bad) depending on what muscle groups you are testing.


So if we defacilitate the extensors, what happens to the flexors? Remember reciprocal inhibition (If not click here)? According to the law of reciprocal innervation, the flexors will be MORE FACILITATED. If the extensors are faciltated, they will appear MORE ACTIVE and the flexors LESS ACTIVE.

Wow. All this from head position…The key herer is to know what you are doing, This gait stuff can get pretty complex; but don’t worry. We aren’t going anywhere and are here to teach you.

The Gait Guys . Gait Geeks are the new cool….

Why do we have difficulty with our gait when we drink too much alcohol ? It is not unlike the disturbed sense of balance we experience when we have an inner ear problem such as an infection.

Alcohol affects one’s balance by changing the viscosity of the endolymph within the otolithic membrane, the fluid inside the semicircular canals inside the ear. The endolymph surrounds the cupula which contains hair cells within the semicircular canals. When the head is tilted, the endolymph flows and moves the cupula. The hair cells then bend and send signals to the brain indicating the direction in which the head is tilted. By changing the viscosity of the endolymph to become less dense when alcohol enters the system, the hair cells can move more easily within the ear, which sends the signal to the brain and results in exaggerated and overcompensated movements of body. This can also result in vertigo, or “the spins.”  Many of us have experienced this event in one shape or another and we know what it feels like.  The unsteadiness of our gait is disturbing and uncorrectable until the problem is solved or the alcohol’s effect wear off.  In chronic alcoholism however, the problem is different and more lasting.

Disturbed gait and balance are among the most consistent sequelae of chronic alcoholism. Research studies have shown evidence that partial recovery of gait and balance functions in alcoholics may be achieved with abstinence. This study ( http://www.ncbi.nlm.nih.gov/pubmed/21919921)  showed that alcoholics’ gait and balance can continue to recover with long abstinence from alcohol, but that deficits persist, especially in eyes-closed standing balance.


Chronic alcohol abuse consistently damages the cerebellum. The cerebellum has multiple functions, including control of balance and coordination and even motor pattern generation. Alcohol also damages subcortical white matter, the myelinated fiber tracts that connect different parts of the cortex, and other central nervous systems. Long-term alcohol dependence also results in impaired dopamine transmission in the striatum, an important area for motor control.

The next time you are the designated driver, spend some time appreciating the subtle nuances and changes in people’s gait. Not only is it amusing, but fascinating as well.

Studies quoted in this blog post.

(Smith and Fein, 2011, Alcohol Clin Exp Res 35:2184–2192)


Gait and Balance Deficits in Chronic Alcoholics: No Improvement from 10 Weeks Through 1 Year Abstinence

Don’t let the title scare you. While watching this excerpt from an acupuncture lecture, think about the implications for gait.

In this installment of Neuromechanics weekly, we discuss how everything we do, smell, see or hear influences muscle tone through the cerebellum. The take home message is environmental cues as well as therapeutic ones will influence muscle tone via the muscle spindles..

You just can’t get away from neurology. It is EVERYWHERE!

Just when you thought it was safe to watch a Neuromechanics Weekly episode, Dr Ivo throws a curveball. Check out the interesting clinical asides about myelopathy (pressure on the spinal cord causing ataxic gait) and the importance of which modality to check 1st, when doing an exam.

Keep these things in mind the next time you are evaluating someone’s gait.

Today on Neuromechanics Weekly, we explain how the autonomic nervous system is linked to brain activity, particularly the cerebellum, which we all know is intimately linked to gait, walking and running. Now you will understand why you get dizzy when you have pain or why your heart beats faster or harder (they are different sides of the brain). Join Dr Waerlop in this fascinating lecture.

The Gait Guys…Providing explanations and making the complex easier to understand