When the going gets rough, we have a tendency to look down...

While working with a patient with runners dystonia the other day, I had one of those epiphanies. I thought I would share it with you here. Here is some food for thought. 

We remember that we have 3 systems that keep us upright in the gravitational plane: The visual system, the vestibular system and the proprioceptive system. As we age, we seem to become more dependent on the visual system, but that is a story we have told before here, and could certainly been expanded on in another post or three... 

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

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, all 4 of them! superior, inferior, medial and lateral); which then feed back up to the brain (medial, inferior and superior nuclear pathway) as well as down the spinal cord (the lateral pathway) to predominantly fire 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. Most actions in the nervous system are a system of checks and balances, or positives and negatives, and the one the one that predominates, is the one that wins : )

Look at the picture above. Notice the lateral semicicular canals are 30 degrees to the horizontal? If you are standing up and extending your head , that lateral canal becomes vertical and the fluid inside (emdolymph) cannot flow, making it much less useful to the nervous system. Thats why it is hard to stand with your head extended and eyes closed and maintain balance (go ahead and try it, feeling is believing). Conversely, when we flex our head forward(like looking down to see what our footing looks like), we move this lateral canal onto a more physiologically advantageous position, enhancingour balance.  If you are on uneven ground, have an injury or are having issues with proprioception (like many folks do), this actually helps the vestibular system (as well as the proprioceptive and visual systems) to work more efficiently. 

OK, have that? Now one more concept..

So if we look down, we put a slow stretch into our neck extensor muscles, which just happen to have some great postural receptors in them, called muscle spindles, along with mechanoreceptors in the capsules of the joints. So, facilitating (ie. exciting) these receptors, fires more information into our cerebellum, the queen of balance in the nervous system. What do you think happens? Even better balance and coordination! The 2 systems work together, summate to improve movement and balance!

Wow. All this from head position…The key here is to realize what and why you are doing what you are doing....

Want to be faster?

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If you want to be faster, you had better incorporate some proprioceptive training into your plan. It is the 1st part of our mantra: Skill, Endurance, and Strength (in that order). Proprioceptive training appears to be more important that strength or endurance training from an injury rehabilitation perspective injury rehabilitation perspective as well part of an injury prevention program

 What is proprioception? It is body position awareness; ie: knowing what your limbs are doing without having to look at them.

Take this simple test:

• Stand in a doorway with your shoes off. Keep your arms up at your sides so that you can brace yourself in case you start to fall. Lift your toes slightly so that only your foot tripod remains on the ground (ie the base of the big toe, the base of the little toe and the center of the heel.). Are you able to balance without difficulty? Good, all 3 systems (vision, vestibular and proprioceptive) are go.

• Now close your eyes, taking away vision from the 3 systems that keep us upright in the gravitational plane. Are you able to balance for 30 seconds? If so, your vestibular and proprioceptive systems are intact.

• Now open your eyes and look up at the ceiling. Provided you can balance without falling, now close your eyes. Extending your neck 60 degrees just took out the lateral semicircular canals of the vestibular system (see here for more info). Are you still able to balance for 30 seconds? If so, congrats; your proprioceptive system (the receptors in the joints, ligaments and muscles) is working great. If not, looks like you have some work to do. You can begin with exercises we use every day by clicking here.

Proprioception should be the 1st part of any training and/or rehabilitation program. If you don’t have a good framework to hang the rest of your training on, then you are asking for trouble. 

Timothy E. Hewett, PhD, , Kevin R. Ford, MS, Gregory D. Myer, MS, CSCS Anterior Cruciate Ligament Injuries in Female Athletes: Part 2, A Meta-analysis of Neuromuscular Interventions Aimed at Injury Prevention The American Journal of Sports Medicine Vol 34, Issue 3, pp. 490 - 498   link to free full text: http://journals.sagepub.com/doi/abs/10.1177/0363546505282619

Lephart SM1, Pincivero DM, Giraldo JL, Fu FH. The role of proprioception in the management and rehabilitation of athletic injuries. Am J Sports Med. 1997 Jan-Feb;25(1):130-7.

Party over the Weekend?

So, the more you drink, the more you impair the CNS. The more you impair the CNS, the more dependent you become on peripheral mechanisms. A good reason to keep your vestibular system (alcohol changes the specific gravity of the endolymph), your visual system (long term use affects the option nerve directly and can cause involuntary saccades) and proprioceptive systems including the cutaneous mechanoreceptors (because you are relying on them more) intact. Watch what and how much you drink...

"Standing postural stability relies on input from visual, vestibular, proprioceptive and mechanoreceptive sensors. When the information from any of these sensors is unavailable or disrupted, the central nervous system maintains postural stability by relying more on the contribution from the reliable sensors, termed sensory re-weighting. Alcohol intoxication is known to affect the integrity of the vestibular and visual systems. The aim was to assess how mechanoreceptive sensory information contributed to postural stability at 0.00% (i.e. sober), 0.06% and 0.10% blood alcohol concentration (BAC) in 25 healthy subjects (mean age 25.1 years). The subjects were assessed with eyes closed and eyes open under quiet standing and while standing was perturbed by repeated, random-length, vibratory stimulation of the calf muscles. Plantar cutaneous mechanoreceptive sensation was assessed for both receptor types: slowly adapting (tactile sensitivity) and rapidly adapting (vibration perception). The correlation between recorded torque variance and the sensation from both mechanoreceptor types was calculated. The recorded stability during alcohol intoxication was significantly influenced by both the tactile sensation and vibration perception of the subjects. Moreover, the study revealed a fluctuating association between the subjects' vibration perception and torque variance during balance perturbations, which was significantly influenced by the level of alcohol intoxication, vision and adaptation. Hence, one's ability to handle balance perturbations under the influence of alcohol is strongly dependent on accurate mechanoreceptive sensation and efficient sensory re-weighting. 

Modig F, Patel M, Magnusson M, Fransson PA.Study II: mechanoreceptive sensation is of increased importance for human postural control under alcohol intoxication. Gait Posture. 2012 Mar;35(3):419-27. doi: 10.1016/j.gaitpost.2011.11.001. Epub 2011 Dec 27.
weighting.

Turning: Connecting the kinetic chain

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

Rock Your Rehab Process with these simple Proprioceptive Exercises

In this capsule, excerpted from a recent Dry Needling Seminar, Dr Ivo talks about one of his proprioceptive sequences and the neurological reasoning behind it

Today we give away some of the farm with a great proprioceptive exercise sequence that we use ALL THE TIME.

Skill (proprioception), Endurance, Strength. In that order.

Try incorporating this simple and effective sequence into your rehab program and watch your results get even better!

Comparative effects of proprioceptive and isometric exercises on pain and difficulty in patients with knee osteoarthritis: A randomised control study. Ojoawo AO, Matthew O, Mariam HA.Technol Health Care. 2016 Jul 8. [Epub ahead of print]

Efficacity of exercise training on multiple sclerosis patients with cognitive impairments. Chenet A, Gosseaume A, Wiertlewski S, Perrouin-Verbe B. Ann Phys Rehabil Med. 2016 Sep;59S:e42. doi: 10.1016/j.rehab.2016.07.097.

Exercise strategies to protect against the impact of short-term reduced physical activity on muscle function and markers of health in older men: study protocol for a randomised controlled trial. Perkin OJ, Travers RL, Gonzalez JT, Turner JE, Gillison F, Wilson C, McGuigan PM, Thompson D, Stokes KA. Trials. 2016 Aug 2;17:381. doi: 10.1186/s13063-016-1440-z.

Leg and trunk muscle coordination and postural sway during increasingly difficult standing balancetasks in young and older adults. Donath L, Kurz E, Roth R, Zahner L, Faude O.Maturitas. 2016 Sep;91:60-8. doi: 10.1016/j.maturitas.2016.05.010. Epub 2016 May 27.

Hip proprioceptive feedback influences the control of mediolateral stability during human walking. Roden-Reynolds DC, Walker MH, Wasserman CR, Dean JC. J Neurophysiol. 2015 Oct;114(4):2220-9. doi: 10.1152/jn.00551.2015. Epub 2015 Aug 19.

Proprioceptive Training and Injury Prevention in a Professional Men's Basketball Team: A Six-Year Prospective Study. Riva D, Bianchi R, Rocca F, Mamo C.J Strength Cond Res. 2016 Feb;30(2):461-75. doi: 10.1519/JSC.0000000000001097.

Proprioceptive feedback contributes to the adaptation toward an economical gait pattern. Hubbuch JE, Bennett BW, Dean JC. J Biomech. 2015 Aug 20;48(11):2925-31. doi: 10.1016/j.jbiomech.2015.04.024. Epub 2015 Apr 23.

Our neurology mentor, Dr. Carrick discusses the vestibular system and what can go wrong with it and what happens to our locomotion system when it doesn’t function properly.  

Gait: sometimes it is about the ear (sort of).

We have talked on several occasions about the aging population and the high morbidity and mortality rates with falls in this population. We have discussed the eyes, dual tasking, changes in environment and many other factors that play seamlessly into normal gait, things we all take for granted. But the aging population has yet another challenge, declining function of the vestibular apparatus. We often hear about balance, and we tend to treat it without truly thinking that this is a integration of the eyes, ears and proprioceptive systems together. If you have clients with multiple falls for unknown reasons, it is time to send them for a check up of the mechanical components of the vestibular system (and visual check up as well) you should be able to do the functional vestibular assessments in your office for the most part.

Recent studies are showing significant declines in semicircular canal function in each of the canal planes as well as otolith function within the aging population. “These findings suggest that age-related slowing of gait speed is in part mediated by the decreased magnitude of saccular response associated with age. ” -Ferrucci study

While the Agrawal study suggested “an overall decline in semicircular canal as well as otolith function associated with aging, although the magnitude of impairment was greater for the semicircular canals than the otoliths in this elderly population. A better understanding of the specific vestibular deficits that occur with aging can inform the development of rational screening, vestibular rehabilitation, and fall risk reduction strategies in older individuals.”

Dr. Shawn Allen, the gait guys

References:

Otol Neurotol. 2015 Jan 7. [Epub ahead of print]
Association Between Saccular Function and Gait Speed: Data From the Baltimore Longitudinal Study of Aging. Layman AJ1, Li C, Simonsick E, Ferrucci L, Carey JP, Agrawal Y.

Otol Neurotol. 2012 Jul;33(5):832-9. doi: 10.1097/MAO.0b013e3182545061.
Decline in semicircular canal and otolith function with age.
Agrawal Y1, Zuniga MG, Davalos-Bichara M, Schubert MC, Walston JD, Hughes J, Carey JP.

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.

Take this simple test. 

Want to be faster? Better incorporate some proprioceptive training into your plan. It is the 1^st part of our mantra: Skill, Endurance, and Strength (in that order). Proprioceptive training appears to be more important that strength or endurance training from an injury rehabilitation perspective as well part of an injury prevention program

 What is proprioception? It is body position awareness; ie: knowing what your limbs are doing without having to look at them.

Take this simple test:

• Stand in a doorway with your shoes off. Keep your arms up at your sides so that you can brace yourself in case you start to fall. Lift your toes slightly so that only your foot tripod remains on the ground (ie the base of the big toe, the base of the little toe and the center of the heel.). Are you able to balance without difficulty? Good, all 3 systems (vision, vestibular and proprioceptive) are go.

• Now close your eyes, taking away vision from the 3 systems that keep us upright in the gravitational plane. Are you able to balance for 30 seconds? If so, your vestibular and proprioceptive systems are intact.

• Now open your eyes and look up at the ceiling. Provided you can balance without falling, now close your eyes. Extending your neck 60 degrees just took out the lateral semicircular canals of the vestibular system (see here for more info). Are you still able to balance for 30 seconds? If so, congrats; your proprioceptive system (the receptors in the joints, ligaments and muscles) is working great. If not, looks like you have some work to do. You can begin with exercises we use every day by clicking here.

Proprioception should be the 1st part of any training and/or rehabilitation program. If you don’t have a good framework to hang the rest of your training on, then you are asking for trouble. 

The Gait Guys. Your proprioceptive mentors. We want you to succeed!

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.

OK. HEAVY CONCEPT APPROACHING

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….