The Adductor Magnus; Not just for adduction anymore...

Yet another paper (1) to support the notion that the adductors (particularly the adductor magnus, in this paper), act as external rotators (especially eccentrically), not internal rotators as is commonly purported in many anatomy texts (2) . Remember that the lower extremity is internally rotating (as a whole) from initial contact to midstance and externally rotating from midstance to pre swing. SOMETHING needs to help attenuate some of that internal rotation (and pronation) that occurs during the 1st part of stance phase and assist in external rotation (and supination); now you can add the adductor magnus to the popliteus, deep six external rotators, anterior and posterior compartments of the lower leg to the hamstrings and quads.

"This study suggests that adductor magnus has at least two functionally unique regions. Differences were most evident during rotation. The different direction-specific actions may imply that each segment performs separate roles in hip stability and movement. These findings may have implications on injury prevention and rehabilitation for adductor-related groin injuries, hamstring strain injury and hip pathology."

1. Benn ML, Pizzari T, Rath L, Tucker K, Semciw AI1 . Adductor magnus: An emg investigation into proximal and distal portions and direction specific action. Clin Anat. 2018 Mar 9. doi: 10.1002/ca.23068. [Epub ahead of print]

2. Leighton RD. A functional model to describe the action of the adductor muscles at the hip in the transverse plane.Physiother Theory Pract. 2006 Nov;22(5):251-62.



 

Gait: How we stay upright in the gravitational plane.

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 upon the visual system to maintain stability of the head (which is largely under the purview of the vestibular system). Older folks seem to be less stable than younger ones....At least when it comes to head stability.

This study looked at the neuromechanical mechanisms of head stability in younger and older women during gait initiation, a time when we employ the visual system for things like balance and foot placement. The visual system in this case is king and trumps the other systems in that it will do whatever it need to to keep the eyes level with the horizon.

They used a stereophotogrammetric system to measure angular displacement and acceleration and surface emg (no, not the best) to look at activation latencies of neck (particularly the SCM), trunk and pelvic muscles. Older women had higher variability in angular displacement of the head (possibly age related breakdown of the vestibular system?), decreased ability to attenuate accelerations in the sagittal (forward) plane, and increased SCM activation latencies.

The bottom line?

Make sure the older women you are working with have:

- better functioning joints
- better functioning muscles (appropriate skill, endurance and strength)
- better proprioception

You could help these by:

- manipulating and mobilizing joints that have pathomechanics
- improving muscular function through endurance and strength based exercises of the neck as well as core
-improving muscular function through modalities you use
-give them more proprioceptive based exercises, especially ones which incorporate the head, like head repositioning exercises,
-encourage them to engage in proprioceptive heavy activities, like rock climbing (which also works the axial extensors), cross country skiing, bike riding, etc

Maslivec A, Bampouras T, Dewhurst S, Vannozzi G, Macaluso A, Laudani L. Mechanisms of head stability during gait initiation in young and older women: A neuro-mechanical analysis.
J Electromyogr Kinesiol. 2017 Nov 23;38:103-110. doi: 10.1016/j.jelekin.2017.11.010. [Epub ahead of print]

link to free full text: https://www.sciencedirect.com/science/article/pii/S1050641116302036?via%3Dihub

Gait and spinal cord reflexes

Gait and the spinal cord reflexes and inhibitory processes.

It is important that we all understand this, especially those that think they can retrain or correct people's gait and running form just by adding mere corrective suggestions from data and video.

Research by the lab of Martyn Goulding reveals that specific neurons called RORbeta (RORβ) interneurons inhibit transmission of potentially disruptive sensory information during walking in order to promote a fluid gait.

This new research shows us that so much more is going on in our spinal cord that we previously knew. The cord seems to know when to process information and when to ignore it so as to not be distracted. This is good, because the brain cannot process all of this information all the time, some of it has to be spinal cord reflexively dealt with. We have discussed presynaptic inhibitory interneuron work a few times on our The Gait Guys podcast over the years and this new research is confirming this process even further. In many respects, this new research is nothing new, but it seems to go deeper, which is very exciting.

"The work, appearing in the journal Neuron on December 7, 2017, reveals that specific neurons called RORbeta (RORβ) interneurons inhibit transmission of potentially disruptive sensory information during walking in order to promote a fluid gait. The research illustrates a high level of sophistication in spinal cord information processing.

"When we are moving, motor circuits in the spinal cord are constantly being barraged by information from sensory receptors in the skin and muscles, telling these circuits what our limbs are doing or what the ground underfoot feels like. This information is critical for actions like walking or standing still. Often these actions are at odds with each other, so a big question in neuroscience has been how our spinal cord “gates” or traffics different kinds of sensory information that might cause conflicting actions, to ensure that each movement is performed properly."

" . . . RORβ interneurons are gating–inhibiting–irrelevant sensory information that would interfere with the normal stepping pattern. When RORβ is present, each step is a smooth fluid motion, but when absent, the legs become excessively flexed (bent) and each step is awkward. In humans this would be akin to your knee continuing to stay bent for too long with each step."

http://neurosciencenews.com/rorbeta-spinal-cord-8147/

Proprioceptive Clues in Children’s Gait.

This goes along with Mondays post. We can learn a lot about gait from watching our children walk. An immature nervous system is very similar to one which is compensating meaning cheating around a more proper and desirable movement pattern; we often resort to a more primitive state when challenges beyond our ability are presented. This is very common when we lose some aspect of proprioception, particularly from some peripheral joint or muscle, which in turn, leads to a loss of cerebellar input (and thus cerebellar function). Remember, the cerebellum is a temporal pattern generating center so a loss of cerebellar sensory input leads to poor pattern generation output. Watch this clip several times and then try and note each of the following:

• wide based gait; this is because proprioception is still developing (joint and muscle mechanoreceptors and of course, the spino cerebellar pathways and motor cortex)
• increased progression angle of the feet: this again is to try and retain stability. External rotation allows them to access a greater portion of the glute max and the frontal plane (engaging an additional plane is always more stable).
• shortened step length; this keeps the center of gravity close to the body and makes corrections for errors that much easier (remember our myelopathy case from last week ? LINK. This immature DEVELOPING system is very much like a mature system that is REGRESSING. This is a paramount learning point !)
• decreased speed of movement; this allows more time to process proprioceptive clues, creating accuracy of motion

Remember that Crosby, Still, Nash and young song “Teach Your Children”? It is more like, “teach your parents”…

Proprioceptive clues are an important aspect of gait analysis, in both the young and old, especially since we tend to revert back to an earlier phase of development when we have an injury or dysfunction.

What did you notice? The Devil is in the details...

 Cavus foot? Loss of the transverse arch? Prominence of extensor tendons?

The question is: Why?

It’s about reciprocal inhibition. The concept, though observed in the 19th century, was not fully understood and accepted until it earned a Nobel prize for its creditor, Sir Charles Sherrington, in 1932. Simply put, when a muscle contracts, its antagonist is neurologically inhibited, So when your bicep contracts, your tricep is inhibited. This holds true whether you actively contract the muscle or if the muscle is irritated (causing contraction).

So how does this apply to this foot?

We see prominence of the extensor tendons (particularly the extensor digitorum brevis EDB; the longus would have caused extension at the distal interphalangeal joint). The belly of the muscle is visible, telling us that it is active. It is neurologically linked to the flexor digitorum brevis (FDB). This muscle, in turn, has slips which attach it to the abductor hallucis brevis (AHB) medially and the abductor digiti minimi (ADM) laterally. These muscles together form 2 triangles (to be discussed in another post) on the bottom of the foot, which lend to the stability of the foot and the arches, especially the transverse.

When the EDB fires, it inhibits the FDB, (which, in addition to flexing the MTP’s, assists in maintaining the arch). The EDB has an effect which drops the distal heads of the metatarsals as well (Hmm, think about all the people with met head pain) Now, look at the course of the tendons of the EDB. In a cavus foot, there is also a mild abductory moment, which flattens the arch. Conversely, the FDB in a cavus foot would serve to actually increase the arch, and would have a ,mild adductory moment. Net result? A flattened transverse arch.

Now look at the Flexor digitorum longus, overactive in tbis foot (as evidenced by the flexion of the distal interphalangeal joints, mild adduction of the toes (due to the change of direction of pull in a cavus foot) and lowering of the met heads due to hyperextesnion at the MTP joints ). This mm is reciprocally linked with the extensor digitorum longus. The prominence of the extensor tendons is do to increased activity of the EDB (go ahead, extend all your fingers and look at the tendons in your hand. Now flex the  DIP and IP joints and extend the MTP; see how they become more prominent?).

Reciprocal inhibition. It’s not just for dinner anymore…

We are and remain; The Gait Guys

HIIT (high intensity exercise) and Parkinson's disease.

High intensity exercise may help to curb Parkinson's disease. Helping the gait riddle in this neurodegenerative disease.

Parkinsonian gait is a debilitating and challenging gait for anyone. Often catching this neurodegenerative disease early on bodes well for a client's outcome and quality of life in many respects. 60 thousand will be diagnosed with Parkinson's this year, and currently about 1 million live with the disease making this a very common disease. Parkinson's is a disorder of movement, of balance, talking, motor control, walking to name a few, so this is a very debilitating disease to most who experience it, either as a patient or as a care giver.

"A team of researchers at Northwestern Medicine and the University of Colorado School of Medicine wanted to find out whether high- or moderate-intensity exercise was safe for patients with Parkinson’s disease. Would it help with the disease’s symptoms, the progressive loss of muscle control, tremors, stiffness?"
"Five years later, those scientists have an answer: Yes. Increasing disease severity in early-stage Parkinson’s disease patients can be slowed with a few days of exercise weekly. The results of their trial, published Monday in JAMA Neurology, found vigorous exercise is a safe way to potentially delay the progression of Parkinson’s disease."

Here is the big question that the researchers proposed after the results of this study , "Is there any disease or any disorder for which exercise is not good?"

http://www.chicagotribune.com/lifestyles/health/ct-met-parkinsons-disease-progression-exercise-20171207-story.html

Thinking while walking changes arm swing...

Maybe we should keep this in mind while "gait retraining" and "rehabbing". You could be inducing the changes you are seeing on a cortical level. 

This makes you wonder about walking and thinking about sometime else. Being mindful has its advantages, like less cortical laterality and dominance. Remember, in this study, the arm swing is les on the right, so theoretically, less cortical motor drive from the left side. No wonder your gait changes! Be careful which hand you are texting with : )...Better yet, don't walk and text....

Human arm swing looks and feels highly automated, yet it is increasingly apparent that higher centres, including the cortex, are involved in many aspects of locomotor control. The addition of a cognitive task increases arm swing asymmetry during walking, but the characteristics and mechanism of this asymmetry are unclear. We hypothesized that this effect is lateralized and a Stroop word-colour naming task-primarily involving left hemisphere structures-would reduce right arm swing only. We recorded gait in 83 healthy subjects aged 18-80 walking normally on a treadmill and while performing a congruent and incongruent Stroop task. The primary measure of arm swing asymmetry-an index based on both three-dimensional wrist trajectories in which positive values indicate proportionally smaller movements on the right-increased significantly under dual-task conditions in those aged 40-59 and further still in the over-60s, driven by reduced right arm flexion. Right arm swing attenuation appears to be the norm in humans performing a locomotor-cognitive dual-task, confirming a prominent role of the brain in locomotor behaviour. Women under 60 are surprisingly resistant to this effect, revealing unexpected gender differences atop the hierarchical chain of locomotor control.

R Soc Open Sci. 2017 Jan 25;4(1):160993. doi: 10.1098/rsos.160993. eCollection 2017 Jan.
Increasing cognitive load attenuates right arm swing in healthy human walking.
Killeen T1, Easthope CS1, Filli L2, Lőrincz L2, Schrafl-Altermatt M1, Brugger P2, Linnebank M3, Curt A1, Zörner B1, Bolliger M1.

free full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5319362/

Arm swing and instability. To train or not to train... Should we do it?

We have long talked about arm swing and whether to change it, encourage it or just observe it. It appears to be an indicator of potential instability as well as a portent for more dire neurological problems (Alzheimers, Parkinson's)

This study looks at altered arm swing in kids with CP; how it is an indicator that there is a problem and how it can profoundly effect their gait and stability. Cerebral palsy may be an extreme case, but how does it differ REALLY (other than severity) from someone who has a mild neurological impairment, such as movement patterning disorders, that we see each and every day in our friends, family, clients and patients? Try and think out of the box and investigate the implications.

"Observational research suggests that in children with cerebral palsy, the altered arm swing is linked to instability during walking. Therefore, the current study investigates whether children with cerebral palsy use their arms more than typically developing children, to enhance gait stability. Evidence also suggests an influence of walking speed on gait stability. Moreover, previous research highlighted a link between walking speed and arm swing. Hence, the experiment aimed to explore differences between typically developing children and children with cerebral palsy taking into account the combined influence of restricting arm swing and increasing walking speed on gait stability. Spatiotemporal gait characteristics, trunk movement parameters and margins of stability were obtained using three dimensional gait analysis to assess gait stability of 26 children with cerebral palsy and 24 typically developing children. Four walking conditions were evaluated: (i) free arm swing and preferred walking speed; (ii) restricted arm swing and preferred walking speed; (iii) free arm swing and high walking speed; and (iv) restricted arm swing and high walking speed. Double support time and trunk acceleration variability increased more when arm swing was restricted in children with bilateral cerebral palsy compared to typically developing children and children with unilateral cerebral palsy. Trunk sway velocity increased more when walking speed was increased in children with unilateral cerebral palsy compared to children with bilateral cerebral palsy and typically developing children and in children with bilateral cerebral palsy compared to typically developing children. Trunk sway velocity increased more when both arm swing was restricted and walking speed was increased in children with bilateral cerebral palsy compared to typically developing children. It is proposed that facilitating arm swing during gait rehabilitation can improve gait stability and decrease trunk movements in children with cerebral palsy. The current results thereby partly support the suggestion that facilitating arm swing in specific situations possibly enhances safety and reduces the risk of falling in children with cerebral palsy."

Front Hum Neurosci. 2016 Jul 15;10:354. doi: 10.3389/fnhum.2016.00354. eCollection 2016.
Restricted Arm Swing Affects Gait Stability and Increased Walking Speed Alters Trunk Movements in Children with Cerebral Palsy.
Delabastita T, Desloovere K, Meyns P.

link to FREE FULL TEXT: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4945643/

Pod 136: Part 2: Head over Foot? Where should we put our COM (center of mass)?

This podcast (135) and its soon to launch follow up podcast (136), as the intro explains, comes at the tail end of a series of thought debates between Shawn and Ivo with some folks who have a different view point.  While the debate is unsettled because there is not sufficient research to support one side, we feel the research leans towards our side of things.  However, as the debates went on, it became clear to us that both parties were approaching the debate from a different metric to gauge each party's beliefs.  We outline this in the introduction and then more forward into our dialogue.  We hope you find this a productive thought experiment.

Key words: cross over gait, head over foot, HOF, gait, gait analysis, COM, COP, center of mass, center of pressure, step width, sprinting, symmetry, running injuries

Links to find the podcast:

iTunes page: https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138?mt=2

Direct Download: http://traffic.libsyn.com/thegaitguys/pod_136final.mp3

Permalink URL: http://thegaitguys.libsyn.com/pod-136-part-2-head-over-foot-where-should-we-put-our-com-center-of-mass

Libsyn URL:http://directory.libsyn.com/episode/index/id/6586622

Our Websites:
www.thegaitguys.com

summitchiroandrehab.com doctorallen.co shawnallen.net

Our website is all you need to remember. Everything you want, need and wish for is right there on the site.
Interested in our stuff ? Want to buy some of our lectures or our National Shoe Fit program? Click here (thegaitguys.com or thegaitguys.tumblr.com) and you will come to our websites. In the tabs, you will find tabs for STORE, SEMINARS, BOOK etc. We also lecture every 3rd Wednesday of the month on onlineCE.com. We have an extensive catalogued library of our courses there, you can take them any time for a nominal fee (~$20).

Our podcast is on iTunes and just about every other podcast harbor site, just google "the gait guys podcast", you will find us.

Evolution and gait.

We have discussed similar things in podcast a year or two ago. Being taller and leaner had advantages, we could see over the savanna grasses and we were better adapted to persistence running long distances with longer legs and a leaner build.

This Newsweek article discusses the suspected behaviorally driven 1.5 million year ago growth spurt helping us grow taller and lankier.

"An increase solely in stature would have created a leaner physique, with long legs and narrow hips and shoulders,” said lead author from Cambridge Manuel Will, according to Phys.org. “This may have been an adaptation to new environments and endurance hunting, as early Homo species left the forests and moved on to more arid African savannas."

And as we discussed when reviewing a Radiolab podcast, the taller and more hairless the person, the more surface area for heat radiation/sweating to keep us cooler during these persistence runs for big game food.

And with these growth changes, of course, our gait had to have changed.

http://www.newsweek.com/early-humans-became-tall-and-thin-15-million-years-ago-survive-outside-forest-705678

wider, flatter, less mobile feet

If you have patella femoral pain, the older you get, the wider (probably for increased proprioception), flatter (possibly due to loss of intrinsic strength and extensor tone) and less mobile (for stability) you feet become. 

"This study observed that in individuals with PFP, those aged 40–50 years had less foot mobility than younger adults aged 18–29 years, as evidenced by measures of midfoot height mobility and foot mobility magnitude. These differences represented a moderate effect size, and exceed the intra-rater minimal detectable change (MDC 95%) associated with these measures (midfoot height mobility 2 mm; foot mobility magnitude 3.1 mm). The differences between age groups were specific to both midfoot height mobility and foot mobility magnitude; however, there were no differences in midfoot width mobility."

Tan JM, Crossley KM, Vicenzino B, Menz HB, Munteanu SE, Collins NJ. Age-related differences in foot mobility in individuals with patellofemoral pain. Journal of Foot and Ankle Research. 2018;11:5. doi:10.1186/s13047-018-0249-2.

free full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5815185/

Footwear IS Medicine

We always have said that "Shoes ARE medicine" Here's an article that supports that.

"Footwear plays an integral role in force distribution on the lower extremities, and choosing appropriate footwear is one of many strategies people can use to manage knee pain caused by joint disorders. When footwear is properly fit, force and stress can be shifted away from weaker parts of the knee, and the leg stabilized. This may lead to a significantly better quality of life for patients with knee problems, such as osteoarthritis (OA) and patellofemoral pain syndrome."

http://lermagazine.com/article/the-effect-of-footwear-on-the-management-of-pain-caused-by-disorders-of-the-knee-joint

Slipped capital femoral epiphysis

Slipped captial femoral epiphysis and gait.

Yesterday in the clinic a young teenager was brought into the office with a gait problem. Or so it seemed. The patient was walking with a "peg legged" locked knee gait on the right side. It was as if she was wearing a straight leg knee immobilizer. There was no knee bend during gait, she was not in much pain. A month prior, when the problem started, she recalls "straining" the right thigh during tennis. There was a sudden sharp jabbing pain in the mid thigh, and over the next 2 days , much thigh and lateral hip pain. Radiographs of the femur were unremarkable by another doctor. Physical therapy exercises by another facility have been fruitless.
On the exam table there was a terrible pelvis distortion pattern and the affected leg looked, no kidding, 1 inch longer on the table. The knee and quad during exam were splinted, she did not want the knee bent. or so I thought.
As the exam went on, it became clear that it was not the knee that did not want bent, it was hip flexion that she did not want, she was just unaware it was the hip, because the pain would only come on into the thigh during the exam.
I proceeded to gently press over the anterior femoral head, and she screamed.

This is a SCFE until proven otherwise. This was a 13 year old, with sudden onset of thigh pain after an abrupt load. I have seen this a few times in practice, and they have often presented in just this manner. Growth plates have to be high on the list in teenagers, especially when pain remains ongoing, and there are extraordinary joint splinting and compensations such as in her gait. She was clearly splinting through the quads, in an attempt to completely unload the gluteal generated hip joint compression. She could not activate or contract her quadriceps, at all ! She wanted no part of compression or load across this hip joint. The locked knee gait was her attempt to depend on more quad generated hip/limb stability during loading.

If you are training or treating teens, the growth plate always has to be on the differential diagnosis list.
* this is not her radiograph above, i am still waiting to hear from someone.

Gait Posture. 2017 Oct;58:358-362. doi: 10.1016/j.gaitpost.2017.08.026. Epub 2017 Aug 26.
Gait deviations in transverse plane after SCFE in dependence on the femoral offset. Hummel S1, Rosenthal D2, Zilkens C2, Hefter H2, Krauspe R2, Westhoff B2.

Better gait = better cognition = Better gait

use it or lose it....

"This study demonstrates that cognitive flexibility is associated with walking, in particular under challenging walking conditions, in a cohort of older adults without relevant motor and cognitive deficits. We also demonstrated that older individuals with poor cognitive flexibility use a pattern in variability-related gait parameters across walking conditions that differs from individuals with good cognitive flexibility. This difference might indicate a lower capability of the former population to adapt to challenging walking situations with different demands. Our findings add relevant information to our understanding of gait and balance deficits in older adults with poor cognitive flexibility and may give a basis for interventional studies."

FREE full text available here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5442228/