The Glute Max does that?

-There’s lots of talks about glutes and glute function. When was the last time you thought about the gluteus maximus has an internal rotator of the hip? We did a recent podcast and talked about this during climbing. 

-As the thigh flexes to 90° or greater, the internal rotational power of both the gluteus maximus and medius increases exponentially. Think about this when prescribing your rehabilitation exercises and get creative!

For a lot more information on this as well as other fun things with the glutes join us tomorrow evening for our monthly third Wednesdays Teleseminar on onlinece.com biomechanics 328 tomorrow night, 7 central 

Come join us for an hour of talking about peoples butts and how to make them work better :-)

#gluteus #gluteusmaximus #glute #glutes #muscleaction #muscleactions #rehab #rehabilitation #exercise #gluteexercise #gluteexercises 

Podcast 164: Foot placement challenges, vestibular issues & spatial orientation.

Podcast 164:  Foot placement challenges, vestibular issues & spatial orientation.

This podcast is way more interesting than the title !

join us each month on the Masterclass in Gait

https://www.patreon.com/thegaitguys

Join at the $40 monthly level and get the masterclass each month, bonus material and the detailed monthly content we only share on Patreon.

The Masterclass is a formal LIVE presentation of slides, videos, demos, deep dives on topics you will not hear anywhere but here ! We hit the gait, biomechanics, neurology and orthopedics of all of the gait topics we present. This is not for the weak and timid, this is the deep dive you have been waiting for. Join us while we turn our normal 50 minute presentations into 3.5 hours on a regular basis ! The 40$ Patreon level will give you the Masterclass and also get you the $20, $10, and 5$ Patreon level content. What a deal ! It will not be here forever so lock in now !

Or, you can get less for your money (why would you do that?) and just buy our Monthly $40 Masterclass at our VIMEO on demand page: https://vimeo.com/ondemand/thegaitmasterclass


Links to find the podcast:
Look for us on Apple Podcasts, Google Play, Podbean, PlayerFM, RADIO and more.
Just Google "the gait guys podcast".
_______________________________________________________________________________
Our Websites:
www.thegaitguys.com
Find Exclusive content at: https://www.patreon.com/thegaitguys
doctorallen.co
summitchiroandrehab.com
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.

Where to find us, the podcast Links:
Apple podcasts:
https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138?mt=2

Google Play:

https://play.google.com/music/m/Icdfyphojzy3drj2tsxaxuadiue?t=The_Gait_Guys_Podcast

https://traffic.libsyn.com/secure/thegaitguys/Pod_164_was_pod_162_May_25_-_81520_6.20_PM.mp3

https://thegaitguys.libsyn.com/foot-placement-challenges-vestibular-issues-spatial-orientation

https://directory.libsyn.com/episode/index/id/15625700

The unhappy triad

The unhappy triad?

-internal tibial torsion, femoral retro torsion, tibial varum. We often see these three things occurring together which can create patellar tracking problems or, as in this lower back pain. We know that things often occur in threes and congenital abnormalities are no different. 

–The femoral retro torsion limit internal rotation of the hip so when that foot is planted on the ground, the patient rotates to that side, the hip stops and the lumbar spine keeps going. 

–The lumbar spine should only have about 5° of rotation from top to bottom so this often puts undue stress into the lumbar spine resulting in lower back pain.

The remedy?

– Things which we can do to utilize or help internal rotation of the hips such as chair exercises with internal rotation, the 90/90 seated stretch as well as patient education to keep shoulders and hips in the same plane when rotating or carrying a load as well as externally rotating the foot when spinning to that side (To create the range of motion that is not available).

#itt #internaltibialtorsion #internaltibialrotation #femoralretroversion #femoralretrotorsion #limitedhipmotion #gait #tibialvarum 

What happens when a ganglionectomy goes south

What happens when a ganglionectomy goes south?

- This patient had a ganglionectomy. Unfortunately, they tagged the joint capsule of the first MTP. By affecting the integrity of the capsule, as well as the surrounding musculature, she’s developed the beginnings of a hallux valgus (bunion) as well as hallux limitus (limited dorsiflexion of the first metatarsalphalangeal articulation). 

- she has degeneration of the first MTP as well as an osteophytic  crown at the distal aspect of the first metatarsal and tenderness over the capsule as well as the extensor hallucis tendon and proximal phalanx. 

-dorsiflexion is 30° on this side, 50 on the opposite side. We need about 50° to have adequate for foot rocker

– she also has moderate external tibial torsion, right greater than left and a left anatomically short leg secondary to a femur fracture.

– Since the mobility of the first ray was limited, we worked on first Ray mobility as well as exercises to descend the 1st ray, with acupuncture for pain control. 

-we are considering an orthotic to assist in raising the base and dropping the head of the first metatarsal to create more hallux dorsiflexion. When performed manually, she had a few extra degrees we would like to take advantage of. 

-We will keep you posted :-)

#ganglionectomy #footproblem #footproblems #halluxlimitus #bigtoewoes #bunion #bunions #bunionsurgery 

Parkinson's and Gait

Are gait changes predictive of Parkinson’s disease?

-We have all seen people with this slowing, festination type gait in our practices. Parkinson’s disease or Parkinson spectrum is due to degeneration of a dopaminergic pathway in your brain stem called the nigiostriatal pathway between the substantia nigra and corpus striatum of the basil ganglia. You probably remember that the basil ganglia is responsible for coordination of movement and background positioning of joints to superimpose motion on top of.

-A recent paper talks about gait changes; observing 14 different parameters and guess what? 

- Gait changes pre-dated Parkinson’s onset by about 4 to 5 years. The largest changes were in gait asymmetry including step length and speed of motion.

-The real question becomes “are these changes inevitable or are they preventable with appropriate therapy?“ 

–we think so, largely because of the brains amazing abilities and neural plasticity. Rehab has a cognitive component that we feel is just as important as the exercise component.

#parkinsons #gait  #parkinsonsdisease #clinicalexam #predictivefactors 

Del Din S, Elshehabi M, Galna B, et al. Gait analysis with wearables predicts conversion to parkinson disease. Ann Neurol. 2019;86(3):357-367. doi:10.1002/ana.25548

Stretching part 2

So, how can we utilize this reflex? 

How about to activate a weak or lengthened muscle?

Did you notice the other neuron in the picture? There is an axon collateral coming off the Ia afferent that goes to an inhibitory interneuron, which, in turn, inhibits the antagonist of what you just stretched or activated. So if you acitvate one muscle, you inhibit its antagonist, provided there are not too many other things acting on that inhibitory interneuron that may be inhibiting its activity. Yes, you can inhibit something that inhibits, which means you would essentially be exciting it. This is probably one of the many mechanisms that explain spasticity/hypertonicity

How can we use this? How about to inhibit a hypertonic muscle?
Lets take a common example: You have hypertonic hip flexors. You are reciprocally inhibiting your glute max. You stretch the hypertonic hip flexors, they become more hypertonic (but it feels so good, doesn’t it?) and subsequently inhibit the glute max more. Hmm. Not the clinical result you were hoping for?
How about this: you apply slow stretch to the glutes (ie “reverse stretch”) and apply pressure to the perimeter, both of which activate the spindle and make the glutes contract more. This causes the reciprocal inhibition of the hip flexors. Cool, eh? Now lightly contract the glutes while you are applying a slow stretch to them; even MORE slow stretch; even MORE activation. Double cool, eh?

Don’t believe me, try this on yourself, your clients, patients, willing family members and pets.

Image credit: https://commons.wikimedia.org/wiki/File:The_extensor_digitorum_reflex.jpg

Stretching part 1

Stretching secrets you need to know

OK, maybe they aren’t secrets, but these are some ‘shortcuts” you should know. 

We know from studies out there that static stretching can lengthen muscle (actually add sarcomeres), but you need to do it 30 minutes per day per muscle group. How about something a little faster doc?

How about taking advantage of the stretch reflex and reciprocal inhibition; or the “reverse stretch”

Reciprocal inhibition is a topic we have spoken about before on our blog, social media and our PODcasts. 1st described in1923 by Sherrington, this diagram sums it up nicely. Note the direct connection from the spindle to the alpha motor neuron, which is via a Ia afferent fiber. When the spindle is stretched, and the pathway is intact, the muscle will contract. This its a straight forward stretch or inverse myotatic reflex. 

Remember, ANY kind of stretch or anything that changes the length of the spindle will effect it. So what happens when you do a nice, long, slow stretch? You ACTIVATE the spindle, which activates the alpha motor neuron. If you stretch long enough, you may fatigue the reflex. So why do we give folks long, slow stretches to perform? Good question! Certainly not to “relax” the muscle!

So, how can we utilize this reflex? Read our next post tomorrow!



Image credit: https://commons.wikimedia.org/wiki/File:The_extensor_digitorum_reflex.jpg

Hills for training

The top five reasons we like Hills for training ankle rocker and hip extension

1. Hills do not cost money and are almost always readily available

2. Hills do not pull the hip into extension and place of stretch on the anterior hip musculature including the rectus femoris, iliopsoas and iliacus. This causes a slow stretch of the muscle activating the muscle spindles and causing muscle contraction via the stretch reflex. This will inhibit the posterior compartment of hip extensors through reciprocal inhibition, making it difficult to fire them.

3. A hill does not force your knee into extension, eliciting a stretch reflex in the hamstrings like a treadmill does

4. A hill naturally puts the ankle into dorsiflexion, And, along with active pulling up of the toes, helps you to get more into your anterior compartment and limits the tendency of the ankle being pulled into dorsiflexion (like a treadmill) which would initiate a stretch reflex in the gastroc/soleus and long flexors for the toes

5. The increased hip flexor recruitment of going uphill gives you more opportunity to engage your abs before the psoas and rectus femoris/TFL and, on the stance phase leg, you can get an increased stretch of those muscles

#hill #hills #rehab #rehabilitation#runningupthathill #runninghills#ankledorsiflexion #anklerocker#hipextension

Podcast 163: The hip and foot talk to each other. A research paper.

You cannot miss this mini-podcast. It is an excerpt from our Masterclass program. Come join us monthly on the Masterclass at for the monthly Masterclass installment hour.

https://www.patreon.com/thegaitguys

Formal presentations, slides, videos, demos, deep dives on topics you will not hear anywhere but here ! We hit the gait, biomechanics, neurology and orthopedics of all of the gait topics we present. This is not for the weak and timid, this is the deep dive you have been waiting for. Join us while we turn our normal 50 minute presentations into 3.5 hours on a regular basis ! The 40$ Patreon level will give you 50% off the Masterclass and also get you the $20, $10, and 5$ Patreon level content. What a deal ! It will not be here forever so lock in now !

Or, you can get less for your money (why would you do that?) and just buy our Monthly Masterclass at our VIMEO page: https://vimeo.com/ondemand/thegaitmasterclass


Links to find the podcast:
Look for us on Apple Podcasts, Google Play, Podbean, PlayerFM, RADIO and more.
Just Google "the gait guys podcast".
_______________________________________________________________________________
Our Websites:
www.thegaitguys.com
Find Exclusive content at: https://www.patreon.com/thegaitguys
doctorallen.co
summitchiroandrehab.com
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.

Where to find us, the podcast Links:
Apple podcasts:
https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138?mt=2

Google Play:

https://play.google.com/music/m/Icdfyphojzy3drj2tsxaxuadiue?t=The_Gait_Guys_Podcast

Other locations:

https://traffic.libsyn.com/secure/thegaitguys/163_mini_pod_peronei_-_8120_12.01_PM.mp3

https://thegaitguys.libsyn.com/the-hip-and-foot-talk-to-eachother-really-a-research-paper

https://directory.libsyn.com/episode/index/id/15439292

Today's article link: https://pubmed.ncbi.nlm.nih.gov/32717719/

Podcast 162: Climbing and gait

Podcast Guest today: Dr. Nick Hedges from Summit Chiropractic and Rehab summitchiroandrehab.com

*The Masterclass in Gait, with the Gait Guys

join us monthly at: https://www.patreon.com/thegaitguys for the monthly Masterclass installment hour. Formal presentations, slides, videos, demos, deep dives on topics you will not hear anywhere but here ! We hit the gait, biomechanics, neurology and orthopedics of all of the gait topics we present. This is not for the weak and timid, this is the deep dive you have been waiting for. Join us while we turn our normal 50 minute presentations into 3.5 hours on a regular basis ! The 40$ Patreon level will give you 50% off the Masterclass and also get you the $20, $10, and 5$ Patreon level content. What a deal ! It will not be here forever so lock in now !

Or, you can get less for your money and just buy our Monthly Masterclass at our VIMEO page: https://vimeo.com/ondemand/thegaitmasterclass


Links to find the podcast:
Look for us on Apple Podcasts, Google Play, Podbean, PlayerFM, RADIO and more.
Just Google "the gait guys podcast".
_______________________________________________________________________________
Our Websites:
www.thegaitguys.com
Find Exclusive content at: https://www.patreon.com/thegaitguys
doctorallen.co
summitchiroandrehab.com
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.

Where to find us, the podcast Links:
Apple podcasts:
https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138?mt=2

Google Play:
https://play.google.com/music/m/Icdfyphojzy3drj2tsxaxuadiue?t=The_Gait_Guys_Podcast

Links to find today's show:
https://traffic.libsyn.com/secure/thegaitguys/pod_161_Climbing_final_-_72620_5.40_PM.mp3

https://thegaitguys.libsyn.com/gait-and-rock-climbing

https://directory.libsyn.com/episode/index/id/15367754

Malleolar Fracture

What does a post lateral malleolar fracture patient look like?

Can you say loss of proprioception? Can you say loss of triceps surae strength? Can you say loss of hip abductor strength?

Whenever we have a fracture and that segment is subsequently immobilized, we usually have damage to joint and muscle Mechanoreceptors as well as some atrophy of the receptors because of the immobilization. Lucky for us, and this patient in particular, those changes are rapidly reversed due largely to initially neural adaptation which is responsible for most of the early strength changes and then later, after a few weeks, muscular hypertrophy.

Callouses Happen

Calluses happen when we have too much pressure over an area of skin, creating friction for too long of a time. The keratinocytes produce excess keratin and you are looking at the result. We can tell from this picture is that this girl definitely has a problem under her 2nd/3rd met area as well as a pinch callous at the distal aspect of the distal phalanx of the hallux.

This particular patient had a wedge osteotomy surgery performed for her bunion which altered the mechanics of her second toe causing an actually to move dorsally and the callous you were seeing is from the distal head of the third metatarsal. Because she has external tibial torsion and because of the bunion, she externally rotates the lower extremity during push off creating friction at the distal aspect of the phalanx. Paragraph calluses or clues. When you see them, start investigating :-)

What does progressive weakness of the posterior compartment look like?

Look at this video carefully and what do you notice? Can you see the progressive dip in the left heel as time goes on while toe walking? This is a cardinal sign of lack of endurance in the posterior compartment, in this patient’s case tibialis posterior. Your differential, in addition to lack of type one muscle fibers, insufficient vascularity or mitochondria for whatever reason would be circulatory problems as well as conditions causing progressive motor weakness like myasthenia gravis.

Fatigue testing is very important because a lot of times the problem doesn’t come out till the person reaches say a half an hour, an hour or sometimes even many miles into the run or ride. Our job as clinicians is to try to diagnose the problem to the best of our abilities. Our job also is to “exploit their weaknesses” rather than “extol their virtues”. 

If you’re getting somebody with posterior calf pain or a foot drop, or maybe somebody who gets worse over time, consider fatigue testing.

Valgus Posts

A valgus post on an orthotic is a useful tool when you are trying to get weight off of the lateral and onto the medial column of the foot. It works best with people that have adequate range of motion in the first ray complex (they can get the head of the big toe to the ground) because if you don’t have adequate range of motion, you will only force the knee to the midline which sometimes can cause patellofemoral problems.

A valgus post as a post which begins wider laterally and narrows medially. It usually begins near the tubercle of the fifth metatarsal and can extend as far up as the end of the fifth toe. The idea is as you walk across the post, it forces the foot from lateral to medial helping to sink the first ray down to the ground. It functions similar to a first ray cut out (A notch cut out of the orthotic at the head of the first metatarsal) however is generally more gradual and sometimes better tolerated.

This type of posting is often used in people with internal tibial torsion who often having a difficult time getting weight onto the first right and keeping the knee in the sagittal plane.

In this video we briefly describe how the posting works. 

Is there a need for "Gait Retraining'?...We think so

Some hip OA patients walk the way they do because of pain, actually most do because of the pain.  In doing so, they alter loading patterns. As we discussed last week in podcast 161 (Central Pattern Generators) over time this re-wires a central pattern generator, and we get new automated plastic loops of neurologic recruitment. If hip OA patients in pain can do this, so can you, in fact you will. In fact, you already have in many ways if you are a few decades into your life.

“This study below (3) documents alterations in hip kinematics and kinetics resulting in decreased hip loading in patients with hip OA. The results suggested that patients altered their gait to increase medio-lateral stability, thereby decreasing demand on the hip abductors. These findings support discharge of abductor muscles that may bear clinical relevance of tailored rehabilitation targeting hip abductor muscles strengthening and gait retraining.”

There seems to be some controversy with regards to gait retraining. Some folks seem to believe that it should be “left to itself” and they are fully compensated already (1). Perhaps this is true…or not. We have not seen any studies that compare gait retraining vs non gait retraining as a whole, but there seems to be plenty for specific conditions (2). We all see folks AFTER THE FACT and seek to correct the problems and reverse, halt or slow the progression of further pathology. That seems to be what many of us do.

There is substantial evidence that hip pathomechanics lead to osteoarthritis (4, 5). Wouldn’t it make sense to assist in altering motor patterns and correct those biomechanical faults before it becomes a problem? Lets change our focus (if we haven’t already) and concentrate on skill, endurance and strength, in that order for the betterment of ourselves, our patients and humanity.

Meyer CAG, Wesseling M, Corten K, Nieuwenhuys A, Monari D5, Simon JP, Jonkers I, Desloovere K. Hip movement pathomechanics of patients with hip osteoarthritis aim at reducing hip joint loading on the osteoarthritic side. Gait Posture. 2018 Jan;59:11-17. doi: 10.1016/j.gaitpost.2017.09.020. Epub 2017 Sep 22.

image source: https://commons.wikimedia.org/wiki/File:Severe_(Tönnis_grade_3)_osteoarthritis_of_the_hip.jpg

full references, links to free full text on the blog: https://www.thegaitguys.com/thedailyblog/2018/9/12/is-there-a-need-for-gait-retrainingwe-think-so

Cortical Repatterning

Cortical Repatterning

We have been talking this week about what we all cortical repatterning or “motor programming”. Here I run through simple marching exercise for a patient with dystopia, giving some salient points and cues along the way.

A simple test for motor programming

Marching, a rudimentary motion, is a great screening for people with motor programming difficulties. This gal has left lower extremity dystonia and we were looking to see if it was more peripheral or central in origin.

You can see how her movement breaks down after a few simple steps of attempted coordinated movement. Use this simple marching screen next time you suspect a central programming issue in your patients :-) 

Podcast 161: Central pattern generators: Why and how movement goes bad

Hello, World!

*The Masterclass in Gait, with the Gait Guys

join us monthly at: https://www.patreon.com/thegaitguys for the monthly Masterclass installment hour. Formal presentations, slides, videos, demos, deep dives on topics you will not hear anywhere but here ! We hit the gait, biomechanics, neurology and orthopedics of all of the gait topics we present. This is not for the weak and timid, this is the deep dive you have been waiting for. Join us while we turn our normal 50 minute presentations into 3.5 hours on a regular basis ! The 40$ Patreon level will give you 50% off the Masterclass and also get you the $20, $10, and 5$ Patreon level content. What a deal ! It will not be here forever so lock in now !

Or, you can get less for your money and just buy our Monthly Masterclass at our VIMEO page: https://vimeo.com/ondemand/thegaitmasterclass

Links to find the podcast:
Look for us on Apple Podcasts, Google Play, Podbean, PlayerFM, RADIO and more.
Just Google "the gait guys podcast".
_______________________________________________________________________________
Our Websites:
www.thegaitguys.com
Find Exclusive content at: https://www.patreon.com/thegaitguys
doctorallen.co
summitchiroandrehab.com
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.

Where to find us, the podcast Links:
Apple podcasts:
https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138?mt=2

Google Play:
https://play.google.com/music/m/Icdfyphojzy3drj2tsxaxuadiue?t=The_Gait_Guys_Podcast

Links to find today's show:
https://traffic.libsyn.com/secure/thegaitguys/pod._163_June_21_-_62120_9.41_AM.mp3
https://thegaitguys.libsyn.com/central-pattern-generators-why-and-how-movement-goes-bad-0
https://directory.libsyn.com/episode/index/id/14905823

Calf Size Matters

Calf size matters. Truly, and here is why.

The Achilles tendon (AT) moment arm transforms triceps surae muscle forces into a moment about the ankle which is critical for functional activities like walking and running. The achilles tendon moment arm changes continuously during walking. It changes as movement occurs and as the triceps surae contracts. But, it also changes as the muscle grows in size, or shrinks. This has relevance to exercise, strengthening, and atrophy of the calf compartment. When the muscle contracts, its cross sectional area changes, and this can change the pull angle on the achilles. One might think of the achilles tendon as being "tented" away from the tibia slightly, and one can feel this on their own foot when palpating the soft tissue space between the tendon and the tibia on plantarflexion even when sitting. Better yet, sit down, your foot on the ground. Now, palpate the soft tissue space between the achilles and tibia. Now raise your heel, thus forefoot loading. You will feel the space gap open, the moment arm has increased because of this, thus changing its moment arm. On dorsiflexion the moment arm shortens, on plantarflexion it lengthens. Sure, this does not create a monstrous line of pull change, but by the time we get down to the pivot point at the ankle mortise, a small change in moment arm can translate to significant changes in torque and force production. This is why a foot that does not supinate in time for heel off, or supinate sufficiently, meaning the rear foot isn't inverted optimally, means that the ankle mortise (talus position) might change/shorten that moment arm. This is not efficient mechanics. Want to jump higher ? You have to get that excessive pronation in ankle dorsiflexion under control and convert it to supination, and rearfoot inversion. Jumping from a collapsed foot tripod is a power leak and you will not optimize the triceps surae-achilles complex and their lever arm. This also goes for toe off in walking and especially running, particularly sprinting where you are up on that forefoot. Said another way, when the arch is more collapsed and the talus is thus more plantarflexed the moment arm is sorter for the achilles. Strength, power, torque all suffer. One does not want to engage heel rise and calf contraction from this ineffective position of pronation taken too far, or heel rise while still pronated. This can also put undue load, and angle of pull, through the achilles. Meaning, the linear pull one desires through the achilles, can be through a calcaneal insertion that is not oriented optimally. One might postulate, rightly so we believe, that the lateral bundles/fascicles of the achilles tendon might see more loading than the medial. At the very least, we might postulate that the medial and lateral achilles tensile loads are offset and unequal. This could create problems over time, meaning changes in tendon morphology.

In the below Rasske & Franz article, they posit that aging negatively effects the architecturally complex AT moment arm during walking, which thereby contributes to well-documented reductions in ankle moment generation during push-off. They looked at the "AT moment arms of young (23.9 ± 4.3 years) and older (69.9 ± 2.6 years) adults during walking, their dependence on triceps surae muscle loading, and their association with ankle moment generation during push-off. Older adults walked with 11% smaller AT moment arms and 11% smaller peak ankle moments during push-off than young adults. Moreover, as hypothesized, these unfavourable changes were significantly and positively correlated (r2 = 0.38, p < 0.01). More surprisingly, aging attenuated load-dependent increases in the AT moment arm (i.e., those between heel-strike and push-off at the same ankle angle); only young adults exhibited a significant increase in their AT moment arm due to triceps surae muscle-loading. Age-associated reductions in triceps surae volume or activation, and thus muscle bulging during force generation, may compromise the mechanical advantage of the AT during the critical push-off phase of walking in older adults. Thus, strategies to restore and/or improve locomotor performance in our aging population should consider these functionally important changes in musculoskeletal behavior."

Great article spawning deeper thoughts, here at The Gait Guys blog.
More to come on this most likely.

Aging effects on the Achilles tendon moment arm during walking. Kristen Rasske, Jason R.Franz
Journal of Biomechanics
Volume 77, 22 August 2018, Pages 34-39

Photo credit: Image by Huei-Ming Chai, National Taiwan University School of Physical Therapy as found on www.runsmartproject.com

The Calcaneo Cuboid Locking Mechanism

Do you know what this is? You should if you walk or run!

It is the mechanism by which the tendon of the peroneus longus travels behind the lateral malleolus of the ankle, travels underfoot, around the cuboid to insert into the lateral aspect of the base of the 1st metatarsal and adjacent 1st cunieform.

When the peroneus longus contracts, in addition to plantar flexing the 1st ray, it everts the cuboid and locks the lateral column of the foot, minimizing muscular strain required to maintain the foot in supination (the locked position for propulsion). Normally, muscle strength alone is insufficient to perform this job and it requires some help from the adjacent articulations.

In addition, the soleus maintains spuination during propulsion by plantar flexing and inverting rear foot via the subtalar joint. This is assisted by the peroneus brevis and tertius which also dorsflex and evert the lateral column, helping keep it locked. Can you see why the peroneii are so important?

Signs of a faulty calcaneo cuboid locking mechanism:

-weak peroneus longus, brevis and or tertius

-excessive rear or midfoot pronation

-low arch during ambulation-poor or low gear “push off”

-subluxated cuboid

The calcaneo cuboid locking mechanism. Essential for appropriate supination and ambulation. Insufficiency, coming to a foot you will soon examine.

Would you like to know more? Join us for our “third Wednesdays“ online webinar: Biomechanics 313. Wednesday, June 18 at 6 MST. Onlinece.com