Podcast 106: Understanding Tendonopathies & Asymmetrical Bone density in athletes.

* Plus the global effects of Hallux Limitus, & Chronic exposure to routine high-impact, gravitational loads afforded to the support limb preferentially improved bone mass and structure

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Other Gait Guys stuff

2 Podcast links: 



B. iTunes link:

C. Gait Guys online /download store (National Shoe Fit Certification & more !)

D. other web based Gait Guys lectures:
Monthly lectures at : www.onlinece.com type in Dr. Waerlop or Dr. Allen, ”Biomechanics”

-Our Book: Pedographs and Gait Analysis and Clinical Case Studies
Electronic copies available here:


-Barnes and Noble / Nook Reader:


-Hardcopy available from our publisher:


Show Notes:

New device to get people with paralysis back on their feet
Scientists have tested the world’s first minimally-invasive brain-machine interface, designed to control an exoskeleton with the power of thought

Splicing out torsions, and aberrant foo types ? Club foot ? etc

Scientists Capture Crispr’s Gene-Cutting in Action

The UK Just Green-Lit Crispr Gene Editing in Human Embryos

Asymmetries in limbs

Tension or compression ?
link to full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3676165/

Concept: the forces have to go somewhere, it is a “passing the buck” system.  
We did this blog post here to explain:

The new muscle discovery !

tendinopathy vasculature: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4650849/

tendinopathy treatment paper: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2505250/

Got big toe pain? Think it’s gout? Think again!   Things are not always what they appear to be. 

This gent came in with first metatarsophalangeal pain which had begun a few months previous. His uric acid levels were borderline high (6) so he was diagnosed with gout.  It should be noted his other inflammatory markers (SED rate and CRP) were low. Medication did not make the symptoms better, rest was the only thing that helped. 

The backstory is a few months ago he was running in the snow and “punched through"the snow, hitting the bottom of his foot on the ground. Pain developed over the next few days and then subsided. The pain would come on whenever he try to run or walk along distances and he noticed a difficult time extending his big toe.

 Examination revealed some redness mild swelling over the 1st metatarsophalangeal joint (see pictures above) and hallux dorsiflexion of 10°.   If we raised the base of the first metatarsal and pushed down on the head of the 1st, he was able to dorsiflex the 1st MTP approximately 50°. He had point tenderness over the medial sesamoid. We shot the x-rays you see above. The films revealed a fracture of the medial sesamoid with some resorption of the bone.

The  sesamoid fracture caused the head of the 1st metatarsal to descend on one side, and remain higher on the other, altering the axis of rotation of the joint and restricting extension. We have talked about the importance of the axis of this joint in may other posts (see here and here).

 He was given exercises to assist in descending the first ray (EHB, toe waving, tripod standing).  He will be reevaluated in a week and if not significantly improved we will consider a wedge under the medial sesamoid. 

A pretty straight forward case of “you need to be looking in the right place to make the diagnosis”. Take the time to examine folks and get a good history.

The Banana Toe: The Force has to go somewhere. It’s a Jedi Gait Rule.

* note: there are 4 photos to today’s blog post. Be sure you click through all 4.

When you toe off, you have to toe off from somewhere in the foot unless you like an apropulsive hip flexion gait, where  you just lift you foot off the ground from foot flat, kind of like a true neurologic “foot drop” gait client would.  But, if you are lucky enough not to have a true foot drop, you are going to push off somewhere in the foot.  You can do it off the lateral foot (low gear toe off) and lesser toes, or you can do it off the big toe (high gear) the way we were built to do it. 

The above pictures show a nasty dorsal crown of osteophytes that is limiting hallux (big toe) extension/dorsiflexion. This is true hallus rigidus and hallux limitus. When this client attempts to toe off, the joint cannot normally partake in the activity, there is no Windlass effect, no posturing up over the sesamoids for mechanical advantage etc.   

In this scenario, there are two places you can put it, up into the next proximal joint(s) meaning the met-cuneiform joint or further down into the interphalangeal joint. In other words. the loads go proximal or distal to the limited joint, and they eventually play out there, over and over and over gain. The former option would basically mean you are pronating/dorsiflexing through the midfoot which is never good (can you say Saddle exostosis ! ouch !) or the latter option is to dorsiflex through the interphalangeal joint  and over time that toe begins to attenuate plantar ligamentous structures and extend beyond its normal limits resulting in the “Chiquita” toe (a upward bent toe resembling a banana shape). This will disable the long flexor of the great toe (FHL: flexor hallucis longus).and inhibit mechanical advantage of the extensor digitorum brevis.  If you struggle with the “how and why” behind this sentence in terms of restoration attempts, you need to watch my video here. It will offer you deeper insights.

Will this toe become painful ? yes, in time it is quite possible.  Is there much you can do? Sure, a rocker bottomed shoe will help take the load at toe off instead of forcing it into this toe or the midfoot.  Will an orthotic  help ? Well, this is a loaded question. If you are putting the forces into the midfoot choice as described above, the orthotic will block that motion and you will likely default option into the toe presentation above. So you are merely just moving loading forces around. It can be helpful, but you are quite possibly “robbing Peter to pay Paul” as they say.  The video I asked you to watch can be helpful but it will force that metatarsophalangeal joint into extension, a range it does not have, so it is not a remedy and not recommended.  Perhaps some awareness and slight increase in FHL(long toe flexor) use can be attained however.  These are tricky cases, simple in theory, but execution can be fussy and requires patient awareness and education. We like the rocker bottomed shoe as a nice easy solution and some increased FHL use awareness.  Help them find a little more FHL use by putting a pencil under the crease of the toe and help them to drive the tip of the toe down just a little out of that banana extension posture. It can help them control the overloading of the dorsal aspect of the interphalangeal joint.

As always, lets carry this forward into gait thoughts.  How is  hip extension going to be in this client ? How is glute strength ? Hip joint range ? Hip extension motor patterning ? Will the client go into anterior pelvic tilt to borrow the last range of hip extension ? Will the hamstrings have to accommodate ? Lots of yummy biomechanical and neurological mental gymnastics here. Bottom line answer to all the above ?  “ it depends, they will have to accommodate and compensate”.  And as the Jedi Gait Rule goes, “the Force as to go somewhere”.

Shawn Allen, one of the gait guys

Yes, you are looking INSIDE this toe. That IS a screw and metal plate in that toe. 

What kind of stuff finds its way into your office ? I get all kinds of things it seems, at least once a day something comes in that makes me scratch my head. 

This client just wanted my opinion and thoughts on their toe and their gait once they are ambulating again. They have had multiple surgeries to this poor foot. You can see multiple scars over multiple digits and metatarsals.  This is the 3rd surgery to the big toe, the last 2 have been attempts at correcting failed prior surgeries. This is obviously the last straw surgery, total fusion of the metatarsophalangeal joint.  What is interesting in this case is that this plate was taken out about 4 weeks ago, and the skin was stretched back over and the wound closed up (forgot to take update photo for you). I saw it yesterday, and I was amazed at how healed up the area was. They are months post op now, and they can load the toe heavily now, that is always amazing to me. The body’s healing ability is a miracle. Of course, if you have been with us here long enough you will know that my “concern button” immediately got pushed but the client was proactive and asked the question before my oral diarrhea of concerns started.

So, they wanted to know about their gait and what to watch out for.  Off the top of your head, without thinking, you should be able to rattle off the following:

  • impaired toe off
  • premature heel rise
  • watchful eye on achilles issues
  • impaired hip extension and gluteal function
  • impaired terminal ankle plantar flexion (because they cannot access the synergists FHL and FHB)
  • impaired terminal ankle dorsi flexion (because they cannot access the synergists EHL and EHB)
  • lateral toe off which will promote ankle and foot inversion, which will challenge the peronei
  • frontal plane hip-pelvis drift because of the lateral toe off and lack of glute function
  • possible low back pain/tightness because of the  frontal plane pelvis drift and from altered hip extension motor patterning (and glute impairment)
  • possible knee pain from tracking challenges because they cannot complete medial tripod loading and thus sufficient pronation to internally spin the limb to get the knee to sagittal loading
  • impaired arm swing, more notable contralaterally

There is more, but that is enough for now. You need to know total body mechanics, movement patterns, normal gait cycle events (you have to know normal to know abnormal) and more. You have to know what normal is to understand when you are looking at abnormal.

* So, dial this back to something more simple, a “stubbed toe”, a painful sesamoid, painful pronation or a turf toe or hallux limitus.  They will all have the same list of complications that need to be evaluated, considered and addressed. This list should convey the importance that if your client has low back pain, examining the big toe motion is critical. Also, if you are just looking at the foot and toe in these cases, pack your bags … .  you don’t belong here. If you are just adjusting feet and toes and playing with orthotics while the list above does not constantly file back and forth through your brain, again, pack all your bags, grab your cat and leave town (just kidding, try reading more and get to some seminars).

If you know the complicated things, then the simple things become … … . . simple.

Your local treadmill gait analysis guru should know all of this if they are going to recommend shoes and exercises. Shame on them if there is no physical exam however. The data roadmap from the gait analysis software print out is not going to get you even out of the driveway let alone down the street. The data is going to tell you what you are doing to compensate, not tell you what is wrong. You must know anatomy, biomechanics, neurology, orthopedics and how to apply them to get the recipe right, not just which shoe in a store will unload the medial tripod of the foot or which exercise will lengthen your stride on the left. 

… .  sorry for the rant, too much coffee this morning, obviously.

Shawn Allen, one of the gait guys

En Pointe, Demi Pointe, Posterior Impingement ?

When we see pictures like this most of us are triggered to look at the toe and the challenges to the 1st MTP joint.  But what about all that compression and crowding in the back of the ankle ? Posterior compression is a reality in athletes who spend time at end range plantarflexion or pack much force and load through end range plantarflexion.

This is a photo example of what is referred to as “en pointe” which means “on the tip”.  “Demi pointe” means on the ball of the foot which is much safer for many areas of the foot, but this requires adequate 1st MTP (metatarsophalangeal joint range). We discussed this briefly this week on social media regarding hallux limitus and rigidus.

En Pointe is a terrible challenge. So if you are thinking of putting your darling children in ballet…… just beware of the facts and do some logical thinking on your own when it comes to allowing the “en pointe” axially loading of the entire body over a single joint, a type of loading that this joint was never, ever, designed to withstand. This joint is a great problem for a great many in their lives, why start playing with the risk factors so early ? Let them dance, into demi pointe, but pull them once they are being forced in to En Pointe, if you want our opinion on the matter.

En pointe or classical point ballet it typically done in point shoes or slippers which have a reinforced toe box that allows a more squared off stable surface to stand in pointe position.  It does not however allow a reduction in the axial loading that you see in this picture and it certainly does not help with proper angulation of the big toe, if anything the slipper will gently corral the toes together rendering abductor hallucis muscle function nearly obsolete.   The box will also not stop the valgus loading that typically occurs at the joint. Despite what the studies say, this is one we would watch carefully.  Now, there are studies out there that do not support hallux valgus and bunion formation in dancers, we admit that.  However, we are just asking you to use common sense.  If you see a bunion forming, if the toe is getting chronically swollen, if the toe is drifting off line then one must use common sense and assume that the load is exceeding joint integrity.  Prolonged and excessive loading of any joint cartilage is likely to create a risky environment to crack, fissure, wear down or damage the cartilage or the bony surface underneath (subchondral bone).  If you screw up this joint, toe off will be impaired and thus the windlass effect at the joint will be impaired thus leading to a multitude of other dysfunctional foot issues in the years to come.

Now, back to the “en pointe” position.  Did you try it yet ? Heed our warning ! Just trust us, this is bloody hard.  Since serious foot deformities can result from starting pointe too early, pre-professional students do not usually begin dancing en pointe until after the age of 10 or so , remember, the adolescent foot has not completed its bone ossification and the bone growth plates have not closed.  Thus, damage and deformity are to be expected if done at too young an age.  If you asked our opinion on this, we would say to wait until at least the mid-teenage years……. but by that point in the dance world a prodigy would miss her or his opportunity.  Thus, we see the problems from going “en pointe” too early in many. In the dance world, there are other qualifications for dancers before En Pointe is begun. Things like holding turnout, combining center combinations, secure and stable releve, 3rd position, 4th position, 4th croise and 5th position all of which are huge torsional demands on the hips to the feet. Do you want your child undergoing these deforming forces during early osseous development ? 

Achieving en pointe is a process.  There is a progression to get to it.  Every teacher has their own methods but it is not a “just get up on your toes” kind of thing.

Are you a dancer with posterior ankle pain, impingement or disability. The Os trigonum and protruding lateral talar process are two common and well-documented morphological variations associated with posterior ankle impingement in ballet dancers. 

Think this stuff through. If you are going to be treating these things, you have to know the anatomy, loading mechanics and you have to know your sport or art. Dr. Allen was a physician for the world famous Joffrey Ballet for a few years, he knows a thing or two about these issues dancer’s endure. And he still has a few nightmares from time to time over them. 

Dr. Shawn Allen


Clin Anat. 2010 Sep;23(6):613-21. doi: 10.1002/ca.20991.Pathoanatomy of posterior ankle impingement in ballet dancers. Russell JA,Kruse DW, Koutedakis Y, McEwan IM, Wyon M

Pain at toe-off; Stopping Big Toe Impingement with the extensor hallucis capsularis.

Photo: note the AET coming off the EHL tendon in the diagram

What if there was a mechanism in place by which to pull structures out of the way of a joint moving to end range ? If you know your biomechanics, you know this is a true phenomenon on several levels. We know of one at the knee, the articularis genu has been written about having function of drawing the suprapatellar bursa and joint capsule/synovial tissue cephalad (upward) during knee extension preventing an impingement phenomenon during full quadriceps contraction in knee extension loading. 

What if there were a similar mechanism in the big toe ? When teaching we are sometimes asked what joint, that when it goes sour, creates more devastation to the entire biomechanical chain than any other joint. I like to choose the big toe/1st metatarsophalangeal joint because failure to fully push off the big toe at full joint range impairs hip extension, stride and step lengths, and creates compensations far and wide ipsilaterally and contralaterally in the body. Most everyone knows about bunions, turf toe, hallux valgus, sesamoiditis and the like, but there are many other things that can make this joint painful. Today we bring you another “clearing mechanism” that acts to pull synovial and capsular tissues out of a joint that is nearing end range.
As seen in the anatomy dissection photo above, the extensor hallucis capsularis (EHC) is an accessory tendon slip off of the extensor hallucis longus (EHL). Interestingly, one study found that 8% of the dissections showed the EHC came off of the tibialis anterior tendon slip. This EHC accessory slip typically originates off the long extensor tendon (EHL) and traverses medially to the dorsomedial joint capsule region. Some studies suggest it is found in 80-98% of people. We propose it is most likely present in everyone because of the critical nature of its function. We propose that perhaps it may be missed on traditional dissections because of its blending with fascial tissues and because of its sometimes trivial size and girth. Just like when we fully extend our knee we want to be sure the articularis genu will draw the synovial capsular tissue up and out of the patellar/femoral approximation, the EHC has been shown on intra-operative testing to exert a pretension on the metatarsophalangeal (MTP) joint capsule similarly pulling the synovial-capsular tissue free from the end range dorsiflexing toe. Without this function, synovial-capsular impingement can occur and create pain and an inhibitory arthrogenic reflex to the EHL, tibialis anterior or any other muscles around the joint for that matter. This can act and feel like an acute “turf toe” (hyper-dorsiflexion event) and yet, not be true turf toe osseous impingement.
So if your client has pain at the dorsal joint on end range extension of the great toe, meaning things like toe-off, doing push ups from the ball of the foot, jumping, kneeling or squatting with the hallux in forced dorsiflexion etc, this tendon slip (and its origin, the EHL muscle) should be on your mind and assessment of the anterior compartment for S.E.S. must commence (S.E.S.= skill, endurance and strength, our Gait Guys mantra). This is why you need to intimately understand this important video (link) and need to know how to do this exercise, the shuffle walks (video link) and build clean ankle rocker ranges of motion via S.E.S. of the anterior compartment.  Pulling on the great toe, twisting it like a radio knob, and forcing end range shouldn’t be the biggest guns in your arsenal, logically restoring all the dysfunctional components should be.

We wonder how many of the videos online of people demonstrating big toe mobilizations, toe distractions, fancy exercises and various toe circus tricks to regain motion and function and reduce pain actually truly know about the anatomy and function of the big toe and how ankle rocker and other things can impair its function.  We wonder about these kinds of things.  

Please just remember, the average uneducated viewer is merely looking for solutions to their painful parts. Those in the know have a responsibility to deliver as complete a package as possible, within reason. 

“With great powers (and knowledge) there must also come, great responsibility.”-Stan Lee  

Dr. Shawn Allen

the gait guys

Photo credit link: http://www.wisconsinfootandankleinstitute.com



Foot Ankle Surg. 2014 Sep;20(3):192-4. doi: 10.1016/j.fas.2014.04.001. Epub 2014 Apr 16.
The extensor hallucis capsularis tendon—a prospective study of its occurrence and function.Bayer T1, Kolodziejski N2, Flueckiger G2.

Foot Ankle Int. 2006 Mar;27(3):181-4.
Extensor hallucis capsularis: frequency and identification on MRI.
Boyd N1, Brock H, Meier A, Miller R, Mlady G, Firoozbakhsh K.

Foot Ankle Int. 2004 Jun;25(6):387-90.
The accessory extensor tendon of the first metatarsophalangeal joint.
Bibbo C1, Arangio G, Patel DV.

The Abductor Heel Twist: Look carefully, it is here in this video.

This should be a simple “piece it together” video case study for you all by this point. This young lad came into our office with left insertional achilles pain of two weeks duration after starting some middle distance running.

What do you see here ? It is evident on both the right and the left, but it is a little more obvious on the left and can be seen on the left when he is walking back toward the camera as well.  You should see rearfoot eversion, it is excessive, and a small rearfoot adductor twist. Meaning, the heel pivots medially towards the midline of his body.  Some sources (Michaud) call this an Abductory Twist, but the reference there is typically the forefoot.  Regardless, to help our patients, we sometimes refer to this is “cigarette butt” foot. It is like stepping on a lit cigarette to put it out via twisting/grinding it into the ground. 

So, now that you can see this, what causes it? 

The answer is broad but in this case he had a loss of ankle dorsiflexion range.  The ankle mortise clearly did not have enough of ankle rocker range during midstance so as that limitation was met, the heel raised up prematurely during the moments when the opposite leg is in full swing imparting an external rotation on the stance limb (hence the external foot spin (adducting heel/abducting foot……depending on your visual reference)). There is a bit more to it than that, but that will suffice for now because it is not the central focus of our lesson today.

What can cause this ? As we said, a broad range of things:

  • hallux limitus
  • flexion contracture of the knee (swelling, pain, joint replacement etc)
  • short calf-achilles complex
  • weak tib anterior and extensor toe muscles
  • Foot Baller’s ankle
  • limited/impaired hip extension
  • weak glute (minimizing hip extension range)
  • sway back (lower crossed syndrome-type biomechanics)
  • short quadriceps (similarly impairing hip extension)
  • flip flop excessive use (or any other motor strategy that imparts more flexor compartment dominance (read: calf-achilles, FDL)
  • excessive pronation
  • impaired foot tripod mechanics
  • etc

The point is that anything impairing TIMELY (the key word is timely) forward sagittal gait mechanics can, and very likely will, impair ankle rocker.  Even the wrong shoe choice can do this (ie. someone who suddenly drops from a 12 mm heel ramped shoe into a 0-4mm ramped heel shoe and who thus may not have earned the length of the calf-achilles complex as of yet).

The abductor-adductor twist phenomenon is not a normal visual gait observation. It is a softly seen, but screaming loud, pathologic gait motor pattern that must be recognized.  But, more importantly, the source of the problem must be found, confirmed and resolved.  In this fella’s case, he has some weakness of the tib anterior and extensor toe muscles that has lead to compensatory tightness of the calf complex. There was no impairment of the glutes or hip extension, as this was just 2 weeks old or so, but if left unaddressed much longer the CNS would have likely begun to dump out of hip extension and gluteal function to protect……another compensation pattern. Remember, ankle rocker and hip extension have a close eye on each other during gait.

Clinical pearl for the true gait geeks…… if you see someone with a vertically bouncy forefoot-type gait (you know, those people that bounce up and down the hallway at work or school) you can usually suspect impaired ankle rocker and if you look closely, you will usually see a quick abductor-adductor twist.

Shawn and Ivo

the gait guys