Podcast 145: Tendons, Heel Drop and their impacts on the posterior chain,

Heel lifts, Sole lifts and their impact on the EMG of the posterior chain.

Keywords: gait, gait analysis, gait problems, running, ankle, tendinopathy, heel lifts, sole lifts, EMG, paraspinal activity, gluteal inhibition, posterior chain, anterior pelvic tilt, tight quads, diagnostic ultrasound

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Show notes:

Current trends in tendinopathy management
Tanusha B.Cardosoa, TaniaPizzarib, RitaKinsellab, DanielleHopec, Jill L.Cook
https://www.sciencedirect.com/science/article/pii/S1521694219300233

https://www.jospt.org/doi/full/10.2519/jospt.2015.5880

Insightful paper on how tendon adapts to loading and unloading. Discusses a lack of evidence supporting eccentric training as the treatment of choice for injury and notes that tendon response to loading is not normalized until ~6-12 months after injury
https://physoc.onlinelibrary.wiley.com/doi/10.1113/JP275450
The impact of loading, unloading, ageing and injury on the human tendon
S. Peter Magnusson, Michael Kjaer

Effects of heel lifts on lower limb biomechanics and muscle function: A systematic review
Chantel L.Rabusinac, Hylton B.MenzacJodie A.McClellandbcJade M.TanacGlen A.WhittakeracAngela M.EvansaShannon E.Munteanuac
https://www.sciencedirect.com/science/article/pii/S0966636218310075?dgcid=coauthor

The influence of high and low heeled shoes on EMG timing characteristics of the lumbar and hip extensor complex during trunk forward flexion and return task
AnnaMikaa, Brian C.ClarkbcŁukaszOleksy
https://www.sciencedirect.com/science/article/abs/pii/S1356689X13000428

The effect of heel lifts on trunk muscle activation during gait: A study of young healthy females
Christian J.Bartonac, Julia A.CoyleaPaulTinley
https://www.sciencedirect.com/science/article/pii/S1050641108000424

A Systematic Review and Meta-Analysis of Crossover Studies Comparing Physiological, Perceptual and Performance Measures Between Treadmill and Overground Running
https://link.springer.com/article/10.1007/s40279-019-01087-9

Plantarflexor strength and endurance deficits associated with mid-portion Achilles tendinopathy: The role of soleus - ScienceDirect
https://www.sciencedirect.com/science/article/pii/S1466853X18305017

Where the knee hinges matters.

It is easy to see the big things, but, we sometimes forget that the small things matter.
Sometimes it take an obvious glaring asymmetry to make us appreciate that the small asymmetries can make the same or similar impact over a long period of time. Rivers can carve out canyons over time.

Here we see the gross difference that polio can make in leg size and in leg length. We must remember that changing a leg length also changes the symmetrical relationship of where the 2 knees hinge. A foot that pronates more than the other leg can lower the knee hinge point just a little because the talus drops further from its vertical height. We know very well that it for certain alters the hinge direction, posturing it more medially, but we cannot forget that a cranky knee on a side where the foot is flatter or pronates more excessively than the other is not to be ignored.
In this photo, we have dotted the knee at the same point on the patella. It is clear the knees will not hinge at the same time, thus stride and step lengths will change, and step width will be impacted. The pelvis will also spin more to one side on a pelvis that is lower on one side. This will impact lumbar spine sagittal happiness and stability/mobility. Hip and pelvis drift are real things in this case, and need your attention. *Just like a client that has a painful foot, a more pronated foot, more tibial torsion on one side etc. these things matter, and they often matter years down the road when many thousands of miles have been clocked into the subtle asymmetry. Sometimes these little things matter in our athletes too, who put the pedal to the floor asking the body for more.

Come hear our lecture tonight on www.onlineCE.com. You have to sign up early to get in. We won't disappoint. See you then. 7pm central time.

The Circle of Durability.

The article below for some reason inspired today's soft rant. I hope you feel this is worth your time. 
Yesterday I talked about arch height and ankle mortise dorsiflexion and how we can obtain more global dorsiflexion range through some pronation, loosely meaning, some arch compression/drop and splaying apart of the tripod legs of the foot. Global arch flexibility is a piece of that puzzle.  This action of arch compression/drop/tripod splay moves the tibia forward in the sagittal plane and this is global dorsiflexion. Let me be clear however, a reduced ankle mortise dorsiflexion range of sagittal motion which is met by more arch height reduction/prontation/tripod splay, is still dorsiflexion however it is less sagittal dorsiflexion and a little more adduction and medial drift. This can bring the knee into the medial plane and it does promote more internal spin of the limb, this can be a problem.  None the less, it is still global dorsiflexion. It is something we see at the bottom of a squat, we see it because to get there most of us do not have all that dorsiflexion at the mortise. It is not abnormal, the question is, "is it safe for you? Can you do it repeatedly, safely?" It is where we go when we need more sagittal motion, but it may not be ideal, and is often what creates functional pathology. We see it all the time, someone says in an email, "I have plenty of ankle dorsiflexion, that is not my issue".  Do you have plenty? Is it not really your problem? This is fine tuning stuff, it takes a skillful eye and assessment hand. It takes experience to see the whole picture. You cannot get this full 4k experience and understanding from a 2 dimensional youtube video. This arch compression and pronation is normal to occur, it should occur, it must occur. But, how much is too much, for you ? I like to explain it this way, 

"there is a point at which sound, economical, durable, biomechanics becomes a liability. And, at that point where the liabilities begin is in fact where we begin to skirt the edges of that durable skilled movement. Where we begin juggling our liabilities is where the risks begin to mount and begin to whittle away or trump our S.E.S.P (skill, endurance, strength, power). This is where injury often occurs, at that intersection where the gas tank of our S.E.S.P. begins to run low and our liabilities begin to run high." 

Sidebar: 
I have explained this concept many times before when talking about the cross over gait. Moving towards a narrower step width is fine if you have the durability to be there. The question is, how long are you going to be there ? A cross over gait tendency is more economical but you begin to risk liabilities toward injury if that durability becomes challenged. As a runner you must know where your safe zone exists and know how much durability you have at those fringes of your movement. It is when you are there too long, too often, or too much that you empty that durability gas tank which then increases your liabilities towards injury. This is why I give high volume and strength work once a problem is solved, to make sure that they can keep that circle of durability high. It is when we stop keeping our gas tanks large and full that we run on fumes and our risks increase. You might be able to run economically for 5 miles with a narrow step width cross over style running gait. But, can you do it safely at 10 miles ? How about 15?  Is it any wonder why people get injured as they fatigue their safe motor patterns ?  If they have worked hard to keep that circle of durability large (S.E.S.P.) they are bound to be safer and less injured. Injuries occur because we exit our circle of durability, its gas tank has run too low, liabilities now trump economy and durability.

- Dr. Shawn Allen, the gait guys

http://www.japmaonline.org/doi/abs/10.7547/8750-7315-2016.1.Song
 

Gait / Running Injury: Misdiagnosed Big Toe Extensor Hallucis Brevis tear in a distance runner from a simple ankle sprain.

* Sorry for the less than perfect video. Need some editing time.  Watch from 0:32 onwards for the topic at hand.

This young man, State caliber cross country runner, came in to see us after some unsuccessful treatment for an inversion ankle sprain several weeks prior. Although his swelling and range of motion had improved he was still having pain despite treatment.

On examination it was revealed that there was no loss of integrity of the lateral ligamentous restraints, no joint gapping was noted and the ligaments were non-tender. There was no swelling. Balance was clean. Even the immediate local lateral ankle muscular restraints, largely peronei, were competent with skill, endurance and strength assessment.

After further pointed discussion, after the ankle was cleared as a causative /symptomatic generator, we insisted the patient be more specific with his pain region. After requesting he palpate around to focalize the area of complaint this time he pointed not to his lateral ankle but rather pointed to the lateral dorsum of the foot over the fleshy mass of the short extensor muscle group just distal and anterior to the lateral malleolus. Inversion of the ankle was pain free but inversion of the forefoot on the rearfoot reproduced his pain pin point to the EHB (extensor hallucis origin area).

Upon reassessing his gait it was now obvious that he was unable to engage the left hallux (big toe) extensors. You can clearly see his lack of toe extension (lift) on the video at 0:32 seconds. When consciously requested to do so it immediately reproduced his pain ! If you look very carefully, that the hallux was not extending during swing phase through midstance contact phases of gait.

After specific muscle testing found only the EHB (extensor hallucis brevis) weak and not the EDB at all (extensor digitorum brevis) we began a few minutes of manual therapy to the EHB. Within ~5 -10 minutes the EHB was painfree and he could engage the muscle again actively. The muscle was clearly healed from it low grade strain, he was just unable to reactivate it during the gait cycle. Post treatment, he was able to walk immediately with much less pain and with ability to use the EHB in gait.

We followed up a second visit with him but he was pain free and was discharged from care. There were no gait compensations and screens for functional sensory motor compensations were unremarkable. Case closed.

Good results come from a precision diagnosis which can only come from a sound base of knowledge of anatomy, physiology and biomechanics …. when it comes to this kinda stuff.  Would you have picked this up on someone’s gait ? We didn’t at first.  Use your clinical examination to drive your suspicions in your gait analysis. What you see is not always what you get during gait analysis, this easily could have been a similar presentation of a hallux limitus.

Details, details, details. The devil is in the details, The proof is in the pudding……. etc.

Shawn & Ivo