Rearfoot to Hip Pathomechanical considerations.

In normal gait, the rearfoot strikes in slight inversion and then quickly moves through eversion in the frontal plane to help with the midfoot through forefoot pronation phases of gait. Some sources would refer this rearfoot eversion as the rearfoot pronatory phase, after all. pronation can occur at the rear, mid or forefoot. As with all pronation in all areas, when it occurs too fast, too soon or too much, it can be a problem and rearfoot eversion is no different.  If uncontrolled via muscles such as through tibialis posterior eccentric capabilities (Skill, endurance, strength) or from a structural presentation of Rearfoot Valgus pain can arise. 

From a scenario like in the video above, where a more rearfoot varus presentation is observed,  where the lateral to medial pronation progression is excessive and extreme in terms of speed, duration and magnitude this can also create too much lateral to medial foot, ankle and knee movement.  This will often accompany unchecked movements of internal spin through the hip. So one should see that these pronation and spin issues can occur and be controlled from the bottom or from the top, and hopefully adequately from both in a normal scenario.  It is when there is a biomechanical limitation or insufficiency somewhere in the chain that problems can arise. And remember, pain does not have to occur where the failure occurs, in fact it usually does not. So when you have knee pain from an apparent valgus posturing knee, make sure you look above and below that knee.  Also, keep in mind that as discussed last week in the blog post on ischiofemoral impingment syndrome (link), these spin scenarios can be quite frequently found with ipsilateral frontal plane lateral deviations (bumping of the hip-pelvis outside the vertical stacking of the foot-knee-hip stacking line). This stacking failure can also be the source of many of the issues discussed above, so be sure you are looking locally and globally. And remember, what you see is not the problem, it is their compensation around their deeper problem quite often.

If you have not read the blog post from last week on ischiofemoral impingement syndrome you might not know where the components of the cross over gait come in to play here nor how a rearfoot problem can present with a hip impingement scenario, so I can recommend that article one more time.

One last thing, just in case you think this stuff is easy to work through, remember that these rearfoot varus and valgus problems, and pronation rates. and limb spin rates are all highly variable when someone has varying degrees of femoral torsion, tibial torsion or talar torsion. Each case is different, and each will be unique in their presentation and in the uniqueness of the treatment recipe. I just thought I would throw that in to make your head spin a little in case it wasn’t already.

For example, a case where the rearfoot is a semi rigid varus, with tibial varum, and frontal plane lateral pelvic drift with components of cross over gait (ie. the video case above) will require a different treatment plan and strategy than the same rearfoot varus in a presentation of femoral torsion challenges and genu valgum. Same body parts, different orientations, different mechanics, different treatment recipe.  

So, you can fiddle with a dozen pair of shoes to find one that helps minimize your pains, you can go for massages and hope for the best, you can go and get activated over and over, you can try yet another new orthotic, you can go to a running clinic and try some form changes, throw in some yoga or pilates, compression wear, voodoo bands and gosh who knows what else. Sometimes they are the answer or stumble across it … or you can find someone who understands the pieces of the puzzle and how to piece a reasonable recipe together to bake the cake just right. We do not always get there, but we try.  

Want more ? Try our National Shoe Fit certification program for a starter or try our online teleseminars at www.onlinece.com (we did a one hour course on the RearFoot just the other night, and it was recorded over at onlineCE.com).

Dr. Shawn Allen,  of the gait guys

Reference:

Man Ther.  2014 Oct;19(5):379-85. doi: 10.1016/j.math.2013.10.003. Epub 2013 Oct 29.Clinical measures of hip and foot-ankle mechanics as predictors of rearfoot motion and posture.  Souza TR et al.

Health professionals are frequently interested in predicting rearfoot pronation during weight-bearing activities. Previous inconsistent results regarding the ability of clinical measures to predict rearfoot kinematics may have been influenced by the neglect of possible combined effects of alignment and mobility at the foot-ankle complex and by the disregard of possible influences of hip mobility on foot kinematics. The present study tested whether using a measure that combines frontal-plane bone alignment and mobility at the foot-ankle complex and a measure of hip internal rotation mobility predicts rearfoot kinematics, in walking and upright stance. Twenty-three healthy subjects underwent assessment of forefoot-shank angle (which combines varus bone alignments at the foot-ankle complex with inversion mobility at the midfoot joints), with a goniometer, and hip internal rotation mobility, with an inclinometer. Frontal-plane kinematics of the rearfoot was assessed with a three-dimensional system, during treadmill walking and upright stance. Multivariate linear regressions tested the predictive strength of these measures to inform about rearfoot kinematics. The measures significantly predicted (p ≤ 0.041) mean eversion-inversion position, during walking (r(2) = 0.40) and standing (r(2) = 0.31), and eversion peak in walking (r(2) = 0.27). Greater values of varus alignment at the foot-ankle complex combined with inversion mobility at the midfoot joints and greater hip internal rotation mobility are related to greater weight-bearing rearfoot eversion. Each measure (forefoot-shank angle and hip internal rotation mobility) alone and their combination partially predicted rearfoot kinematics. These measures may help detecting foot-ankle and hip mechanical variables possibly involved in an observed rearfoot motion or posture.

Podcast 70: Achilles Solutions and Foot Cases

The Achilles and Calf: Achieve Posterior Length via Anterior Strength

A. Link to our server: 

Direct Download: 

http://traffic.libsyn.com/thegaitguys/pod_70final_was71.mp3

Permalink: http://thegaitguys.libsyn.com/podcast-70-0B. 

iTunes link:

https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138

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

http://store.payloadz.com/results/results.aspx?m=80204

D. other web based Gait Guys lectures:

www.onlinece.com   type in Dr. Waerlop or Dr. Allen,  ”Biomechanics”

______________

Today’s Show notes:

*Show sponsor: Lems Shoes.  www.lemsshoes.com
Mention GAIT15 at check out for a 15% discount through August 31st.
 
1. Achilles tendons, loading, and biomechanical changes with different shoes and heel stack heights.
 
2. Aging adults, falls and keeping them and their gait safe.
 
3. Gait and speed evolution of vertebrates.
 
4. Blaise Dubois et al on Barefoot Running. Shod vs unshod.
 
5. Females, pronation, and back pain. The Framingham foot study.
 
6. Your feet and orienteering.
 
7. A case of calcaneal valgus in a youngster.
 
8. Structural integrity is decreased in both Achilles tendons in people with unilateral Achilles tendinopathy

http://www.jsams.org/article/S1440-2440(14)00115-7/abstract

The Case of the Non Rotating Knee

Here is a runner, wanting to be an ultra runner, who recently developed right sided knee pain while running a 50K. He was pacing another individual and developed pain on the outside (lateral patella and knee) on the right, ascending and especially descending hills. The pain is dull and achy. He is able to “push through” the pain, but if he does, it remains painful for a few days.

He has an anatomically short leg on the L (tibial). There is no significant tibial torsion (he has normal external version) and not femoral torsion. There are adequate amounts of internal (>15 degrees) and external (>30 degrees) rotation of the hips.

He has 7 degrees ankle dorsiflexion on the right, 10 degrees on the left. On the table (and in the video) he has 0 degrees of hip extension during passive motion, walking and running. He has weakness of the long extensors of the toes, as well as the abductors.

Take a look at his video. Note the following:

·       the right knee has less medial excursion than the left (watch the dots)

·       rearfoot valgus is noted on the L  (ie. calcaneus is everted)

·       subtle lean to Left on L sided stance phase

·       when barefoot, the problem lessens

Why does the right knee rotate less than the left?

When folks have a short leg, we generally expect that leg to remain in supination (thus external rotation) more and the longer leg to internally rotate more, due to excessive pronation. But here, we see the opposite. You will notice he has a rearfoot valgus on the left. This means the midtarsal joint is in a greater amount of pronation on the shorter side. For every action, there is an equal and opposite reaction. In this case, less pronation (or supination) on the longer leg side. Remember, we said generally folks pronate more on the long leg side. This is one of the exceptions.

So, should he throw away his shoes?

The shoes, which have a certain amount of torsional rigidity, are compounding the problem. The Brooks Cascadia is an excellent trail running shoe, he just needs something with less torsional rigidity. the shoe does  not allow his knee to come midline sufficiently. Since he is a Brooks Fan, we suggested the “Grit” in the Pure line. 4mm drop and less rigid torsionally. He could also work his way into a “Drift” (4mm or zero drop, extremely flexible).

Why does he lean to the left on stance phase on the left?

Most likely, to clear the right long leg on swing phase. This is one of the 5 common strategies. For more strategies, click here.

Why is it better when he is barefoot? It must mean he should be a barefoot runner, right?

He is better, because there is less impediment to the foot pronating (ie. the shoe has less torsional rigidity)

The Gait Guys. Making you a better diagnostician, with each and every post.

The Great Myth of Rotating your Shoes : Here are the Actual Facts as we see them.

Everyone has heard the rules, rotate into new shoes about every 400-500 miles.  We disagree, kind of, and we have talked about it on previous blog posts in the past and on our podcasts.  Many shoe reps have agreed with the methods we employ for our runners.

The EVA foam often used in shoe manufacturing has a lifespan, or better put, a given number of compression and shear cycles. It can go through a rather fixed number of compression cycles before it loses its original structural properties, the older the foam gets the faster the degradation process and the more risks it poses for runners.  It is known that EVA foam compressed into a focal vector or area over and over again becomes softer and more giving into that vector/area over time.  Hence, if you have a compensation pattern or a known foot type (forefoot varus, forefoot valgus, rearfoot varus, rearfoot valgus or a combination of these 4) you will break down a certain region or zone of the shoe’s EVA foam. For example a forefoot varus foot type will often drive some heavy focal compression into the foam under the first metatarsal. However, if you combine it with a rear foot valgus it will drive shear forces and compression into the  EVA foam along the entire medial aspect of the shoe (see the 2 pictures attached, you can see the evidence of excessive medial compression and medial shear in a foot that has severe rearfoot valgus and forefoot varus. This is a very poor shoe prescription for the foot type involved).

Here is what you need to do / know:

1- Know your athletes foot type so you can make more informed decisions.

2- Know the type of foam of the shoes you are recommending (ie. Altra uses A-Bound foam instead of EVA just as an example. A-Bound is an environmentally friendly energy-return compound is made of recycled materials. It reduces the impact of hard surfaces while still maintaining ground feedback. Traditional running shoe foam compresses 70-90% while A-Bound™ compresses 2-3x less so it won’t deform over time.).  Cheap shoes use cheap materials.  Altra goes the extra mile for foam quality and many others are beginning to follow suit. If you think you are getting a deal on shoes, know what “the deal” is, it just may be cheaper materials.

3-  500 miles is not the rule for everyone and every shoe.  If you have a relatively neutral forefoot and you are a forefoot or midfoot strike runner you will get far more miles out of a shoe.  If you depend on a stability shoe with dual densities of foam to slow your pronation and control your medial foot because of a rearfoot valgus and/or forefoot varus know that the shoe’s foam will break down less uniformly because of foam interface junctions and whatnot.  This is a science. Engineers call it “the mechanics of material deformation”.  We wonder how many mechanical engineers shoe companies have on board in their R&D divisions ?  We know for a fact that a few do not. There was a reason we snuck quietly into the mechanical engineering departments of our Alma Mater and sat quietly in the “Materials” classes. At the time our roommates just told us it was  cool class, little did we know why it was so interesting to us, until now.

4- Here is what we recommend. Fit the foot type to the right shoe selection. If you are weak in this territory consider taking our intense “National Shoe Fit” program. Fit is everything. Make the wrong choice for your client and the shoes will break down quicker and into poor and risky patterns. Make the right choice and be their hero. If you are looking for a way to improve clientele happiness and store loyalty our Shoe Fit Program is the way. Just read the testimonials here on our blog. Some of the top stores in the Nation have quietly taken the National Shoe Fit Program from us, they have good reason to. They also have good reason to keep it quiet, to get the edge on the competition.

You can email us to get this information and the e-file program download. Why not certify your entire store staff ?

Email us at   thegaitguys@gmail.com.  This program will teach you foot anatomy, functional anatomy, shoe anatomy, foot types and matching foot type to shoe type as well as many other aspects of gait and lower limb biomechanics.

* 5- Try this recommendation.  At 250 miles buy a new shoe to accompany your shoe that already has 250 miles. Now you are rotating 2 shoes. From this 250 mile point moving forward, alternate the newer show with the older shoe. This way you are never in a shoe that is notably more deformed in a specific area of the EVA foam because of your compensations, limitations or foot type. Essentially you are always just a day away from a newer shoe that has less driving force into abnormally compressed EVA foam.  The older the shoe gets the more it accelerates your foot and body into that deformation and hence why many injuries occur as their shoes get older. Continue to alternate shoes on every other run (new, old, new, old).  Once you hit 400-500 miles on the old shoes, ditch them and get a new pair again to restore the cycle once again.  In fact, to be specific here is what we recommend. Monday, old shoe. Tuesday, new shoe. Wednesday do not run, rather, rest or cross train. Thursday go back to the older shoe. Friday new shoe and repeat. This way you are 4 days between runs in the older more deformed shoe. The one day off running in mid week gives tissues that were challenged by the “old shoe run” a bit more time to repair.

6- Dedicate your shoes to running only. Running gait is not the same as walking gait. Why would you want to break down the EVA foam at the rear foot during walking (because heel strike is normal in walking) when in running you are a mid-forefoot striker ?  Keep walking shoes for walking, running shoes for running. Otherwise you are just asking for trouble.

Check out our National Shoe Fit program and certification process here as well as links to our other teaching DVD’s & e-downloads:
 http://store.payloadz.com/results/results.asp?m=80204

Shawn and Ivo. Helping you use your head (and shoe knowledge) better everyday.
The Gait Guys  (have you checked out our RebelMouse page ? https://www.rebelmouse.com/TheGaitGuys/

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