Too much pressure for the holidays? Take a look at that midsole of yours…

In the vein of last weeks post on plantar pressures, we find that midsoles DO DECREASE plantar pressures, especially across the midfoot (30% less pressure in this study), again dependent on foot type (In this study, low vs high arched individuals). They also INCREASE plantar contact area. Contact area can be useful for helping to influence biomechanics of different foot types (often more contact area = more force attenuation)

We also saw that they increase pressures LATERALLY (see our post here).

Bottom line? You need to look at foot type and remember that “shoes are medicine”. Watch what you are prescribing and think about what you are trying to accomplish. There is no substitute for good biomechanics.

We are The Gait Guys. Bringing you the best of gait, each week.

Shoe Types and plantar pressures

J Am Podiatr Med Assoc. 2009 Jul-Aug;99(4):330-8. Effect of running shoe type on the distribution and magnitude of plantar pressures in individuals with low- or high-arched feet. Molloy JM, Christie DS, Teyhen DS, Yeykal NS, Tragord BS, Neal MS, Nelson ES, McPoil T. Source US Army-Baylor University Doctoral Program in Physical Therapy, Ft Sam Houston, TX 78234-6138, USA. Joseph.Molloy@amedd.army.mil

Abstract BACKGROUND:

Research addressing the effect of running shoe type on the low- or high-arched foot during gait is limited. We sought 1) to analyze mean plantar pressure and mean contact area differences between low- and high-arched feet across three test conditions, 2) to determine which regions of the foot (rearfoot, midfoot, and forefoot) contributed to potential differences in mean plantar pressure and mean contact area, and 3) to determine the association between the static arch height index and the dynamic modified arch index.

METHODS:

Plantar pressure distributions for 75 participants (40 low arched and 35 high arched) were analyzed across three conditions (nonshod, motion control running shoes, and cushioning running shoes) during treadmill walking.

RESULTS:

In the motion control and cushioning shoe conditions, mean plantar contact area increased in the midfoot (28% for low arched and 68% for high arched), whereas mean plantar pressure decreased by approximately 30% relative to the nonshod condition. There was moderate to good negative correlation between the arch height index and the modified arch index.

CONCLUSIONS:

Cushioning and motion control running shoes tend to increase midfoot mean plantar contact area while decreasing mean plantar pressure across the low- or high-arched foot.

all material copyright 2012  The Gait Guys/ The Homunculus Group. Please ask before using our stuff or Santa will bring you athletes foot this holiday season. 

Since the world did not end, you should probably think twice about those motion control shoes….

WE can all agree that there is a time and a place for motion control shoes. For people with chronic ankle sprains or lateral instability (ie, an incompetent lateral compartment; peroneus longus, brevis or tertius), it is neither the time, nor the place.

The lateral ankle is stabilized by both static (ligaments: above lower left) and dynamic (muscles above, lower right) elements. This is often called “the lateral stabilizing complex” The lateral ankle (ie the lateral malleolus) also projects more inferiorly than the medial. This means that when push comes to shove, the ankle is more likely to invert (or go medially) than evert (or go laterally). What protects it? The static component consist of three main ligaments (seen above) the posterior and anterior talofibular ligaments and the calcaneofibular ligaments. The dynamic components are the peroneii muscles. These muscles not only stabilize but also exert an eversion (brings the bottom of the foot to the outside) force on the ankle.

So what you say?

according to one study we found “Using an in-shoe plantar pressure system, chronic ankle instability subjects had greater plantar pressures and forces in the lateral foot compared to controls during jogging.”

Hmmm. Remember the midsole? (If not click here and here for a review) Motion control shoes are medially posted. That means they provide more support medially or  have a tendency to tip the foot laterally. SO, motion control shoes shift forces laterally.

A person with chronic ankle instability has weakness of either the static, dynamic, or both components of the lateral stabilizing complex.

bottom line? make sure folks have a competent lateral stabilizing complex and if they don’t, you may want to think twice about using a motion control shoe.

Ivo and Shawn. Increasing your shoe geekiness coefficient on daily basis!                                                                                                                                                    

Foot Ankle Int. 2011 Nov;32(11):1075-80. Increased in-shoe lateral plantar pressures with chronic ankle instability. Schmidt H, Sauer LD, Lee SY, Saliba S, Hertel J. Source University of Virginia, 2270 Ivy Road, Box 800232, Charlottesville, VA 22903, USA.

Abstract BACKGROUND:

Previous plantar pressure research found increased loads and slower loading response on the lateral aspect of the foot during gait with chronic ankle instability compared to healthy controls. The studies had subjects walking barefoot over a pressure mat and results have not been confirmed with an in-shoe plantar pressure system. Our purpose was to report in-shoe plantar pressure measures for chronic ankle instability subjects compared to healthy controls.

METHODS:

Forty-nine subjects volunteered (25 healthy controls, 24 chronic ankle instability) for this case-control study. Subjects jogged continuously on a treadmill at 2.68 m/s (6.0 mph) while three trials of ten consecutive steps were recorded. Peak pressure, time-to-peak pressure, pressure-time integral, maximum force, time-to-maximum force, and force-time integral were assessed in nine regions of the foot with the Pedar-x in-shoe plantar pressure system (Novel, Munich, Germany).

RESULTS:

Chronic ankle instability subjects demonstrated a slower loading response in the lateral rearfoot indicated by a longer time-to-peak pressure (16.5% +/- 10.1, p = 0.001) and time-to-maximum force (16.8% +/- 11.3, p = 0.001) compared to controls (6.5% +/- 3.7 and 6.6% +/- 5.5, respectively). In the lateral midfoot, ankle instability subjects demonstrated significantly greater maximum force (318.8 N +/- 174.5, p = 0.008) and peak pressure (211.4 kPa +/- 57.7, p = 0.008) compared to controls (191.6 N +/- 74.5 and 161.3 kPa +/- 54.7). Additionally, ankle instability subjects demonstrated significantly higher force-time integral (44.1 N/s +/- 27.3, p = 0.005) and pressure-time integral (35.0 kPa/s +/- 12.0, p = 0.005) compared to controls (23.3 N/s +/- 10.9 and 24.5 kPa/s +/- 9.5). In the lateral forefoot, ankle instability subjects demonstrated significantly greater maximum force (239.9N +/- 81.2, p = 0.004), force-time integral (37.0 N/s +/- 14.9, p = 0.003), and time-to-peak pressure (51.1% +/- 10.9, p = 0.007) compared to controls (170.6 N +/- 49.3, 24.3 N/s +/- 7.2 and 43.8% +/- 4.3).

CONCLUSION:

Using an in-shoe plantar pressure system, chronic ankle instability subjects had greater plantar pressures and forces in the lateral foot compared to controls during jogging.

CLINICAL RELEVANCE:

These findings may have implications in the etiology and treatment of chronic ankle instability.

 

all material copyright 2012 The Homunculus Group/ The Gait Guys. Don’t rip off our stuff. PLEASE ASK 1st!

Excessive Supination in a marathoner: Shoe Photos !

Simple visual case today.

Look at the right shoe, can you see how it is canted laterally? Can you see the inversion of the rear foot ?  Without a foot in that shoe it means that “the last”, the heel counter and the EVA foam are all destroyed and deformed into this great runner’s compensation pattern. 

They did not have pain however can you determine the problem here from the photos ? We hope your answer is no.  We did a teleseminar last night on www.onlineCE.com on pedograph foot mappings and we talked long and hard about the possible limitations of determining foot problems from foot pressure mappings from things like pedographs and pedobarographs.  Do you use foot scanners ? If so, user beware !  They gather vital and valuable information that you absolutely need but you need the critical clinical information from the client examination to bring the foot issue info full circle.

In this case there was a significant limitation in hip rotation. Which one ? Can you theorize ?  If you said internal rotation you are right. There was a notable loss of internal right hip rotation in his marathoner.  And it is represented in his shoe photo above. Someone who has a loss of internal hip rotation will often (but not always) have difficulties achieving the normal foot pronation required for clean foot mechanics, they will be stuck in a supination tendancy.  If loss of internal rotation can mean loss of pronation then in this case ample external rotation meant excessive supination (or at the very least rear foot inversion). Hence the shoe presentation described at the beginning of this post. (Note: this is what we would refer to as a “Flexible” Rear foot Varus posturing).

So, is this the wrong shoe prescription for this runner ? No, the shoes were prescribed correctly. This is a biomechanical breakdown of a shoe because of a hip functional problem.

Solution: Dump the shoes for a new pair and quickly restore hip function. Keeping these shoes in the mix will promote the bad pattern.  In this case, functional movement and muscle tested assessments revealed specific weakness of the right lower transverse abdominus, right internal abdominal oblique, right TFL, right vastus lateralis and coccygeal division of the g. max.   Yes, all INTERNAL HIP ROTATORS  or stabilizers or synergists of internal hip rotation.  Immediate post treatment remedy revealed near full internal hip rotation and homework was prescribed to ramp those said muscles up further to support the new movement. 

If he had remained in this shoe, the breakdown in the shoe would continue to promote the biomechanical deviations into the previously engrained faulty motor compensatory pattern. 

Shoes, sometimes they are the problem, sometimes the solution and sometimes caught somewhere in between.

Need to get better at this stuff ? Just follow us daily here on The Gait Guys or consider adding the National Shoe Fit Program to your repertoire !  Email us if you are interested or need some help with your interesting cases !

Shawn and Ivo, The Gait Guys

Shoe News You can Use…

The Heel Counter– the back of the upper

This is the back of the shoe that offers structure (just squeeze the back of a shoe. this is the rigid part you feel between your thumb and 1st finger, unless of course, you are using your teeth). This is often part of or integrated with the upper.

A strong, deep heel counter with medial and lateral support is important for motion control; It offers something for the calcaneus (heel bone) to bump up against when as it is everting (moving laterally) during pronation. Look at folks that have a bump on the outside of their heel (particularly the ladies(sorry, true); this is often called a “pump bump”). Now look at the inside of their shoes. See that worn away area on the inside of the back of the shoe? Now you know where that worn away area is coming from!

Lateral support especially for people who invert a great deal or when you’re going to place an orthotic in the shoe which inverts the foot a great deal.  The lateral counter provides the foot (or orthotic) something to give resistance against.  The lateral counter needs to extend at least to the base of the fifth metatarsal, otherwise it can affect the foot during propulsion. A deep heel pocket in the shoe helps to limit the motion of the calcaneus and will also allow space for an orthotic. The heel counter should also grip right above the calcaneus, hugging the Achilles tendon.

We know you want to know more. We can help. Take the National Shoe Fit Certification Program. If you like, sit for the exam and get certified as well. Email us for details thegaitguys@gmail.com

The Gait Guys. We’re your heel counter!


all material copyright 2012 The Homunculus Group/ The Gait Guys. All rights reserved. If you want to use our stuff, please ask. If not, Captain Cunieform may pay you a visit…

Are old running shoes detrimental to your feet? Here is some research.

Are old running shoes detrimental to your feet? A pedobarographic study.

by: Rethnam U, Makwana N.

STUDY BACKGROUND: “Footwear characteristics have been implicated in fatigue and foot pain. The recommended time for changing running shoes is every 500 miles. The aim of our study was to assess and compare plantar peak pressures and pressure time integrals in new and old running shoes.”

CONCLUSION:

“Plantar pressure measurements in general were higher in NEW running shoes. This could be due to the lack of flexibility in new running shoes. The risk of injury to the foot and ankle would appear to be higher if running shoes are changed frequently. We recommend breaking into new running shoes slowly using them for mild physical activity.”

What do The Gait Guys say ? Did you read our post yesterday on this very topic ? Here is the link.  Never let a pair of shoes get too old before breaking in a new pair. The old shoes can be just as much of a problem as the new shoes.  Old shoes break down the foam into possible detrimental biomechanical patterns that can promote overstress to areas and create injury. A new shoe can be stiffer and thus change your biomechanics away from what is clean function for you.

So what is the solution ? If you read our blog post yesterday you know the answer (see #5 in yesterday’s blog post). LINK  (Blog post December 5th, 2012).

Shawn and Ivo, The Gait Guys

BMC Res Notes. 2011 Aug 24;4:307.

Are old running shoes detrimental to your feet? A pedobarographic study.

Source

Department of Orthopaedics, Glan Clwyd Hospital, Rhyl, UK. ulfinr@yahoo.com.

http://www.ncbi.nlm.nih.gov/pubmed/21864342

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/

Keeping up with our awesome informative podcasts ? It is all free stuff ! https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138

How about our youtube channel ? http://www.youtube.com/user/thegaitguys

How about our Facebook PAGE ?  https://www.facebook.com/pages/The-Gait-Guys/169366033103080

More to say about the National Shoe Fit Certification Program…
“I found the course to be the perfect blend between science and retail practices, making it an essential tool for any specialty running store. Immediately after finishing the video I was able to recognize specific issues in my customer’s feet and their reaction to my knowledge couldn’t have been more positive. As a result of becoming certified I will have happier and healthier customers and will know when to refer particular foot and gait issues to my partner doctors and physical therapists. The video will be a resource long after becoming certified.”

Ben Nelson is the manager of Goldstream Running, the farthest north run specialty shop in North America (and maybe the world!), located in the Goldstream Valley outside of Fairbanks, Alaska. He also coaches high school cross country and track and field.

Want to know more about getting certified? drop us an email: thegaitguys@gmail.com