Retail/Coach/Trainer Focus: When a stability shoe does not stop gait or running pronation.

This video is unlisted. You will need this link to view it if it does not show up in the player above this blog post:    http://youtu.be/Lt6RbEtALUY

This is a higher end stability shoe. We know what shoe it is and you can see the significant amount of dual density mid sole foam in the shoe, represented by the darker grey foam in the medial mid sole.  The point here is not to pick on the shoe or the brand. The point here is to:

1. not prescribe a shoe entirely on the appearance of the foot architecture

2. not to prescribe a shoe merely because a person is a pronator

3. not to assume that a stability shoe will prevent pronation

4. not to assume that technique does not play a part in shoe prescription

5. not to assume that all pronation occurs at the mid foot (which is the traditional thinking by the majority of the population, including shoe store sales people)

There you go, plenty of negatives. But there are positives here. Knowing the answers and responses to the above 5 detractors will make you a better athlete, better coach, better shoe sales person, a safer runner, a more educated doctor or therapist and a  wiser person when it comes to human locomotion. 

A shoe prescription does not always make things better. You have heard it here and we will say it again. What you see is not necessarily what you get.  This case is a classic example of how everything done for the right reasons when so very wrong for this young runner.

What do you see ?

Pronation can occur at:

  1. the rear foot (we refer to this as excessive rear foot eversion or calcaneal eversion driven sometimes by rearfoot valgus). This can be structural (congenital) in the bone (calcaneus or talus) or functional from weaknesses in one or several rear foot eversion controlling muscles.
  2. the mid foot as is traditionally assumed (this is often referred to as “arch collapse” ).
  3. the fore foot. (possibly many causes, such as a Rothbart Foot variant, short first metatarsal, a bunion , forefoot varus, hallux valgus, weakness of the hallux controlling muscles etc)

So, in this case you might assume that the stability shoe that is designed to prevent rear and midfoot pronation is:

  1. not doing its job sufficiently OR
  2. the pronation is occuring at the forefoot OR
  3. there is a myriad of of issues (yes, this is the answer)

However, the keen eye can clearly see that this is a case of heavy forefoot pronation but there are also mechanical flaws in technique (driven by weaknesses, hence just working on her running form will not solve her issues, it will merely force her to adopt a new set of strategies around those weaknesses !). The problems must be resolved before a new technique is forced.  This is perhaps the number one mistake runners make that drives new injuries.  They tend to blame the injury on new shoes, old shoes, increased miles, the fartlek they did the other day, the weather, their mom, there spouse, their kids…….runners come up with some great theories. Heck, all of our athletes do ! It keeps things amusing for us and we get to joke around with our athletes and throw out funny responses like, “I disagree, it was more likely the coming precession of the equinox that caused this injury !”. 

Although his individual does not have a fore foot varus deformity (because we have examined  her) it needs to be ruled out because it is  big driver of what you see in many folks.  In FF varus the forefoot is inverted with respect to the rear foot. This can be rigid (cannot descend the 1st ray and medial side of the tripod) or plastic (has the range of motion, but it hasn’t been developed).

We, as clinicians, like to assume that MOST FEET have a range of motion that folks are not using, which may be due to muscle weakness, ligamentous tightness, pathomechanics, joint fixation, etc. Our 1st job is to examine test the feet and make sure they are competent. Then and only then, after a trial of therapy and exercise, would you consider any type of more permanent “shoe prescription”.

If the individual has a rigid deformity, then you MAY consider a shoe that “brings the ground up” to the foot. Often time we find, with diligent effort on your and the individuals part, that a shoe with motion control features is not needed.

Sometimes the individual is not willing to do their homework and put in the work necessary to make things happen. This would also be a case where an orthotic or shoe can assist in giving the person mechanics that they do not have.

We have not seen many (or any) shoes that correct specifically for a fore foot varus (ie a shoe with fore foot motion control ONLY). The Altra Provision/Provisioness has a full length varus post which may help, but may over correct the mid foot as well. Be careful of what you prescribe.

Yes, we have been studying, blogging, videoing and talking about this stuff for a long time. Yes, much of it is often subtle and takes a trained eye to see. It is also the stuff that goes the “extra mile” and separates good results from great ones.

We are The Gait Guys. Watch for some seminars on some of our analysis and treatment techniques this fall and winter, and some pretty cool video, soon to be released.

Midfoot strike 5 year old running barefoot in grass.

So, heel strike you say ?  Have  a closer look.  This is a near perfect midfoot strike. What you cannot see is his torso progression. As long as the torso has enough forward lean heel strike cannot occur. Heel contact can occur, but not heel strike or impact.

We have talked about this on many occasions here on The Gait Guys Blog. No one else is talking about this fine line difference between heel strike and heel contact.  Everyone still seems hell bent on talking about forefoot strike. Forefoot strike in distance running is not normal, midfoot strike like you see here in this young child is natural and normal. This 5 year old was likely just asked to run barefoot, he was not likely coached. This is because midfoot strike is natural and normal.  As we said, as long as the torso is directly above or in front of the foot contact position there is no way that heel STRIKE can occur, rather heel CONTACT can only occur (unless you have hamstrings like cirque du soleil acrobats and do not mind going into a posterior tilted pelvis at contact). 

We tell our runners to:

  • lift the chest and lean
  • raise the toes and dorsiflex the ankle  (engage the anterior lower leg compartment) so that the arch is maximally prepared
  • a heel KISS of the ground is fine, just no impact
  • you do not need to forefoot strike to run naturally
  • * and, here is one more reason why we like a midfoot strike over a forefoot strike…. because a midfoot strike means that the body continues forward whereas a forefoot strike that then allows into a heel kiss/touchdown means that there is a posterior progression and eccentric lengthening of the posterior chain (hamstrings and calf muscles). This posterior directed motions is not exactly wise when forward progression is the goal of running !

This little fella is doing it right. Largely because he has not been in shoes long enough to corrupt the natural tissues and mechanisms (both the body parts and the natural neuromotor patterns).

* Addendum: after a really productive FAcebook dialogue with some readers we felt we needed to be more clear on some of our unspoken assumptions here.  If the heel hits first, it will be a STRIKE and not a KISS and the load will be high. The only way the heel can kiss the ground like we mention above is if the heel is absolutely contacting at the same time as the forefoot, one could say that there is a more dominant load on the mid-forefoot but the heel can still strike at this same time.  Striking clearly on the forefoot and then touching down the heel is satisfactory but there is still a retrograde movement which we believe is not as economical yet certainly better than heel impact/strike.  To get the perfect midfoot strike with barely a subtle heel CONTACT (not impact or strike) requires greater skill and more mastery as a runner.  And if you are wearing a shoe that is not minimalist or zero drop developing this skill will be a challenge and you will be misleading yourself.    This ammendment added 1 hour post blog post launch.

Shawn and Ivo…….. the Devil is in the Details. 

Cites lack of conclusive evidence By Jordana Bieze Foster http://www.lowerextremityreview.com/issues/may/biomechanist-challenges-idea-that-forefoot-strike-pattern-reduces-runners-injury-rate
“UMass researchers have demonstrated that, although forefoot strikers do not experience a vertical ground reaction force “impact peak,” they do experience impacts during running, albeit at lower frequencies than rearfoot strikers. This research, presented last summer at the American College of Sports Medicine meeting in Denver, suggests that because those lower frequencies are attenuated by muscle tissues, while higher frequencies are attenuated by bone, forefoot strikers may actually face a higher risk of muscle injury than rearfoot strikers. Claims that loading rate is significantly lower in forefoot strikers than rearfoot strikers also may not be entirely accurate, Hamill said. He cited research from Iowa State University, scheduled to be presented in August at the annual meeting of the American Society of Biomechanics, suggesting that when natural forefoot strikers switch to a rearfoot strike pattern, their loading rate actually decreases. Research, most notably the oft-cited Harvard study published in Nature in 2010, have found higher magnitudes of ground reaction force in rearfoot strikers than in forefoot strikers. However, Hamill noted, the heel is a much less delicate structure than the forefoot and therefore may be better suited to absorb higher forces.” 

Biomechanist challenges idea that forefoot strike pattern reduces runners’ injury rate

Retail Focus: The Midsole

The Midsole is the area sandwiched between the out sole and the upper (or vamp, as we have learned).

The two jobs of the midsole are to provide some degree of shock absorption as well as torsional rigidity to a shoe.

Midsole material (usually EVA or similar material) is very important, as it will accommodate to the load imposed on it from the person and their body weight. It serves as the intermediary for load transfer between the ground and the person. 

Softer density material in the heel of the shoe serves to soften the forces acting at heel strike (hopefully NOT when running) and “feels” good for impact and shock absorption. We know from studies we (and you) have read (and posts we have posted) that this is largely perception, as softer midsole materails generally INCREASE impact forces.

The stiffer or denser the midsole material, the more motion control it will provide. This is one of many “motion control features” put into shoes.  Some shoes have two different density foams (called dual density midsoles (see pictures above)), to provide a more graduated resistance. The midsole is softer on its lateral aspect, to absorb force and decrease the velocity of pronation during heel strike and midstance (ie. it keeps you supinated a bit longer), with a firmer material medially that protects against overpronation as you come through mid stance and go through toe off.

Air is an excellent shock absorber, however it does not deform, it displaces. This creates an unstable surface for the foot, promoting ankle injuries. It is great for tires, but we feel does not have a place in shoes. Can you think of any shoes that have Air in the midsole? We can, we have all heard that brilliant marketing campaign.  Foam and gel seem to be much better as they transduce the force and dissipate it.

What’s the bottom line? Materials determine the flex and to some degree, the shock absorbing characteristics of the shoe. More rigid midsoles provide more motion control, less rigid ones less. Not everyone can go into minimalist shoes, and not all need control. But we all need educated.

Want to know more? Take our soon to be released course “Proper Shoe Selection” or better yet, our entire shoe fit course, so you too can be a Shoe Jedi!

Shoe Jedi Masters….The Gait Guys

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Recent trails found in Tanzania suggest fully upright walking began 3.7 million years ago. The footprints they found suggest that the fully upright gait of present day humans existed about 2 million years prior than previously thought ! “The shape of the human foot is probably one of the most obvious differences between us and our nearest living relatives, the great apes. The difference in foot function is thought to be linked to the fact that humans spend all of their time on the ground, but there has been a lot of debate as to when in the fossil record these changes occurred. Our work shows that there is considerably more functional overlap than previously expected,” Bill Sellers, of the University of Manchester’s Faculty of Life Sciences, said in a University of Liverpool news release. Known as the Laetoli trail, the 11 individual footprints found in Tanzania are the earliest known footprints made by human ancestors. The prints reveal features of a gait with more similarities to the way modern humans walk than the bipedal walking of chimpanzees, orangutans and gorillas. The study found that instead of the crouched walking posture with mid foot push off of present day apes, the researchers found that these new found foot impressions categorize a bipedal upright walk driven off the front of the foot and largely the big toe highly representative of the  human gait of today. This study suggested that Australopithecus afarensis had a much different build than that of modern day humans.  Their build had a long torso and short legs.  A reverse of modern man’s physique.  Thus, this studies researchers proposed that this species could only ambulate bipedally for short distances.  _______________________________ Click on the title link at the top  for the link to the copywrited article. Excerpts quoted from the article. So, if you are a believer in evolution (or, have been watching “Ancient Aliens”, the Docu-series on The History Channel   {wry humor}) ……. then this is worthy of longer term memory. Q.  Why is this article here and why do we deem it important to share with you ?  A. Because history is full of clues. To be good in this field of gait and motion, we feel that you should have a decent foundation in anatomy, neurology and physiology, store facts, keep an open mind, study the research (both old and new), do not discount historical information merely because it is old, and consider all options and possibilities so that knowledge can follow from more current experiences). (Fact: such memory items are encoded by your hippocampus, entorhinal cortex, and perirhinal cortex, but consolidated and stored mostly (we think) in your temporal cortex. Tidbit on memory: In gait, Procedural memory refers to movements of the body, such as how exactly to use use a phone, walk or ride a bicycle. This type of memory is encoded and probably stored by the cerebellum and the striatum. have a good week everyone…….. The Gait Aliens……. Shawn and Ivo

Ancient Footprints Reveal Earliest Signs of Human-Like Gait

OK, we are going to go on a rant here…… it is time. We have been talking about problems of forefoot strike for some time now. We like a midfoot strike, and we have research-based, well founded logic to our opinion.  A Forefoot strike reduces the amount of pronation possible for shock absorption because  when the foot is plantarflexed it is in a supinated state which is reserved for a rigid propulsive mechanism.  At impact some degree of pronation is necessary otherwise force attenuation must occur elsewhere in the kinetic chain otherwise it creates bone, joint or soft tissue pathology/injury somewhere in the chain.  However, one of the major issues we have been pounding our fists on the table about, for years, are forefoot orientation anomalies.  A significant portion of the population have forefoot types of varus or valgus, some flexible and some more rigid, some compensated and some uncompenated (yes, this is difficult stuff……but if you are going to make orthotics or if you are going to be a runner or sell or make shoes or coach or even speak about running form styles…… you had better know this stuff or we will call you out on it).  No one is talking about this stuff except The Gait Guys.  Is this because no one knows about it ? Maybe. It is because those in the running fields do not understand it well ? Likely.  It is because it creates fear and anxiety about selling shoes ? Probably. Is it because it complicates shoe fabrication? Likely.  Does that make it right to just ignore it all together ? No !  With a forefoot strike into one of these “pathologic” forefoot types the anatomical variance is accentuated.  In this scenario, a varus foot type that lands and subsequently has not choice but to drive hyperpronation strain not only suffers from the increased pronatory collapse but they are unable to acquire a subsequent rigid toe off which in itself can drive further pathology.  And a valgus forefoot strike is even more rigid than a neutral forefoot strike impact and they are also at risk for inversion strain on the lateral foot.  A midfoot strike can reduce some of these consequences by setting the foot up for a preparatory transition. We know this, we see this everyday, it is what we do. These runners need to be categorized and educated as to why their injury is present or chronically persists, and why we insist a program to reteach a midfoot strike.  As always, if the doctor knows what anatomy presents itself with the client, and adequately educates the athlete……..then a good relationship and outcome will ensue. Additionally, a change in shoe is not  uncommon when their strike mechanics change. Here is what spurred our soapbox rant today…….. thanks Lower Extremity Review for bringing the June ASCM to light early !!! _________________________________________________________________________________ from LER, Link is above: “The frequency content of vertical ground reaction forces generated during running differ among forefoot strikers and rearfoot strikers, and this may have implications for injury risk, according to findings from the University of Massachusetts presented in June at the ACSM meeting. Researchers assessed frequency amplitude and power in 10 natural rearfoot strikers and 10 natural forefoot strikers as they ran across a force platform. At frequencies above 9 Hz, rearfoot strikers’ amplitude exceeded that of forefoot strikers. Similarly, above 22 Hz, power was significantly greater in rearfoot strikers. This is consistent with previous reports that only rearfoot strikers have an impact peak, which occurs between 10 Hz and 20 Hz. But between 4 Hz and 7 Hz, amplitudes were higher in forefoot strikers. And for frequencies less than 6 Hz and between 9 Hz and 11 Hz, power was greater in forefoot strikers. Because the body attenuates shock differently at different frequencies, the findings could suggest that even forefoot strikers (including most barefoot runners) may be at risk for certain injuries despite lacking an impact peak.”

The Risks for Forefoot Strike running. YOU NEED TO READ THIS ! YES, YOU !

Time for a quick pedograph case:

This person presented with arch pain and occasional forefoot pain.

Note the increased size (length) of the heel print with blunting at the anterior most aspect. The midfoot impression is  increased, revealing collapsing medial longitudinal arches. The forefoot print has increased pressures over the 2nd metatarsal heads bilaterally, and the 1st on the left. She claws with toes 2-4 bilaterally.

This demonstrates poor intrinsic stability of the foot (as evidenced by the increased heel impression and midfoot collapse) and well as decreased ankle rocker (as evidenced by the increased forefoot pressures).

We also see increased ink under the distal second digit (esp on the right). This suggests some possible incompetence of the first ray complex and big toe, which is represented by the medial ink presentation under the great toe (suggesting a pinch callus, which is seen when there is spin of the foot and insufficient great toe anchoring and push off).  When the great toe function is compromised, we tend to see increased activity of the 2nd digit long flexors, represented well here by increased ink under the 2nd toe.

The pedograph truly does provide a window to the gait cycle!

We remain: Gait Geeks