More on the “Earth” shoe

3.7 degrees. Who (besides maybe Kevin Bacon) would have thought a few degrees could make that much of a difference?

We don not doubt that the shoe helps you to burn more energy. You are walking up hill against your normal biomechanics. Inefficiency usually costs more energy.

Remember our friend “PRONATION”? It consists of dorsiflexion, eversion and abduction. SOME PRONATION is requisite for normal gait. It is one of the 4 shock absorbing mechanisms, along with ankle dorsiflexion, knee and hip flexion. (Midfoot) PRONATION begins from initial contact of the heel with the ground (loading response); friction of the heel on the ground causes the talus to slide anteriorly on the calcaneus and it then plantar flexes, adducts and everts to lower the midfoot. This goes on until MIDSTANCE, when the opposite leg begins to go into swing phase which initiates SUPINATION.

We remember PRONATION makes the foot into a “mobile adaptor” for shock absorbtion; SUPINATION makes the foot into a rigid lever for propulsion. The question is: “Why keep the foot in a position that would decrease biomechanical efficiency for ½ of the gait  cycle?”

We do not refute that the shoe does burn more energy. We agree that it will reduce the lordosis of the low back, which can be beneficial for spinal canal stenosis and a few other conditions which demand less stress on the facet joints. We like the wide (though not anatomic) toe box.

Negative ramp delta? We are not convinced this is great idea.

Ivo and Shawn. Triangular, pointy (but beautifuul and bald) heads (like a delta). Bringing you the facts so you can make better decisions.

In our series of questions we get…

Dear Gait Guys
I was reading an article the other day about the foot and intrisic muscles to gain more insight into the function and how to re-train these muscles. I am having a difficult time trying to g…
In our series of questions we get…

Dear Gait Guys

I was reading an article the other day about the foot and intrisic muscles to gain more insight into the function and how to re-train these muscles. I am having a difficult time trying to give patients exercises for intrisic muscles when everyone seems to say something different. The most recent I have read is that the best way to retrain the lumbricals is stand on your toes and walk up steps. I can see some logic in this but also seems a very generic exercise and would encompass alot more flexor driven muscles that are likely already strong. I was wondering if you have a more specific exercise that would be simple and easy for patients to do?

Dear Lumbricals

We would have to agree with you that the exercise is very generic and would cause overuse of the flexors, though it would stimulate lumbrical function.

As you are aware, the lumbricals attach proximally to the sides of adjacent tendons of the flexor digitorum longus (with the exception of the 1st, which only attaches to the medial side) and attach distally to the medial aspect of the head of the proximal phalynx and continue on to the extensor hoods in toes 2-5 .

Their typical function is described as flexion of the proximal phalynx and extension of the proximal and distal interphalangeal joints. They have the unique ability to compress the metatarsal-phalangeal and inerpahlangeal joints. There is also a small adductory moment to counteract abductory shear, due to the tendon passing medial to the metatarsal-phalangeal joints (michaud). These are open chain functions. Unless you are in the habit of waving to people with your toes, they often are used quite differently. But this brings upa good point and excellent exercise we call “waving the toes”.

They are performed by holding the great toe in dorsiflexion (hopefully, without assistance) and flexing the other toes at the MTP joint, while keeping the PIP and DIP in extension. This requires and intact and functional EDL (with good motor control!)

Another exercise is sitting with the foot relaxed and concentrating on flexing the toes (2-5) without clawing (similar to above, without the Hallux extended.

Remember they work from mid to terminal stance, but you need to develop skill before endurance or strength.

We hope this helps, 

The Gait Guys

As a runner: To Cross-Over or not to Cross-Over ?   That is the question. Lets go back and talk about the Cross Over Gait again (yes, again). This is the next level.

*watch this video (link) and notice 2 things: 1. the size of the glutes on these amazing athletes and 2. pay attention to the few seconds at 1:32. No Cross Over gait anywhere.

If you look at any video on the web of ANY sprinter in competition from the front or back (sagittal progression), you will always see the knees and feet falling underneath the hips. Watch video above again and see this. You will never see a sprinter cross over like we see in many distance runners.  Why is that ? Here, look this video (link)  as well, at the 1:30 mark there is a great overhead view of the field, look for one of these fellas crossing over, you will not see it.  Here are starts out of the blocks, clear abduction (link) and no cross over, in fact there is more leg abduction separation coming out of a start to get more glute power (think of a skater, same thing).  Now get on YouTube and watch any distance race and you will have to work at finding non-Cross Over runner or at least someone who is at the tipping point. Everyone does it, but does that make it right ? Does it make it wrong ? Does it make them vulnerable to injury more ?  We think it does.

We believe to reduce injury the cross over needs to be corrected. However, in distance running less brute power is needed, we need to conserve energy so we need to dial to a more reasonable and economical and efficient running gear.  In distance athletes and your typical 20+ mile a week runner less gluteal power is needed, but most runners have just gone past that tipping point and get into under use and begin to cross over.  Lets see if we can expand on this theory a little more.

Well, there are no studies on this. As far as we know we are the only ones trying to solve this mystery of the tipping point cross over gait/run style. Go ahead, search on the web, we seem to be on a solitary voyage all on our own, thankfully we have our Gait Guys brethren (you guys !) with us.  It does however bode the question for us,  “Why are we able to get so many of these chronic distance runners over their injuries by addressing their Cross-Over Gait and its frequent weaknesses (gluteus medius/maximus/medial quadriceps), excessive pronation and their tightness’s (IT band etc). Why do our sprinters have an entirely different injury pattern  ?”  Sure the athletes are different and their events are different, that is the simple answer but it is not good enough.  One athlete is built for speed, the other built for distance and endurance. But there is something big here that needs all of our attention.

Here is the fundamental difference.  We get some vocal challenges particularly from distance runners (but less with time as our theory has yet been refuted) that the cross over is more efficient for a distance runner.  (Example of another great cross over here in case you are new to our work on this topic (video link)). We disagree, for now, until research can disprove our theory which has been several years in development.  The Cross Over Running form challenges the normal pendulum effect of the lower limbs and challenges the biomechanics of the hip frontal plane stabilizers, namely the gluteus medius (need a biomechanics refresher? , click here).  Why would you want to change the natural leg pendulum in a runner ? This is not good running economy, although you will have a fight on your hands if you ask a runner to convert to our anti-cross over gait and drag them from their deeply engrained and comfortable cross over running style ! Beware, they are going to tell you it doesn’t feel right, it is too hard, it feels awkward, “it cannot be right !"  Well, so does brushing your teeth with the opposite hand but that doesn’t make it wrong.  Our 3 part series on Cross Over Running is pretty thorough if you want to learn more, but this is not the place. We feel we have been pounding the floor on those issues long enough.

Here is our question, go and do your own observational work as well. 

Look at the glutes of sprinters (watch the main video with this post again), compare size ratio of glutes to quads. Sprinters have bigger glutes, sure they have massive legs but they have glutes to match that power.  Their glutes are in charge of their hip and pelvic mechanics. When there is mismatch there is often injury.

Distance runners have much smaller glutes, their buttocks are small, in some cases you wonder where it has all gone !  But their quadriceps are massive in comparison in many cases. It is clear that in most of the cases the ratio is not the same as in sprinters.  There is a mismatch. We like to say that their quadriceps are in charge of their hip mechanics, and are certainly not suited to do so.  Now, we know the argument that will arise, that being they are different activities and thus they should be different.  Our only argument there is that the quadriceps should not have such a dominance over the gluteal and hip biomechanics.  Watch our two part hip biomechanics videos on YouTube again.

When we put our distance athletes on our Total Gym slide-squat board to do primitive squat isolations the distance runners have a great deal of difficulty “getting themselves out of the quads and into the glutes”.  The sprinters automatically go right into the glutes, or clearly have a better time of finding the correct pattern in controlling hip extension and eccentric hip flexion during the decent of the squat. 

Here is the bottom line. The glutes should always be in charge over the quadriceps when it comes to hip biomechanics. Mess up this ratio and dominance and problems will occur.  This goes for both distance runners and sprinters, actually all human beings no matter what sport. It has become painfully clear that the cross over gait allows the leg pendulum to shift too far medially and this is controlled largely by the gluteus medius and its synergists on a neutral pelvis and stable core controlling it.  Crossing over is poor gait economy, you must block that faulty cross over collapse.  A good distance runner will come right up to the fence, to the tipping point, but not fall off the proverbial fence.  Go too far, and the injury clock starts ticking.  If you are a runner or even a distance walker and you are crossing over even a little, you need to correct this gait pathology in our humble opinion. You are just not using your glutes correctly and effectively.

( By the way, Here is a drill (link) not to do for a sprinter or any runner for that matter in our opinion, it is driving cross over both mentally and physically. If we had our way he would have run with his foot contact drifting to the outer limits of each marker maintaining a nice vertical pendulum of the limbs from the hip axis, we wouldnt have him run down the line.  We ask our runners to run on either sides of the lanes on the track, not between the lines and in the lane. It is a great place to start. It is just enough to get the feel right.  We know of two coaches doing this from our consultations with them, we know they are on a serious journey to championship seasons. And, when we walk onto their fields and we see all the runners running down the lines and not down the middle of the lanes we smile.  We know it looks crazy.  But sometimes crazy is right !

Shawn and Ivo.  Beating our bloody foreheads against the wall each time we see another cross over runner with hip, knee or foot issues.  You gotta fix the neuromotor pattern problem too !!!!!!!!!!  All the in-clinic rehab and physical therapy in the world will not stave off re-injury if the pattern is not corrected !

whew !  (thanks for hanging in there gang…..long post today !)

Hip Dancing gets this runner to the Olympics

… and some of you thought we might be a few sandwiches short of a picnic when we talked about the value of, and tricks we use, incorporating dance moves into running rehab. Don’t lie, we know you were thinking it ! Remember our last post of 2011 on our experiences with this stuff ?
http://thegaitguys.tumblr.com/
post/15029125468/this-may-be-the-last-blog-post-you-read-from-us

here is a video of the japanese runner doing his Curvy Dancing ?!     http://youtu.be/DvNW4yZNHgM

From Traditional trainers to minimalism…… so, what is the “earth shoe” then ? Will the fad return ? Will we see running shoes go this far ? Afterall, we are at zero drop now ?
So, we all have seen the trend…….…

From Traditional trainers to minimalism…… so, what is the “earth shoe” then ? Will the fad return ? Will we see running shoes go this far ? Afterall, we are at zero drop now ?

So, we all have seen the trend……. minimalism is here and it is not a fad, it is a trend and it is here to stay. It is here to stay because it is not a fad like this shoe above.  The Earth shoe has made 2 resurgences in the last 4 decades. We are likely to see another very soon since this minimalism trend has occurred. Make no mistake though, the minimalism is not a fad, it is a trend and it will be staying. 

So, what is wrong with this shoe ?

Minimalism will remain because we are finally restoring the normal rear foot : forefoot parameters to what we were born with. We were born with the rear and forefoot on the same plane, flat on the ground.  This even playing field, or at least a return to it for many shoe manufacturers, allows the anatomy (both bone and soft tissues such as muscles) to again operate in the fashion it was designed.  Sure the “running form” changes everyone is promoting is important. It is critical to get into good form. But unless the foot’s parts are normalized to the optimal mechanics we were born with even running form changes will not correct 100% of a person’s mechanical issues. 

The minimalism is allowing the rear foot to drop down to the same level of the forefoot, the same operating plane.  This necessitates length in the posterior compartment (calf and achillies mechanism) which will enable the anterior compartment (tibialis anterior and toe extensors) to see more function and thus gain more strength.  This plays well into our long standing theories that stretching of the calf, albeit sometimes necessary to a point, is not the answer for tightness in the calf…..rather putting the foot in a posture to enable the anterior compartment will earn length in the posterior compartment.  Here comes another mantra we use in our offices……. “Gain Anterior strength to achieve Posterior Length”.  Merely stretching the posterior compartment to gain length does not afford anterior strength.  So, it depends if you want a temporary bandaid or a long term fix.  We opt for the fix which is why it is a rarity that you ever hear from us “Mrs. Jones, you need to stretch your calf”.  Instead we teach the solution.

What else comes to mind about minimalism.  Well, again take the shoe above to give an extreme example of what dropping the heel will do.  It will shift your weight bearing posture posteriorly. Go ahead…..stand on the ball of your feet….. your body mass shifts forwards, your low back might arch if you do not have enough abdominals.  IF you then drop the heel you will feel your body posture shift backward and you will feel more glute and more abdominal and neutral pelvis-core posturing. You will also feel a more balanced weightbearing between the forefoot and rearfoot. This is good. These are just some of the things that minimialism does.  There is alot more.  But those are for another time.

In the meantime. The earth shoe. It drops you into rearfoot negative. The rearfoot is lower than your forefoot.  Remind you of anything ? Yup, walking in the sand. The heel sinks more if you load it first.  This will create a drastic change in length-tension relationships between the calf and anterior compartment. It will load the anterior ankle (mortise joint) and can really challenge the shin muscles.  Ever get shin splints or soreness the next day after a long beach walk ?  There is your reason.  So, the Earth Shoe. It is not natural. It puts your rearfoot and forefoot on two separate planes of operation. Or think of it this way…..it raises your forefoot onto a higher plane.  Walk around on your heels with the ball of your foot off the ground.  Feel your anterior muscles challenge ? You might even feel the posterior compartment stretch load a little. And we know that when you put a stretch through a loaded muscle the golgi tendon organ fires to inhibit that muscle….. yup, right when you are about to need it to push off.  Pretty messed up huh ?

If you want to see some messed up mechanics buy your favorite enemy some earth shoes. Look for the knees to hyperextend backwards a little, look for a bouncy vertical gait, look for toe gripping/hammer toe development among other things.  They can be a sneaky vengeful gift. 

Shawn and Ivo….. rediscovering the old groovy trends and hoping everyone stops at zero-drop.  Otherwise watch out for our vengence …   “V” is for Vendetta ! 

Stretching out Plantar Fasciitis

Neuromechanics Weekly: Look to the hammy’s???

“These findings show that while we always consider the tightness of the gastrocnemius/soleus complex and the subsequent restricted ankle motion from this equinus, we also need to consider the role of the hamstrings,” said Jonathan Labovitz, DPM, lead author and associate professor at Western University of Health Sciences, Pomona, CA.

this article from Lower Extremity Review, concludes “After controlling for covariates, participants (86 of 210 feet) with hamstring tightness were 8.7 times as likely to experience plantar fasciitis (p < .0001) as participants without hamstring tightness. Patients with a BMI >35 were 2.4 times as likely as those with a BMI <35 to have plantar fasciitis.”

The question is why?

They go on to say “ If you can’t get dorsiflexion at your talo-crural joint, this often drives dorsiflexion at other joints and that is going to cause collapse of the longitudinal arch of the foot, loading the plantar fascia with increased tensile stress.”

So, loss of ankle rocker leads to increased midfoot pronation, which loads the plantar fascia. That sounds pretty logical to us. We are sure you are thinking a loss of hip extension may do the same thing. Correct. Or you may say ” The calves may be tight so the medial gastroc can invert the rearfoot to correct for too much midfoot pronation and the foot can be supinated"…and you would be correct again.

So why are the tight hammys driving the bus? Or are they?

We remember the hams are a 2 joint muscle, and with the foot in a closed chain position (ie, on the ground); they flex the thigh on the lower leg and tilt the pelvis posteriorly (ie reduce the lordosis). They are FLEXORS which are active from late swing phase, just prior to heelstrike (initial contact) and a little nudge just prior to toe off (preswing) to help extend the thigh. 

The tricep surae are FLEXORS and are supposed to be active from loading response till almost pre swing, with a burst of activity at heel lift (terminal stance). 

So they take turns, and are not firing (normally) at the same time (or maybe have a small overlap). Going from heel strike to heel strike, the hammys fire 1st.

So IF the two are related, it could be a neurological sequencing issue. How often does that happen? The literature says (and there aren’t many studies) that you can change the order of recruitment of motor units ( the nerve and the muscle fibers it innervates), but not (usually) individual muscles. So probably not.

OK, how about plan B?

The hams and tricep surae are all flexors, correct? What is the innervation to the hamstrings and tricep surae? Hmm….Hamstrings, mostly tibial branch of the sciatic nerve, short head of biceps femoris is the common peroneal: L5-S2. How about the tricep surae? Tibial nerve, mostly S1-S2. I think I see a trend here. Common neurological overlap of FLEXOR muscles.

So are the hams driving the bus? Probably not, but neither are the gastroc/ soleus. The FLEXORS are driving the bus, and excitation of that common neuronal pool is probably causing the tightness

Ivo and Shawn….Uber footgeeks of the web. Dicing and slicing through the literature so you don’t have to.

Proof that women are not unstable at the time of menstruation.
On the subject of proprioception, here is something we found interesting while on a quest for another article. 1st, we had found an article in the NY Times blog, talking about training c…

Proof that women are not unstable at the time of menstruation.

On the subject of proprioception, here is something we found interesting while on a quest for another article. 1st, we had found an article in the NY Times blog, talking about training considerations of women during their monthly cycle.

They state: “There may, however, still be reasons a woman to consider her period when planning training. A study published this year by scientists at the University of Melbourne in Australia, for instance, found that when women’s estrogen levels were at their highest, around the time of ovulation, they landed subtly differently while hopping than at other times of the month. Their feet splayed, the arch collapsing just a little bit more than it did when their estrogen levels were lower. The women also seemed, to a small degree, wobblier. “We contend that the changes in foot biomechanics may be due to the effects of estrogen on soft tissue and/or the brain,” said Adam Leigh Bryant, a senior lecturer at the University of Melbourne and lead author of the study.”

This says, in a nutshell, that women are not unstable around the time of menstruation (dispelling many common myths to the contrary) but rather, they are unstable around the time of their ovulation (proprioceptively speaking, of course). Women on monophasic contraceptives showed less variability (greater stability) and therefore may be more less injury prone.

Of course we pulled the study (abstract below). We found it interesting that it may actually be a neurological/cortical phenomenon, rather that muscle estrogen receptor based. What is the advantage of less proprioceptive awareness with increased estrogen levels? Maybe (in a bit of a stretch), it was for propagation of the species. If the women can’t get away, then they are more likely to be caught (or less likely to be able to run…)

The Gait Guys….Sifting through the literature and sometimes poking a little fun at it.

Ivo and Shawn.

 

http://www.ncbi.nlm.nih.gov/pubmed/20857138

Eur J Appl Physiol. 2011 Feb;111(2):245-52. Epub 2010 Sep 21.

Estrogen-induced effects on the neuro-mechanics of hopping in humans.

Source

Centre for Health, Exercise and Sports Medicine, School of Physiotherapy, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, VIC, 3010, Australia. albryant@unimelb.edu.au

Abstract

Estrogen receptors in skeletal muscle suggest a tissue-based mechanism for influencing neuromuscular control. This has important physiological implications for both eumenorrheic women with fluctuating estrogen levels and those with constant and attenuated estrogen levels, i.e., women using the monophasic oral contraceptive pill (MOCP). This study examined the effects of endogenous plasma estrogen levels on leg stiffness (K (LEG)) and foot center of pressure (COP) during hopping. Nineteen females (Age = 28.0 ± 4.2 years, Ht = 1.67 ± 0.07 m, Mass = 61.6 ± 6.8 kg) who had been using the MOCP for at least 12 months together with 19 matched, female, non-MOCP users (Age = 31.9 ± 7.3 years, Ht = 1.63 ± 0.05 m, Mass = 62.5 ± 5.9 kg) participated. Non-MOCP users were tested at the time of lowest (menstruation) and highest (≈ ovulation) estrogen whilst MOCP users were tested at Day 1 and Day 14 of their cycle. At each test session, K (LEG) (N m(-1) kg(-1)) and foot COP path length (mm) and path velocity (mm s(-1)) were determined from ground reaction force data as participants hopped at 2.2 Hz on a force plate. Statistical analysis revealed no significant (p < 0.05) differences for K (LEG). In contrast, significantly higher COP path length (30%) and COP path velocity (25%) were identified at ≈ ovulation compared to menstruation in the non-MOCP users. Whilst there was no evidence of an estrogen-induced effect on K (LEG); significantly elevated estrogen at ≈ ovulation presumably increased extensibility of connective tissue and/or diminished neuromuscular control. Consistent lower limb dynamics of MOCP users demands less reliance on acutely modified neuromuscular control strategies during dynamic tasks and may explain the lower rate of lower limb musculoskeletal injuries in this population compared to non-MOCP users.

“There may, however, still be reasons a woman to consider her period when planning training. A study published this year by scientists at the University of Melbourne in Australia, for instance, found that when women’s estrogen levels were at their highest, around the time of ovulation, they landed subtly differently while hopping than at other times of the month. Their feet splayed, the arch collapsing just a little bit more than it did when their estrogen levels were lower. The women also seemed, to a small degree, wobblier. “We contend that the changes in foot biomechanics may be due to the effects of estrogen on soft tissue and/or the brain,” said Adam Leigh Bryant, a senior lecturer at the University of Melbourne and lead author of the study.”

The Confusion of Shoe Science (Part 5 of 5): Narrowing the Gap Between Science, Manufacturer, Retail and Consumer

This is an important series of lectures / debate.  This event occurred on December 6th, 2011 at The Running Event which we also lectured at.  The result of this series of talks, which we will post 2-5 sequentially daily here on our blog, was an underground heated dialogue between some of the speakers. 

We have come to greatly respect Blaise Dubois for his vast wealth of knowledge and his unbiased standpoint. Blaise is a physicial therapist with worldwide respect for his knowledge and experience.  Unlike some of the other speakers you will hear in the coming days, he had no vested interest other than sharing the facts and myths in this field.  This is why we have enjoyed our growing relationship with Blaise, because we too have no vested interest with any company other than the truth. 

Watch these videos and learn, and make your own conclusions.  But, if you are a runner or shoe store owner or staff, you need to watch these and open your mind and consider that what you are being told by your shoe vendors might not always be the truth.  Educate yourself, ask the hard questions of your shoe vendors and companies and make your own conclusions. 

Shawn and Ivo  ……. bringing this stuff to you so you do not have to find it on your own.

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Thinking about throwing away those old running shoes? Think again. A recent study looking at plantar pressures in new vs old shoes reveled that newer shoes had higher perssures, assumedly due to increased stiffness of the shoe.

This definitely is a fly in the ointment about changing your shoes every 500 miles and supports a slow break in for any shoe.

Ivo and Shawn. Yes, we are shoe geeks…even on a Sunday

The Confusion of Shoe Science (Part 4 of 5): Narrowing the Gap Between Science, Manufacturer, Retail and Consumer

This is an important series of lectures / debate.  This event occurred on December 6th, 2011 at The Running Event which we also lectured at.  The result of this series of talks, which we will post 2-5 sequentially daily here on our blog, was an underground heated dialogue between some of the speakers. 

* Here is the problem. Shoes are not designed around the extreme foot types at either end of the Bell Curve.  They are designed for the foot in a normative range. Simon says here that we can manipulate the shoe to determine of the foot can pronate or supinate.  That is what shoes have been doing all along ! This is what the dual density is used for. This is what the crash zone is used for, etc etc.  This was a pretty commercialized closing by Simon, he spent alot of time talking about Asics. There was little “narrowing of the gap” for us.

Watch these videos and learn, and make your own conclusions.  But, if you are a runner or shoe store owner or staff, you need to watch these and open your mind and consider that what you are being told by your shoe vendors might not always be the truth.  Educate yourself, ask the hard questions of your shoe vendors and companies and make your own conclusions. 

Shawn and Ivo  ……. bringing this stuff to you so you do not have to find it on your own.

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The Sole Truth and Nothing but the Truth

Thicker soles mean more muscle activity. Nothing new here. We have posted on the fallacy of increased cushioning and decreased impact many times. Here is another supporting study.


Here are part of the results:Compared to the barefoot condition, there is an increase in the magnitude of muscle contraction on wearing shoes, which further increases with thickening shoe soles.”

and the conclusion...“Footwear with increasing shoe sole thickness evokes a correspondingly stronger protective eversion response from the peroneus longus to counter the increasing moment at the ankle-subtalar joint complex following sudden foot inversion. Hence, fashion footwear with thicker sole is likely to increase the risk of lateral ligament injury of the ankle when such protective response is overwhelmed. Similarly, the clinicians need to be cautious regarding the amount of shoe raise that they could provide for patients with limb length discrepancy without any detrimental untoward side effects.”


We remember the peroneus longus attaches from the upper, lateral fibula, traveling down the fibular shaft, around the lateral malleolus and attaching to the base of the 1st  1st metatarsal and lateral cunieform. It fires from just prior to heel strike to terminal stance, assisting in eversion of the foot and cuboid,  locking the lateral column of the foot during supination, and plantar flexes the 1st ray (brings the medial tripod down to the ground). More sole = More activity = More potential for injury

more on peroneus here


The Gait Guys. Bringing you the science of shoes and the impact on gait, every day.

 

http://www.ncbi.nlm.nih.gov/pubmed/22017890

Foot Ankle Surg. 2011 Dec;17(4):218-23. Epub 2010 Sep 17.

The influence of shoe sole’s varying thickness on lower limb muscle activity.

Source

Institute of Motion Analysis & Research, Department of Orthopaedic & Trauma Surgery, TORT Centre, Ninewells Hospital & Medical School, University of Dundee, Dundee, DD1 9SY, Scotland, UK.

Abstract

BACKGROUND:

The lateral ligament injury of the ankle is acknowledged to be the most common ankle injury sustained in sport. Increased peroneus longus muscle contraction in the shod population has already been documented. This study aimed to quantify the effect of shoe sole’s varying thickness on peroneus longus muscle activity.

METHODS:

Electromyographic recordings of the peroneus longus muscle activity following unanticipated inversion of the foot from 0° to 20° in a two-footplate tilting platform were collected from 38 healthy participants. The four test conditions were: barefoot, standard shoe, and shoes with 2.5 cm and 5 cm sole adaptation respectively.

RESULTS:

Compared to the barefoot condition, there is an increase in the magnitude of muscle contraction on wearing shoes, which further increases with thickening shoe soles. The peroneus longus was responding earlier in the shod conditions when compared to the barefoot, although the results were variable within the three shod conditions.

CONCLUSION:

Footwear with increasing shoe sole thickness evokes a correspondingly stronger protective eversion response from the peroneus longus to counter the increasing moment at the ankle-subtalar joint complex following sudden foot inversion. Hence, fashion footwear with thicker sole is likely to increase the risk of lateral ligament injury of the ankle when such protective response is overwhelmed. Similarly, the clinicians need to be cautious regarding the amount of shoe raise that they could provide for patients with limb length discrepancy without any detrimental untoward side effects.

Copyright © 2010. Published by Elsevier Ltd.

The Confusion of Shoe Science (Part 3 of 5): Narrowing the Gap Between Science, Manufacturer, Retail and Consumer

* note, if you rushed ahead and watched PART 3 on the IRRC youtube page,  you will now want to watch this critiqued version by Blaise Dubois. This is important that you watch this version so you can get a clearer truth and less of a commerical bias, in our opinion.

This is an important series of lectures / debate.  This event occurred on December 6th, 2011 at The Running Event which we also lectured at.  The result of this series of talks, which we will post 2-5 sequentially daily here on our blog, was an underground heated dialogue between some of the speakers. 

The Gait Guys have no vested interest with any company other than the truth. In our opinion Simon Bartold’s lecture here is very biased towards the company he works for, Asics.

Watch these videos and learn, and make your own conclusions.  But, if you are a runner or shoe store owner or staff, you need to watch these and open your mind and consider that what you are being told by your shoe vendors might not always be the truth.  Educate yourself, ask the hard questions of your shoe vendors and companies and make your own conclusions. 

* If you wish to watch this version without the important additions added by Blaise, you can go here and which Simon’s commercially biased lecture unabridged. click here

Shawn and Ivo  ……. bringing this stuff to you so you do not have to find it on your own.

The Confusion of Shoe Science (Part 2 of 5): Narrowing the Gap Between Science, Manufacturer, Retail and Consumer

This is an important series of lectures / debate.  This event occurred on December 6th, 2011 at The Running Event which we also lectured at.  The result of this series of talks, which we will post 2-5 sequentially daily here on our blog, was an underground heated dialogue between some of the speakers. 

We have come to greatly respect Blaise Dubois for his vast wealth of knowledge and his unbiased standpoint. Blaise is a physicial therapist with worldwide respect for his knowledge and experience.  Unlike some of the other speakers you will hear in the coming days, he had no vested interest other than sharing the facts and myths in this field.  This is why we have enjoyed our growing relationship with Blaise, because we too have no vested interest with any company other than the truth. 

Watch these videos and learn, and make your own conclusions.  But, if you are a runner or shoe store owner or staff, you need to watch these and open your mind and consider that what you are being told by your shoe vendors might not always be the truth.  Educate yourself, ask the hard questions of your shoe vendors and companies and make your own conclusions. 

Shawn and Ivo  ……. bringing this stuff to you so you do not have to find it on your own.

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Boots make the Man (or the Woman)

If you had any doubts about shoes changing ground reaction forces (GRF’s), then read no further.GRF’s are one of the factors considered by some sources as being injurious.

Tennis shoes had the most ground reaction forces

Army boots came in a narrow second

Bare feet had the least forces by a significant amount

Incidently, the amount of the valgus in the knees on landing was not significantly different among the 3 cases.

Hmmm. We need to think before recommending a shoe.

Ivo and Shawn. The Gait Guys. Sifting through the literature so you don’t have to. Yes, we are still bald, middle aged and good looking….

J R Army Med Corps. 2011 Sep;157(3):218-21.

A kinematic and kinetic analysis of drop landings in military boots.

Abstract

OBJECTIVE:

The purpose of this study was to examine knee valgus in drop landings during three different footwear conditions and to examine the ground reaction forces exhibited during the drop landing in the three different footwear conditions.

METHODS:

Sixteen male and female Reserve Officer Training Corps (ROTC) university undergraduate cadets (21 +/- 3 yrs, 79 +/- 12 kg, and 172 +/- 10 cm) volunteered to participate in the study. Kinematic data were collected while participants performed drop landings in three conditions: bare feet, tennis shoes, and issued military boots.

RESULTS:

Significant differences among footwear for ground reaction forces (bare feet: 1646 +/- 359%, tennis shoe: 1880 +/- 379%, boot: 1833 +/- 438%; p < 0.05) were found, while there was no significant difference in knee valgus among footwear.

CONCLUSIONS:

Though footwear conditions did not affect knee valgus, they did affect ground reaction forces. Participants in this study had yet to receive any military training on how to land properly from a specified height. Further research should be completed to analyze the kinematics and kinetics of the lower extremity during different landing strategies implemented by trained military personnel in order to better understand injury mechanisms of drop landings in this population. It is likely that injury prevention landing techniques would be beneficial if these were employed by the military and not just in the sporting community.

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Shoe News You Can Use

Pronation is dorsiflexion, eversion and abduction, It is a term usually used to refer to midfoot motion. It occurs as the friction of the heel with the ground causes the talus to slide anteriorly on the calcaneus, as it does so, it plantar flexes, adducts and everts. this motion causes a medial spin of the talus, which, in turn, causes an internal spin of the tibia (see above).

Pronation is a natural motion which  is one of the 4 shock absorbing mechanisms we have to attenuate force (pronation, ankle dorsiflexion,knee flexion and thigh flexion). Some pronation is necessary for normal gait. Over or under pronation appear linked to increased likelihood of injury. Of the 2, over pronation is the most treated (possibly wrongly so) and one intervention is motion control shoes.

Motion control shoes usually have a feature (medial posting, varus positioning, dual density midsoles, increased lateral flare, etc) which attenuates or delays pronation.

Along those lines, an in light of our latest series of posts, we thought you may find this study interesting. Results were as follows: “A one-tailed paired t-test indicated a statistically significant decrease in the total range of proximal tibial rotation when a motion control shoe was worn (mean difference 1.38°, 95% confidence interval 0.03 to 2.73, P=0.04).”

So, motion control shoes decreased motion about 1-1.5 degrees. The average amount of midfoot motion is 4-8 degrees. Our question to you is “Is that enough, or is that significant?”

We think so, especially in some cases. A few degrees can make all the difference. There appears a time and place for motion control shoes, but on our opinion, they are grossly over prescribed for problems that are usually able to be treated more conservatively.

The Gait Guys. Promoting Gait and Foot literacy…everywhere

Physiotherapy. 2011 Sep;97(3):250-5. Epub 2011 Feb 2.

Effect of motion control running shoes compared with neutral shoes on tibial rotation during running.

Abstract

OBJECTIVE: To determine whether a motion control running shoe reduces tibial rotation in the transverse plane during treadmill running.

DESIGN: An experimental study measuring tibial rotation in volunteer participants using a repeated measures design.

SETTING: Human Movement Laboratory, School of Health Professions, University of Brighton.

PARTICIPANTS: Twenty-four healthy participants were tested. The group comprised males and females with size 6, 7, 9 and 11 feet. The age range for participants was 19 to 31 years.

MAIN OUTCOME MEASURES: The total range of proximal tibial rotation was measured using the Codamotion 3-D Movement Analysis System.

RESULTS: A one-tailed paired t-test indicated a statistically significant decrease in the total range of proximal tibial rotation when a motion control shoe was worn (mean difference 1.38°, 95% confidence interval 0.03 to 2.73, P=0.04).

CONCLUSIONS: There is a difference in tibial rotation in the transverse plane between a motion control running shoe and a neutral running shoe. The results from this study have implications for the use of supportive running shoes as a form of injury prevention.

Copyright © 2010 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

The Confusion of Shoe Science (Part 1 of 5): Narrowing the Gap Between Science, Manufacturer, Retail and Consumer

This is an important series of lectures / debate.  This event occurred on December 6th, 2011 at The Running Event which we also lectured at.  The result of this series of talks, which we will post 2-5 sequentially daily here on our blog, was an underground heated dialogue between some of the speakers. 

We have come to greatly respect Blaise Dubois for his vast wealth of knowledge and his unbiased standpoint. Blaise is a physicial therapist with worldwide respect for his knowledge and experience.  Unlike some of the other speakers you will hear in the coming days, he had no vested interest other than sharing the facts and myths in this field.  This is why we have enjoyed our growing relationship with Blaise, because we too have no vested interest with any company other than the truth. 

Watch these videos and learn, and make your own conclusions.  But, if you are a runner or shoe store owner or staff, you need to watch these and open your mind and consider that what you are being told by your shoe vendors might not always be the truth.  Educate yourself, ask the hard questions of your shoe vendors and companies and make your own conclusions. 

Shawn and Ivo  ……. bringing this stuff to you so you do not have to find it on your own.

Neuromechanics Weekly: Pain Matters


We know that joint swelling (and thus inflammation) inhibits the contraction of the muscle which crosses the joint from the landmark work of Iles and Stokes back in the late 80&rsquo;s. Now here is a paper stati…
Neuromechanics Weekly: Pain Matters


We know that joint swelling (and thus inflammation) inhibits the contraction of the muscle which crosses the joint from the landmark work of Iles and Stokes back in the late 80’s. Now here is a paper stating that pain does the same thing


This tells us that there is an axon collateral from the primary pain neuron (the “C” fiber) that somehow inhibits the alpha moto neuron, similar to a flexor reflex, as pictured. his is most likely through affecting the gamma moto neuron (which goes to the spindles) rather than the alpha motoneuron; so the “sensitivity” of the muscle is changed (remember, spindles detect length changes, golgi’s tension).


So what does this mean to us and gait? It tells us that pain will inhibit the activity (voluntary and involuntary) of the ability for one to use their muscles, especially those crossing the joint in questions. Be aware of inflammation (painful or non painful) or the painful joint, which can contribute to a compensation pattern.


Ivo and Shawn…The Gait Guys. Making your life less painful and more functional….




Muscle Nerve. 2000 Aug;23(8):1219-26.

Inhibition of motor unit firing during experimental muscle pain in humans.

Source

Center for Sensory-Motor Interaction, Orofacial Pain Laboratory, Aalborg University, Denmark.

Abstract

Electromyographic activity was recorded in the masseter muscle to investigate whether the firing characteristics of single motor units (SMUs) were affected by muscle pain. Capsaicin was injected into the masseter to induce pain. The interspike interval (ISI) and recruitment threshold of SMUs were measured while subjects performed isometric contractions at 5, 7.5, 10, 15, and 20% of maximum voluntary contraction. All subjects were able to maintain a stable isometric force during pain, but the mean ISI was significantly increased without changing the recruitment threshold. In all the experimental conditions, the firing frequency increased with increasing force, and SMUs recruited at low force fired at higher rates for all force levels. These results suggest that acute stimulation of nociceptive muscle afferents inhibits SMU activity without changing recruitment order in the homonymous muscle.

Copyright 2000 John Wiley & Sons, Inc.