On the topic of endurance training.....

On the topic of endurance training (which we discussed on this weeks PODcast, forthcoming in the next day or so; we have both been extraordinarily busy in our clinics); if you are a well trained athlete (ie endurance junkie), how might this effect your running gait?

So, you run 103 miles with an elevation change of over 31,000 feet, how do you think you would fare? These folks were tested pre and 3 hours post race on a 22 foot long pressure walkway at about 7.5 miles per hour. Here’s how this group of 18 folks did:

  1. increased step frequency
  2. decreased “aerial” time
  3. no change in contact time
  4. decrease in downward displacement of the center of mass
  5. decrease in peak vertical ground reactive force
  6. increased vertical oscillation
  7. leg stiffness remained unchanged

So what does this tell us?

  • wow, that is a lot of vertical
  • holy smokes, that is really far
  • don’t know how I would do with a race like that
  • they are fatigued (1, 2, 6)
  • they are trying to attenuate impact forces (2, 3, 4, 5, 7)

The system is trying to adapt the best it can. If you were to do a standard hip screen test (like we spoke about here)  you would probably see increased horizontal drift due to proprioceptive fatigue. Remember that proprioception (our bodies ability to sense its position in space) makes the world go round. Proprioception is dependent on an intact visual system (see our post yesterday) , an intact vestibular system and muscle and joint mechanoreceptors functioning appropriately). We would add here that central nervous system fatigue (ie central processing both at the cord and in the cortex) would probably play a role as well.

The take home message? The human machine is a neuro mechanical marvel and much more complex than having the right shoe or the right running technique. Training often makes us more competent and efficient, but everything has it limits.

The Gait Guys. Making it real with each and every post.

all material copyright 2013 The Gait Guys/ The Homunculus Group

J Biomech. 2011 Apr 7;44(6):1104-7. doi: 10.1016/j.jbiomech.2011.01.028. Epub 2011 Feb 20.

Changes in running mechanics and spring-mass behavior induced by a mountain ultra-marathon race.

Source

Université de Lyon, F-42023 Saint-Etienne, France. jean.benoit.morin@univ-st-etienne.fr

Abstract

Changes in running mechanics and spring-mass behavior due to fatigue induced by a mountain ultra-marathon race (MUM, 166km, total positive and negative elevation of 9500m) were studied in 18 ultra-marathon runners. Mechanical measurements were undertaken pre- and 3h post-MUM at 12km h(-1) on a 7m long pressure walkway: contact (t©), aerial (t(a)) times, step frequency (f), and running velocity (v) were sampled and averaged over 5-8 steps. From these variables, spring-mass parameters of peak vertical ground reaction force (F(max)), vertical downward displacement of the center of mass (Δz), leg length change (ΔL), vertical (k(vert)) and leg (k(leg)) stiffness were computed. After the MUM, there was a significant increase in f (5.9±5.5%; P<0.001) associated with reduced t(a) (-18.5±17.4%; P<0.001) with no change in t©, and a significant decrease in both Δz and F(max) (-11.6±10.5 and -6.3±7.3%, respectively; P<0.001). k(vert) increased by 5.6±11.7% (P=0.053), and k(leg) remained unchanged. These results show that 3h post-MUM, subjects ran with a reduced vertical oscillation of their spring-mass system. This is consistent with (i) previous studies concerning muscular structure/function impairment in running and (ii) the hypothesis that these changes in the running pattern could be associated with lower overall impact (especially during the braking phase) supported by the locomotor system at each step, potentially leading to reduced pain during running.

Copyright © 2011 Elsevier Ltd. All rights reserved.

http://www.ncbi.nlm.nih.gov/pubmed/21342691

How we keep our head steady while we run.

Evolved to run: How we keep our noodle steady while we run.

Have you ever given thought to your head movements during running or walking ? Ever wonder why the world doesn’t seem to bound around as we move ? Wonder why things look different through your eyes when you yourself are running as compared to when you are watching the nauseating jerky video of someone wearing a camera on their head ?
Bryce Vickmark for The New York Times interviewed Dr. Lieberman of the Harvard Nature study…. here is a quote from that interview.
“We (Lieberman) realized that there were special features in the human neck that enable us to keep our heads still. That gives us an evolutionary advantage because it helps us avoid falls and injuries. And this seemed like evidence of natural selection in our ability to run, an important factor in how we became hunters rather than just foragers and got access to richer foods, which fueled the evolution of our big brains.”

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Gait Guys say this….. “The ability to see clearly while moving / running / hunting is a well rooted primitive neurologic function in man. The visual-motor system (oculomotor system) is capable of assimilating the visual information and making calculations for the small head displacements that occur with movement via neural mechanisms that control three-dimensional head posture while coordinating three-dimensional eye orientation. The body’s movements as a whole (eye, head and body) are part of a coordinated series of sensory-motor events that are used to voluntarily reorient the axis of gaze between objects.  Body movements themselves can make a predictable contribution to gaze shifts and one study (link) has shown that single neurons (yes, one small neuron all by itself) can code motor commands to move the body as well as the head and eyes.  It is a finely tuned system, an amazing system.  One we rarely appreciate anymore since running during a hunt for food no longer occurs in urban America.  Of course this function is seamlessly tested everyday in athletes, unless of course you are a football or other impact sport athlete, and have accelerated your noggin one too many times.  Ask any aging boxer or ex-football player how their visual-motor system is doing ! (On a slight tangent since there is so much info in the media on concussive syndromes these days, here is support for those dropped endzone passes in the concussed wide receivers...LINK and. LINK)

NY Times link: for the Lieberman article.

We are The Gait Guys…….. running and hunting outside the box everyday, looking for answers.

Unstable shoes provide more activation of selected lower extremity muscles and increased postural sway WHILE STANDING. Does this really surprise us?
 &ldquo; &hellip;it was shown that standing in the unstable shoe increased activity of the flexor di…

Unstable shoes provide more activation of selected lower extremity muscles and increased postural sway WHILE STANDING. Does this really surprise us?

 “ …it was shown that standing in the unstable shoe increased activity of the flexor digitorum longus, peroneal (PR) and anterior compartment (AC) muscles of the lower leg. No activity differences for the larger soleus (SOL) were identified between the stable and unstable shoe conditions.”. In English that means the muscles on the front, back and outside of your lower leg.

It goes on to say “Postural sway was greater while standing in the unstable shoe compared to barefoot and the stable control shoe.” and “Postural sway while standing in the unstable MBT shoe also decreased over the 6-week accommodation period.” Postural sway is one way of measuring proprioception or body position awareness. 

The key words here are “WHILE STANDING”. It DOES NOT SAY WALKING. We have talked about rockered shoes in numerous previous posts and we have always maintained that in the right circumstances, it can be a good thing, but not necessarily something you should go do your grocery shopping or gym workout in.

Gait Posture. 2010 Jun;32(2):215-9. doi: 10.1016/j.gaitpost.2010.04.018. Epub
2010 May 23.

Standing in an unstable shoe increases postural sway and muscle activity of
selected smaller extrinsic foot muscles.

Landry SC, Nigg BM, Tecante KE.

Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, 2500
University Drive N.W., Calgary, Alberta, Canada T2N 1N4. scott.landry@acadiau.ca

Inactivity or the under-utilization of lower limb muscles can lead to strength
and functional deficits and potential injury. Traditional shoes with stability
and support features can overprotect the foot and potentially contribute to the
deterioration of the smaller extrinsic foot muscles. Healthy subjects (n=28)
stood in an unstable MBT (Masai Barefoot Technology) shoe during their work day
for a 6-week accommodation period. A two-way repeated measures ANOVA was used to 
determine (i) if unstable shoe wear increased electromyographic (EMG) activity of
selected extrinsic foot muscles and increased postural sway compared to standing 
barefoot and in a stable control shoe and (ii) if postural sway and muscle
activity across footwear conditions differed between a pre- and
post-accommodation testing visit. Using an EMG circumferential linear array, it
was shown that standing in the unstable shoe increased activity of the flexor
digitorum longus, peroneal (PR) and anterior compartment (AC) muscles of the
lower leg. No activity differences for the larger soleus (SOL) were identified
between the stable and unstable shoe conditions. Postural sway was greater while 
standing in the unstable shoe compared to barefoot and the stable control shoe.
These findings suggest that standing in the unstable MBT shoe effectively
activates selected extrinsic foot muscles and could have implications for
strengthening and conditioning these muscles. Postural sway while standing in the
unstable MBT shoe also decreased over the 6-week accommodation period.

Copyright 2010 Elsevier B.V. All rights reserved.

One simple hip screen that gives you lots of information.

This is the one leg standing test. We use it as a hip function (abduction) screen(as well as an exercise), to see if a person’s gluteus medius is working in a functional situation (as opposed to manual muscle testing).

As you may remember (don’t remember? Click here), the gluteus medius fires throughout stance phase (ie; when the foot is on the ground). It keeps the pelvis level while the foot is on the ground and works in conjunction with the opposite quadratus lumborum muscle (if you have not read up on this, please see our groundbreaking work on the problematic cross over gait, found here, here and here).

The test is simple; try it on yourself while watching yourself in a mirror. Stand on one leg on your foot tripod (the heel, base of big toe and base of little toe). Raise the opposite foot off the ground by flexing the thigh. Observe.

You should see the pelvis remaining level with no shift of the torso or hips. 

Watch for:

  • ·      Pelvic drift to the side you are standing on
  • ·      Pelvis drop on the side opposite you are standing on
  • ·      Body lean to the side you are standing on
  • ·      Excessive hiking of the opposite, non weight bearing hip
  • ·      Any combination of the above

 

Seeing any (or all) of these means the gluteus medius is probably having some trouble.  The reason we say probably is that a person with a hip problem (like arthritis) or an anatomically short leg may do some of these things in compensation.

The question you are hopefully asking is why do they drift, lean, hike, etc? Not everything you see is muscle weakness per se.

  • ·      Maybe they have a balance issue
  • ·      Maybe they have a disc injury
  • ·      Maybe they have injury to the nerve going to the gluteus medius
  • ·      Maybe they have a knee/ankle/foot issue
  • ·      And the list goes on…

So, if it were a muscle weakness, how could you fix it? Determine the cause. Begin at the bottom with foot exercises: tripod standing, lift/spead/reach with the toes etc. Then have them repeat the exercise IN A MIRROR, maintaining a level pelvis. Yes, it is that simple. Now see if they can translate that to their gait cycle. If so, great. If not, start again and repeat till they can.

The Gait Guys. Making it real, each and every day.

all material copyright 2013 The Gait Guys/ The Homunculus Group. All rights reserved. Please ask before using!

The Naked Foot: Thoughts for the Shoe Minimalist

Authors: Dr. Shawn Allen, Dr. Ivo Waerlop, Coach Chris Korfist

This may be one of the very first articles we ever wrote for The Gait Guys. It must be 7-8 years old now, before the barefoot-minimalist craze ever started. It is a bit dated, but we think that it was time to revisit its contents. You will see that many of our early core principles have not changed and you can see the thought process of where the fads and trends were projected to go.  Wind your mind back a near decade, and read on !

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If you want to follow the fad craze these days, just look to companies like Vibram and Nike. Vibram is the company that has brought you the soles and treads of many of the shoes you have worn over the years and of course Nike are the people who first brought you the “running shoe” as we know it today. Nike first brought us the waffle bottom trainer, the cross trainer, air pockets, “shocks” and, the Air Jordan and now their barefoot minimalist series, the Nike Free. Now, we are sure not many of you have heard of the “Vibram Five Fingers” barefoot slip-on ‘shoe’ but virtually everyone who runs in some manner has seen and heard about the Nike Free. What initially stymied us when they first came out was the obvious question of “Why would the same people who sell us the shoes, and give us so many varieties and categories to choose from, now be advocating that we train barefoot, or close to it? ” Or are they ?

  • (Addendum:  this article was originally written long ago, at the start of this fad, the fad that has become a trend.  The article traveled fast around the internet and garnered us much attention including a gig with Vibram as consultants.  But that was then, this is now.  We, and the trend have come a long way, and so has the research.  Some supportive for the trend, some disagreements and plenty of controversy.  The remainder of this article has been unedited, hence its tense and outdated verbiage, shoe types and research.  But we thought it was time to review before moving ahead.)

The Nike version they are pushing, first the Nike Free 5 and now down to the Nike Free 3, has a light weight thin flexible sole and thin vamp top cover material whoís purpose is to merely hold the shoe onto the foot. The Vibram device, which is a fascinating yet simple slipper, is even more simplistic but has some brilliance built right into its heart. It is merely a rubber sock with compartments for each individual toe but that is part of its brilliance. So why would Nike and now Vibram go against their own creations and advocate that we begin walking and running barefoot, or at least become more “shoe-minimalists” after decades of building shoe and sole lines that previously were designed for various conditions, foot types and activities ? There appears to be sound moral reasoning if you delve into the research, but you have to look closely and you have to be careful you do not have one of those foot types that could lead to problems with this type of footwear (but that is a topic for another article to come soon, see Part II).

Barefoot theories are nothing new. In 1960 Abebe Bikila, perhaps the greatest barefoot runner of all time, won the first of his consecutive gold medals without shoes setting a world record of 2:15:17. Englandís Bruce Tulloh was setting overseas records into the 1960’s running unshod, skin to the ground. Today Ken Bob Saxton is one of the most visible barefoot marathoners, long beard and all, and is an advocate of the technique.

With the introduction of the Nike Free, the interest in barefoot running resurfaced at the turn of the century. An article by Michael Warburton, published as an internet paper on barefoot theories, seemed to spark some of the resurgence of the method of running. In his brilliant paper he had some interesting thoughts and pointed out some noteworthy facts. He indicated that research showed that an extra mass of 100 grams attached to the foot diminished the economy of running by one percent. Thus, two 10 ounce shoes (the weight of a lightweight training shoe) could compoundingly cripple you by more than five percent in efficiency. In tangible terms that could be more than six minutes tacked onto a world class marathoner, taking a world record time to a mere first group finishing time. So, it is a question of weight and time, or is there something more ?

To get started with some hard and simple research facts, current research has been conducted showing that plantar (bottom of the foot) sensory feedback plays a central role in safe and effective locomotion, that more shoe cushioning can lead to higher impact forces on the joints and higher risk of injury, that unshod (without shoes) lowers contact time versus shod running, that there are higher braking and pushing impulses in shod versus unshod running, that unshod running presents a reduction of impact peak force that would reduce the high mechanical stress that occurs during repetitive running and that the unshod foot induces a neural-mechanical adaptation which could enhance the storage and restitution of elastic energy at ankle extensor level. These are only some of the research findings but they are some of the more significant ones. These issues will not only support injury management benefits for the unshod runner but increase speed, force and power output.

Stepping backwards in time a little, in the caveman days things were different. The foot was unshod (without shoes) from the moment of the first step until one’s dying day, and thus the foot developed and looked different. The sole of the foot was thicker and callused due to the constant contact with rough and offending surfaces thus preventing skin penetration, the foot proper was more muscular and it may have been wider in the forefoot and the toes were likely slightly separated due to the demands of gripping which would obviously necessitate increase muscular strength and bulk to the foot intrinsic muscles. It was the constant input of uneven and offending surfaces such as rocks, twigs, mud, foliage and debris that stimulated the bottom of the foot, and thus the intrinsic muscles, sensing joint positions and relaying those variations to the brain for corresponding descending motor changes and adaptations to maintain protection and balance. The foot simply worked different, it worked better, it worked more like the engineering marvel that it truly is. The foot was uncovered and the surfaces we walked on were uneven and challenging. However, as time went on, man decided to mess with a good thing. He took a foot that was highly sensitive, a virtual sensory organ with a significant sensory and motor representation in the brain (only the hands and face have more brain representation as represented by the sensory and motor homunculus of the brain) and he not only covered it up with a slab of leather or rubber but he then flattened and then paved not only his world, but also his home, with black hard top, cement, wood or tile thus completing the total sensory information deprivation of the entire foot. Thus, not only did he take away critical adaptive skills from himself and generations to follow, but he began the deprivation of the brain of critical information from which the central nervous system would need to develop and continue to function effectively. It is not unlikely that the man of pre-shod time had a strong competent foot arch (perhaps somewhat flat to increase surface area contact for adaptation), but one that did not need orthotics, stability shoes or rigid shanks and inserts. In other words, the foot and its lower limb muscles were strong with exceptional skills and endurance. But in today’s day and time things are now different. We now affix a shoe to the child’s foot even before he can walk and then when he does, all propriosensory information necessary for the development of critical spinal and central nervous system reflexes is ensured to be virtually absent. Is it any wonder why there are so many people in chronic pain from postural disorders related to central core weakness and inhibition ? Is it any wonder why so many people seem to have flat incompetent feet and arches? Man has done it to himself, but thankfully man has proven that what he can do, he can undo. Thankfully we see modern medical research that has delved into this realm of thought and has uncovered the woes of our ways and to follow, companies like those mentioned earlier are imagining and developing devices that will allow us some protection from modern day offenses such as glass, plastics and metal and thus allow us the slow and gradual return to our healthier foot days, all fashion sense aside.

 Shawn and Ivo, The Gait Guys

Two fellas that were here at the beginning, and two fellas that will be here for the duration. 

Podcast #29: DARPA Robots & Cartilage in Runners

podcast link: 

http://thegaitguys.libsyn.com/podcast-29-darpa-robots-cartilage-in-runners

iTunes link:

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

Gait Guys online /download store:

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

other web based Gait Guys lectures:

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


Today’s show notes:

1. Neuroscience Piece:
Human or Robot? Harder to Tell In Latest Bipedal Robot PETMAN Video
http://singularityhub.com/2013/04/07/human-or-robot-harder-to-tell-in-latest-bipedal-robot-petman-video/

Boston Dynamics is building the bipedal PETMAN (Protection Ensemble Test Mannequin) for the Defense Advanced Research Projects Agency (DARPA).

_____________
2.BIOWARE
How do we fit into this growing paradigm (bioware) and the bionics paradigm

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3.  http://www.sciencedaily.com/releases/2013/04/130408184727.htm

Human or Robot? Harder to Tell In Latest Bipedal Robot PETMAN Video

In their study published in the American Journal of Physiology: Regulatory, Integrative and Comparative Physiology on April 3, 2013, Roberts and Booth put rats in cages with running wheels and measured how much each rat willingly ran on their wheels during a six-day period. They then bred the top 26 runners with each other and bred the 26 rats that ran the least with each other. They repeated this process through 10 generations and found that the line of running rats chose to run 10 times more than the line of “lazy” rats.

4. Defending Barefoot

http://drnicksrunningblog.com/2013/04/04/experts-defend-barefoot-running-shoes-despite-new-evidence-indicating-the-footwear-could-promote-bone-injury/

5. hunter7979 asked you:

 Hey I have been injured for a long time I was hoping you could give me some insight on how to treat it. Started with ITBS in both knees about two years ago. Somehow my pelvis got thrown out of whack and I ended up with funky gait and scoliosis. I feel like my left leg is shorter, internally rotated and pronating. Supposedly my right leg is actually a tiny bit longer but not enough to make a real difference. Orthotics helped balance out my pelvis but I still walk/run funky. Appreciate it guys
6. Disclaimer

7.  How does your sport change your gait?
Twitter post we did….The Gait Guys (@TheGaitGuys)
4/4/13 1:18 PM
Doing lots of “in the guard” strategizing in jiujitsu last few weeks. Hip flexors are getting punished & inhibiting Glutes and hip extension.
8. Epidemic of Crocs footwear in the fort Meyers airport! No wonder we have so many gait problems. Would like to get @TheGaitGuys opinion!



A Scientific Look at Heeled Shoes. A nice follow up to the Zero Drop trend this week.

This blog post was from a year ago, but seems to be appropriate to follow up our two “zero drop” articles this week. Enjoy

http://well.blogs.nytimes.com/2012/01/25/scientists-look-at-the-dangers-of-high-heels/

Can you think of a better way to start the week than with a discussion of high heels? We all like high heels… Well, at least guys do (and we know quite a few women who do as well…some of you may be reading this post). NO, WE DO NOT LIKE TO WEAR THEM, but we can admire the way they make the calves look so great and the increased lumbar lordosis and accentuation of the greatest gait muscles ever created!

Were they based off “chopines” from the 15th century; an elevated shoe (7-30 inches high!) which kept the peoples feet literally “out of the muck” (they didn’t have modern plumbing back then) or are they older? Or was the heel invented out of necessity to keep horse riders literally “in the saddle” ? Chinese and Turkish history says maybe they were to keep women (particularly concubines) from escaping. For the intents of discussion, we will stick with this last premise, as it fits nicely with the findings of this article (based on the study published here)

Remember the neuromechanics posts on muscle spindles or golgi tendon organs (GTO’s) ? If not, click the links and check them out; suffice it to say that the take home message is: Spindles respond to length and GTO’s respond to tension.

We also remember that GTO;’s modulate the muscles function that they come from. In other words, they literally “turn off” the muscle they come from (it is a disynaptic, post synaptic pathway for you neuro geeks out there). In light of that, lets look at some quotes form the article:

“the scientists found that heel wearers moved with shorter, more forceful strides than the control group, their feet perpetually in a flexed, toes-pointed position. This movement pattern continued even when the women kicked off their heels and walked barefoot. “

No surprises here. Go up on your toes and take a few strides (more difficult for guys, since the biggest heel we may have is about 12mm in our running shoes). Which muscles are engaging? See how difficult it is to take a full stride? Try to engage your glutes. Not so easy, eh? Now put your foot flat on the floor, extend your toes and NOW engage your glutes. Easier? Presyanptic loading of the motor neuron pool pays big dividends!

They go on to say: “As a result, the fibers in their calf muscles had shortened and they put much greater mechanical strain on their calf muscles than the control group did.”

Hmmm… shortened muscles put under greater tension. Sounds like a job for the golgi’s, and what do they do? Inhibit the muscle from contracting. No wonder is was harder.

“In the control group, the women who rarely wore heels, walking primarily involved stretching and stressing their tendons, especially the Achilles tendon. But in the heel wearers, the walking mostly engaged their muscles.”

Wow, here is evidence They changed their motor programming!  Did you ever think that high heels could change the way our brain works? Maybe it’s a secret plot to take over the world….or maybe not…

The Gait Guys…Lovers of high heels as long as you don’t walk in them….

Zero Drop? Think before you drop. More to think about before you make the jump (or run, or walk or stand…)

Ramp Delta. Drop. Heel to toe differential. Stack height differential. You have likely heard all the words before. We are talking about the difference in height between the center of the heel and ball of the big toe on the foot. It is literally “how much heel” the shoe has. Some have upwards of 20mm, some none at all (zero drop). The average seems to be 10-15 mm for many shoes, but that tradition is evolving to less and less (Brooks for example now has the “Pure” Series with a 4 mm average and one shoe that can be either 4 or zero (The Drift)). New Balance has their miniumus, Altra has their army of shoes, Saucony has a variable selection. Everyone is on target with their collection of minimalist or minimalist-trending (or as we like to call them, “gateway”) shoes.

Since we are born “sans” shoes, zero seems “natural” or maybe the best, right? Maybe, maybe not. A lot depends on you and your anatomy however logic dictates that we were born with the rear and forefoot on the same plane so there has to be a natural logic to the zero drop trend. The problem remains, how long have you been forcing this non-natural state and how long (if at all) will you be able to return to the “less is more” trend?

If you have been in shoes with more drop your whole life, your musculoskeletal system and neurology has adapted to that. If we take away our favorite chair, pair of shoes, golf club or whatever, you may have something to say about it. Same for your feet. If you drop/lower your heel, there are biomechanical changes and possible consequences.

You may have read this weeks post, talking about having enough ankle range of motion available. Dropping the heel requires more dorsiflexion (or extension) of the ankle. If that range of motion is not available, then the motion needs to occur somewhere else.

So, where elsewhere in the body is the motion going to occur ? Dropping the ankle requires more knee extension. Do you have that range of motion available? Are your knees painful when you wear a zero drop shoe?

How about your hips? Dropping the heel requires more hip extension as well. This extension is often accompanied by internal rotation of the hip (ankle dorsiflexion, along with foot abduction and forefoot eversion are all components of pronation, which will cause medial rotation of the hip. Do you have this range of motion available, or do you have femoral retro torsion, and a zero drop shoe makes that worse?

What about the effect on the low back? Dropping the heel decreases the lumbar lordosis (the natural curve forward). Don’t believe us ? Just look at any woman in a 3 inch pump and you will see some lovely curves. This places additional stress on the posterior ligaments and joint capsules and compression and shear on the discs. Some spines won’t tolerate this, just like some won’t tolerate heels, which increases the lumbar lordosis and places more stress on the posterior joints.

What about the mid back? Dropping the heel decreases the thoracic curve. How much extension (backward movement) do you have in your mid back?

The same with the neck…and the list goes on….

As you can see, it is much more complex than just changing to a shoe with less drop. Because of the biomechanical changes and demands, it will probably cost you something, be it range of motion, comfort, function. We are not saying it isn’t worth it, or that you shouldn’t do it; we are saying go slow and listen to your body. What may be right for someone else may not be right for you … . either in the short or long term.

Earn your way. Don’t throw caution to the wind. We see people everyday that have suffered the above consequences due to listening to the wonderful marketing of the minimalist trend and from embracing some of the nonsense on the web.  We call these people, “patients”.  Don’t make yourself a patient, use your head when it comes to your feet.

The Gait Guys

Ivo and Shawn

All material copyright 2013 The Gait Guys/ The Homunculus Group. All rights reserved. Please ask before lifting our material.

Podcast #28: Nanotech, Athletes & Barefoot ?


podcast link: 

http://thegaitguys.libsyn.com/podcast-28-nanotechnology-athletes-minimalism

iTunes link:

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

Gait Guys online /download store:

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

other web based Gait Guys lectures:

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


Today’s show notes:

1. Neuroscience Pieces:

Technology is advancing so quickly that it won’t be long before the era of performance-enhancing drugs seems like the athletic Stone Age. Injecting or ingesting chemicals will be considered primitive when athletes will have the ability to have robotic cells powered by software coursing through their veins.

Russian Billionaire Wants to Create Cyborgs for Real

http://mashable.com/2013/04/01/avatar-project/


2.
Barefoot Running Can Cause Injuries, Too

By GRETCHEN REYNOLDS


http://well.blogs.nytimes.com/2013/03/06/barefoot-running-can-cause-injuries-too/
http://www.ncbi.nlm.nih.gov/pubmed/23439417

3. Running with sesamoiditis: How I resolved a 10 year injury by ditching my traditional running shoes. | Dr. Nick’s Running Blog
http://drnicksrunningblog.com/2013/04/04/running-with-sesamoiditis-how-i-resolved-a-10-year-injury-by-ditching-my-traditional-running-shoes/


4. Case
I have a question about peroneus longus in relation to “morton’s toe”. I did a very deep deep massage for an extended length of time and found that when I put my foot on the floor afterwards, the first metatarsal head was no longer raised!! Can you advise what may cause the peroneus longus to become tight, and if there any good stretches for it?
Thank you,Tracy



5. Do orthopedic shoes really help?
http://www.ncbi.nlm.nih.gov/pubmed/23496924

Well, they do seem to assist in foot placement and can enhance proprioception, so in the right circumstances, they can be an excellent adjunct to exercise and rehabilitation.

“Footwear adaptation led to pain relief and to improved foot & ankle proprioception. It is likely that that enhancement allows patients to better control foot placement. As a result, higher dynamic stability has been observed. LDS seems therefore a valuable index that could be used in early evaluation of footwear outcome in clinical settings.”


6. Shoes and Performance. Does it surprise you that it affects adolescents too? It shouldn’t:

http://www.sciencedaily.com/releases/2013/03/130319091420.htm

Midfoot strike in a non-zero drop shoe. Have you thought about this ?

Here is something to think about. As one midfoot strikes the foot during walking or running the individuals body mass is typically directly over the foot.  When this occurs in a zero drop shoe (ie. flat, your rear and forefoot are on the same plane) the tibia-ankle is at the very least, at 90 degrees. Meaning, the tibia is at the very least at 90 degrees and is at the very least perpendicular to the ground and plane that the foot is on.  And with just a little bit of forward body mass movement over the foot the critical and necessary range of 110-115 plus degrees of ankle dorsiflexion (depending on your reference source) is achieved. This means that one does not have to prostitute the foot into greater than normal pronation to drop the arch further to gain the extra amount of ankle rocker (dorsiflexion) that is necessary to pass over the foot.

However, think about this.  What if that same foot is in a stacked heel shoe.  There are plenty of shoes still out there that have a ramp delta that is above zero drop. So, what we have is a shoe that has the heel higher than the forefoot, a sloped shoe.  IF this same foot midfoot strikes what happens now ?

Well, midfoot strike now occurs in a relatively greater plantarflexed posture (ie. heel is raised higher than the forefoot because of the shoe). This means we are not anywhere near the 115 degrees necessary for normal gait, timely heel departure, timely forefoot load, timely hip extension, timely gluteal activation etc. These timely gait events are paramount to normal gait and when they are altered injury and altered tissue loads can occur.  Altered motor recruitment patterns are likely to ensue.  In the scenario proposed, as the body mass moves over the slightly plantarflexed foot we might now only get to 90 degrees of ankle rocker before the body mass is far enough forward to create the passive heel rise during late-midstance phase of gait. And when the body can only get 90 degrees of ankle dorsiflexion/rocker during midstance the extra amount of dorsiflexion range may need to come from some other joint.  It may come from more than normal midfoot pronation, knee hyperextension, knee valgus etc. This is potentially a long list of compensations.

Our point is simple here and at this time it is just a tip of the iceberg article for us.  But we thought we would put this idea out there to share some of the things we think about on a daily basis, and some of the things that get played out in our clinics each and every day. 

Changing your running form involves so much more than just changing your form. If you change to a midfoot or forefoot strike what kinds of biomechanics are you employing ? Do you have the neuromechanics to accompany these running form changes ? Do you have the necessary ranges of motion ? Do you have strength in potential compensation patterns to fend off both subtle and dramatic running form changes ?  If not, you might find out that your initial response is “ I just cannot do a midfoot or forefoot strike running form. I get foot pain, or knee pain, or hip pain.”

Conversely, think about this regarding our postulation above.  If you have been employing a midfoot strike or forefoot strike pattern in stacked heeled shoes and suddenly try a zero drop shoe you better be aware of symptoms such as pain, tightness or other complications.  Is your body able to adapt to a new (possibly increased) ankle-midfoot rocker or the demand of a greater ankle-midfoot with the newly dropped heel? Is your body immediately adaptive enough after going through that stage of gait with the heel higher than the forefoot for years ?  Just because you went to a running form clinic doesn’t mean  you are ready to make that your new form tomorrow. Change takes time, so be patient with your body and let it adapt.

Food for thought, especially for those who say to others. “Hey dude, chuck your ramped shoes and go minimialism or barefoot. Just go for it. I did and I was fine !”

What is fine for one, is not fine for all.

Shawn and Ivo

The Gait Guys

Another IFGEC Certification Granted

&ldquo;With more than 2 decades in the fitness industry, and a MS in Exercise Physiology, I&rsquo;ve learned that there is so little that I really know.  I am constantly looking to improve what I can do to help t…

Another IFGEC Certification Granted

“With more than 2 decades in the fitness industry, and a MS in Exercise Physiology, I’ve learned that there is so little that I really know.  I am constantly looking to improve what I can do to help the triathletes and runners that I see.   As an endurance coach and clinician that focuses on preventing injuries, optimizing performance, and avoiding reoccurring injuries, the IFGEC Shoe Fit Certification is going to be a keystone (much like the Navicular Bone) to my screening process of athletes and clients.  Making sure they are fitted properly in shoes, working with their movement patterns, teaching them running form skills, and then building on all aspects from there.  What I have learned from "The Gait Guys” has already made an impact on what I do, but it’s at a whole new level now.  This is not just a “online course”  this is real education that stays with you for life.  This is a true Ground Up approach to helping and is something that every running shoe store, coach, and medical professional that deals with runners and triathletes needs to learn.“
Ryan Smith, MS is owner of the Personal Impact, LLC and The Runners’ Clinic in the Cincinnati, Ohio area.  He is a USATF Level 1 Coach, Newton Natural Running Form Coach, & ACSM-CPT that works with runners and triathletes helping to prevent and recover from injuries that athletes deal with.  More information on Ryan Smith, visit his site at.  http://ryansmithfitness.com
Want to get certified or learn more? Email us at thegaitguy@gmail.com
tumblr_mkhd6xIXbo1qhko2so1_1280.jpg
tumblr_mkhd6xIXbo1qhko2so2_1280.jpg

Do you think I need to replace my shoes?

These shoes appear to be well past their prime, to say the very least ! These poor dogs have the rear and forefoot varus “worn” right into them. You can see this represented particularly easily from the front, look at the lateral sloping of the shoe. It almost appears as if his foot could slide off the outside edge of the shoe. One can easily postulate that an inversion ankle sprain is just one unfortunate step away.

It looks like this medially posted shoe is not working for this fellow (you can see the medial post on the inner edge of the EVA midsole if you look carefully)  If you have questions on the “flare”?/post click here) . The client told us that they are “only a few years old” and planned on running one more ½ marathon in them this spring! Of course we mentioned they should put a office visit on the books the day after that race, because their ankles and knees were likely going to need it !

One can only imagine the lateral (genu varum) forces being placed on the knees, and who knows what kinds of increased shear forces are imparted into the menisci.  The lateral (inversion / varus) forces are going to impart a tendency of external rotation into the hips, and if one is busy externally rotating they are not going to internally rotate the hips when it is necessary to as the pelvis passes over the foot in midstance.  Additionally, an inverted /varus postured foot is more rigid because it is supinated which makes for a poor pronation/shock absorbing foot during the accomodative phase of the stance phase.

There are many more issues we could discuss here. But this was never meant to turn into a diatribe on specific biomechanical flaws, not this time at least.  Just remember this, whatever biomechanical flaws your feet have (and most of us have them) will eventually be pressed into the EVA foam of your shoes. Meaning, in time your shoes will reflect your aberrant flaws biomechanically.  And these newly built-into-the-shoe problems will now magnify the foot’s challenges and can accelerate pathology locally and globally.  Change your shoes often and as we have suggested in older blog posts, please consider having 2 shoes in your regular rotation.  One shoe being older and one being newer. We suggest starting an new shoe into the rotation once the old shoe has 200-250 miles and then alternating shoes every other day.  This way the foot is never seeing an older more deformed shoe for more than a day before getting some correction.  The point here, don’t let a shoe get 400-500 miles on it, in all its deformed glory, and then suddenly force the foot into a sudden biomechanical correction with a brand new shoe.  Abrupt changes lead to abrupt biomechanical demands on the system, so limit them and limit your risk for injury.

PS: Note the nice after-market “venting feature” in the right shoe near the little toe.

What some folks will try to do to save a few bucks…

Ivo and Shawn, The Gait Guys

Podcast #27: Futuristic Gait & Vertical Oscillations

 Pod #27

podcast link: 

http://thegaitguys.libsyn.com/pod-27-futuristic-gait-vertical-oscillations

iTunes link:

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

Gait Guys online /download store:

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

other web based Gait Guys lectures:

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


Today’s show notes:

1. Neuroscience Piece:

-http://www.designnews.com/author.asp?section_id=1386&itc=dn_analysis_element&doc_id=254901&page_number=1&dfpPParams=ind_182,industry_medical,aid_254901&dfpLayout=blog

Six months after doctors told him he would likely never walk again after a random accident at home, 49-year-old Chris Tagatac was back on his feet and taking steps, a feat that elated not only him, but also his family.

Tagatac didn’t accomplish this feat on his own, however. He was walking with the help of Ekso, a wearable robot from a company called Ekso Bionics that consists of braces, sensors, and motors that anticipate people’s movements and take steps for them.


2- NEURO 2
http://reuters.tumblr.com/post/46251254817/for-the-first-time-scientists-have-printed-human


For the first time scientists have printed human embryonic stem cells using a 3D printer

The Heriot-Watt University team’s research could eventually lead to human organs being printed on demand and an end to animal drug testing. Jim Drury reports.

 

3. Vertical Oscilations, Danny Abshire and Running & Walking

https://www.facebook.com/photo.php?v=575995729092248&set=vb.111772995514526&type=2&theater

This study’s findings findings clearly demonstrate that human walkers consume substantially more metabolic energy when they minimize vertical motion.

Anyhow, the summary of this peer reviewed article by Ortega concluded that :

“in flat-trajectory walking, subjects reduced center of mass vertical displacement by an average of 69% but consumed approximately twice as much metabolic energy over a range of speeds . In flat-trajectory walking, passive pendulum-like mechanical energy exchange provided only a small portion of the energy required to accelerate the center of mass because gravitational potential energy fluctuated minimally. Thus, despite the smaller vertical movements in flat-trajectory walking, the net external mechanical work needed to move the center of mass was similar in both types of walking. Subjects walked with more flexed stance limbs in flat-trajectory walking, and the resultant increase in stance limb force generation likely helped cause the doubling in metabolic cost compared with normal walking. Regardless of the cause, these findings clearly demonstrate that human walkers consume substantially more metabolic energy when they minimize vertical motion.”

J Appl Physiol. 2005 Dec;99(6):2099-107. Epub 2005 Jul 28. Minimizing center of mass vertical movement increases metabolic cost in walking. Ortega JD, Farley CT. Source



J Sports Sci. 2005 Jul;23(7):757-64.

Effect of a global alteration of running technique on kinematics and economy.



J Biomech. 2011 Apr 7;44(6):1104-7. doi: 10.1016/j.jbiomech.2011.01.
028. Epub 2011 Feb 20.

Changes in running mechanics and spring-mass behavior induced by a mountain ultra-marathon race.


http://www.technologyreview.com/view/413593/revealing-the-secrets-of-human-gait/

Revealing the secrets of human gait

A simple measure of the forces involved in walking may help diagnose and treat injuries and arthritis

So the work of Yifang Fan and pals at Jinan University in China is a refreshing step forward (so to speak). Fan and co say they have discovered an independent measure of gait which they call the vertical gait reaction force. This is a measure of the amount by which a person’s centre of gravity raises during two complete steps (with the left and then the right foot).

In healthy adults, and Fan and co have tested 173, this force is symmetrical with regard to left and right foot, a finding they call the principle of least action (in other words, the body does no more than it has to move you around). That’s useful, they say, because no other measure gives this kind of symmetric signal for all healthy people.

In adults carrying an ankle injury or with arthritis, the pattern of force is not symmetrical. That allows a quick diagnosis simply by measuring this force and may in future point to the type of rehabilitation that may treat the condition.

_____________
4. Shoe: NB minimus (the new one) and the HI-REZ

http://www.newbalance.com/Minimus-Hi-Rez-Where-Science-Meets-Design/article_minimus_hirez_where_science_meets_design,default,pg.html___________________

 Shawn and Ivo, The Gait Guys

 

More on the Great Debate: Does decreased step height (resulting in less vertical oscillation) increase running economy

There continues to be a plethora of conflicting data out there on the web. Yes, shocking realization !

This study looks at 16 triathletes; 8 folks trained in the “pose method” of running for 12 weeks, versus the 8 folks who just kept running in their usual fashion (ie. the control group perhaps also known as the “beer and Doritos group"  : )  ). They measured changes in stride length (decreased in posers), vertical oscillation (decreased in posers) and oxygen cost (increased in posers).

According to the study’s conclusion

"The global change in running mechanics associated with 12 weeks of instruction in the pose method resulted in a decrease in stride length, a reduced vertical oscillation in comparison with the control group and a decrease of running economy in triathletes”

Why the changes? Perhaps it takes longer to train appropriately in this method and to become efficient at the method. Perhaps when you lose the “pendulum effect” we spoke about last Thursday on the blog, you become less efficient, or maybe there is another factor. MAYBE “pose running” just isn’t more efficient. Time and more studies will tell.

The Gait Guys. Telling it like it is and bringing you the meat….without the filler

all material copyright 2013 The Gait Guys/ The Homunculus Group. Please ask before lifting our stuff.

J Sports Sci. 2005 Jul;23(7):757-64.

Effect of a global alteration of running technique on kinematics and economy.

Source

Department of Exercise Science, Health Promotion and Recreation, Colorado State University - Pueblo, Pueblo, CO, USA. george.dallam@colostate-pueblo.edu

Abstract

In this study, we examined the consequences of a global alteration in running technique on running kinematics and running economy in triathletes. Sixteen sub-elite triathletes were pre and post tested for running economy and running kinematics at 215 and 250 m.min-1. The members of the treatment group (n=8) were exposed to 12 weeks of instruction in the “pose method” of running, while the members of the control group (n=8) maintained their usual running technique. After the treatment period, the experimental group demonstrated a significant decrease in mean stride length (from 137.25+/-7.63 cm to 129.19+/-7.43 cm; P<0.05), a post-treatment difference in vertical oscillation compared with the control group (6.92+/-1.00 vs. 8.44+/-1.00 cm; P<0.05) and a mean increase in submaximal absolute oxygen cost (from 3.28+/-0.36 l.min-1 to 3.53+/-0.43 l.min-1; P<0.01). The control group exhibited no significant changes in either running kinematics or oxygen cost. The global change in running mechanics associated with 12 weeks of instruction in the pose method resulted in a decrease in stride length, a reduced vertical oscillation in comparison with the control group and a decrease of running economy in triathletes.

PMID:16195026 [PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov/pubmed/16195026

The Importance of Stupidity in Scientific Research: aka.... "How The Gait Guys feel much of the time"

We started The Gait Guys in some ways because despite all of the questions we asked  over the years,  from those who we all deemed as “those who are supposed to know”, we rarely got answers that we felt were sufficient for our thirst.

We had the research data that everyone else had, but no one was helping us put together a big picture that made sense or had reasonable clinical outcomes.  We are on a journey here at The Gait Guys. A journey based on the honesty and truth behind how the human body ambulates, the parameters that are necessary for it to work right, and what happens when things go wrong.

In the mean time, we share the conclusion statement of this journal article (link) .  It pretty much sums up how Ivo and I feel from time to time.  We hope you enjoy the reality of the statement.

____________________________________________

Productive stupidity means being ignorant by choice. Focusing on important questions puts us in the awkward position of being ignorant. One of the beautiful things about science is that it allows us to bumble along, getting it wrong time after time, and feel perfectly fine as long as we learn something each time. No doubt, this can be difficult for students who are accustomed to getting the answers right. No doubt, reasonable levels of confidence and emotional resilience help, but I think scientific education might do more to ease what is a very big transition: from learning what other people once discovered to making your own discoveries. The more comfortable we become with being stupid, the deeper we will wade into the unknown and the more likely we are to make big discoveries.” -Martin A. Schwartz

________________________________________________________

The key to the statement above was …. ” as long as we learn something each time”.  Otherwise, according to Einstein, we would be considered insane. 

Technology and medicine are moving at light speed our dear brethren. This is why we start our weekly podcast (LINK) with a neuroscience piece and link the new science and technology discoveries to gait and human movement. Because we would all be stupid not to look forward under the exponential growth paradigm that is today’s reality.

Have a good week everyone…….we have some great stuff queued up for the week, hope you get a little out of it all.

- We remain……..The Gait Guys……two “productively and comfortably stupid” gentlemen.

Vertical Oscilations, Danny Abshire and Running & Walking

https://www.facebook.com/photo.php?v=575995729092248&set=vb.111772995514526&type=2&theater

We saw this short 1 minute video by Danny Abshire on vertical movements in running (link is above). Here was the caption placed (by Runner’s Soul) with the video.

  • “Danny Abshire, running guru and CTO of Newton Running, explains how vertical oscillation can impede any runner’s performance - did you know that lifting 6 inches with every foot strike can add almost 2.5 miles onto a marathon?”
We are currently trying to find the reference material he used (anyone please forward it to us at thegaitguys@gmail.com).  In theory it makes sense.  Here is an article that shows something a little different. This research article shows shows that minimizing the center of mass vertical movement increases metabolic cost because of the loss of passive mechanical energy from pendulum mechanics. Now, to be fair, apparently Danny was talking about increased distance and not metabolic cost. But what if distance was trumped by energy and time ?  Now there is a neat thought ! We doubt any marathoner would be upset if they ran further than the actual marathon distance but PR’d in the attempt.  One could easily postulate that the term “increased metabolic cost” would mean a slower run time because of the activity being inefficient.
  • This study’s findings findings clearly demonstrate that human walkers consume substantially more metabolic energy when they minimize vertical motion.

In this study’s case, it refers to walking, however could it postulate to running as well?  Just something to think about.  As our reading on this topic continues, and as we find supportive and conflicting journal information we will post attachments here amongst our other articles to make sure our readership can see both sides of the peer reviewed research. In Danny’s, and everyone defense, we often find conflicting research in peer reviewed articles, it almost seems at though one can take a stance on any side of a medical topic and find an article to prove the theory, sadly often leaving us nowhere but spinning in place.

Anyhow, the summary of this peer reviewed article by Ortega concluded that :

“in flat-trajectory walking, subjects reduced center of mass vertical displacement by an average of 69% but consumed approximately twice as much metabolic energy over a range of speeds . In flat-trajectory walking, passive pendulum-like mechanical energy exchange provided only a small portion of the energy required to accelerate the center of mass because gravitational potential energy fluctuated minimally. Thus, despite the smaller vertical movements in flat-trajectory walking, the net external mechanical work needed to move the center of mass was similar in both types of walking. Subjects walked with more flexed stance limbs in flat-trajectory walking, and the resultant increase in stance limb force generation likely helped cause the doubling in metabolic cost compared with normal walking. Regardless of the cause, these findings clearly demonstrate that human walkers consume substantially more metabolic energy when they minimize vertical motion.”

In our summarizing of the article it indicated that more vertical motion seems to engage some of the energy conserving pendulum effects of the limbs. We know this happens in the spine. Serge Gracovetsky (“the Spinal Engine”) and many other researchers have discussed this energy conservation by the repetitive coiling and uncoiling of the spinal curves and loading/unloading of the spinal discs.   Here is the journal and abstract below.

Shawn and Ivo, The Gait Guys

________________________________

J Appl Physiol. 2005 Dec;99(6):2099-107. Epub 2005 Jul 28. Minimizing center of mass vertical movement increases metabolic cost in walking. Ortega JD, Farley CT. Source

Locomotion Laboratory, Dept. of Integrative Physiology, University of Colorado, Boulder, CO 80309-0354, USA. ortegajd@colorado.edu

Abstract

A human walker vaults up and over each stance limb like an inverted pendulum. This similarity suggests that the vertical motion of a walker’s center of mass reduces metabolic cost by providing a mechanism for pendulum-like mechanical energy exchange. Alternatively, some researchers have hypothesized that minimizing vertical movements of the center of mass during walking minimizes the metabolic cost, and this view remains prevalent in clinical gait analysis. We examined the relationship between vertical movement and metabolic cost by having human subjects walk normally and with minimal center of mass vertical movement (“flat-trajectory walking”). In flat-trajectory walking, subjects reduced center of mass vertical displacement by an average of 69% (P = 0.0001) but consumed approximately twice as much metabolic energy over a range of speeds (0.7-1.8 m/s) (P = 0.0001). In flat-trajectory walking, passive pendulum-like mechanical energy exchange provided only a small portion of the energy required to accelerate the center of mass because gravitational potential energy fluctuated minimally. Thus, despite the smaller vertical movements in flat-trajectory walking, the net external mechanical work needed to move the center of mass was similar in both types of walking (P = 0.73). Subjects walked with more flexed stance limbs in flat-trajectory walking (P < 0.001), and the resultant increase in stance limb force generation likely helped cause the doubling in metabolic cost compared with normal walking. Regardless of the cause, these findings clearly demonstrate that human walkers consume substantially more metabolic energy when they minimize vertical motion.

Ankle muscle spindles play a significant role in the control of posture and balance during the swing phase of locomotion

 
                                                                                                              
“The results provide strong evidence that the primary endings of ankle muscle spindles play a significant role in the control of posture and balance during the swing phase of locomotion by providing information describing the movement of the body’s COM with respect to the support foot. Our results also provide supporting evidence for the proposal that there are context-dependent changes in muscle spindle sensitivity during human locomotion."                                                                                    

  • This study tells us what we already know: The muscles surrounding the ankle, especially of the leg you are standing on (the "stance” phase leg) provide important information to the central nervous system about both that leg AND the leg not on the ground (The “swing” phase leg).  Remember the central integration of things like the Crossed Extensor Response we have talked about in prior podcasts ?
  • The implications are that if you have an ankle injury, this mechanism can be altered, resulting in loss of balance (or proprioception) as well as opening you up to greater (or additional) injury.
  • The other implication is that the whole ball of wax is “situationally dependent”; meaning plastic and adaptable. Pretty cool !
The Gait Guys. Bringing you the latest and greatest, each and every post.
                                                                                       
                                                                                                                
 SOURCE:
Exp Brain Res. 2002 Mar;143(1):24-34. Epub 2001 Dec 18.

The effects of human ankle muscle vibration on posture and balance during adaptive locomotion.

Source

Gait and Posture Laboratory, Department of Kinesiology, University of Waterloo, Ontario N2L 3G1, Canada.

Abstract

This study investigated the contribution of ankle muscle proprioception to the control of dynamic stability and lower limb kinematics during adaptive locomotion, by using mechanical vibration to alter the muscle spindle output of individuals’ stance limbs. It was hypothesised that muscle length information from the ankle of the stance limb provides information describing location as well as acceleration of the centre of mass (COM) with respect to the support foot during the swing phase of locomotion. Our prediction, based on this hypothesis was that ankle muscle vibration would cause changes to the position and acceleration of the COM and/or compensatory postural responses. Vibrators were attached to both the stance limb ankle plantarflexors (at the Achilles tendon) and the opposing dorsiflexor muscle group (over tibialis anterior). Participants were required to walk along a 9-m travel path and step over any obstacles placed in their way. There were three task conditions: (1) an obstacle (15 cm in height) was positioned at the midpoint of the walkway prior to the start of the trial, (2) the same obstacle was triggered to appear unexpectedly one step in front of the participant at the walkway midpoint and (3) the subjects’ walking path remained clear. The participants’ starting position was manipulated so that the first step over the obstacle (when present) was always performed with their right leg. For each obstacle condition participants experienced the following vibration conditions: no vibration, vibration of the left leg calf muscles or vibration of the anterior compartment muscles of the lower left leg. Vibration began one step before the obstacle at left leg heel contact and continued for 1 s. Vibrating the ankle muscles of the stance limb during the step over an obstacle resulted in significant changes to COM behaviour [measured as displacement, acceleration and position with respect to the centre of pressure (COP)] in both the medial/lateral (M/L) and anterior/posterior planes. There were also significant task-specific changes in stepping behaviour associated with COM control (measured as peak M/L acceleration, M/L foot displacement and COP position under the stance foot during the step over the obstacle). The results provide strong evidence that the primary endings of ankle muscle spindles play a significant role in the control of posture and balance during the swing phase of locomotion by providing information describing the movement of the body’s COM with respect to the support foot. Our results also provide supporting evidence for the proposal that there are context-dependent changes in muscle spindle sensitivity during human locomotion.

Mobium, Schmobium.

Here is the latest and greatest from the shoe manufacturer, Puma; it is their version of a more “adaptive” or “accommodative” shoe. They do not say minimalisitic, but rather it interferes minimally with walking or running. Good thing, because it has a pretty thick sole, superimposes a pretty substantial arch to the foot, and also has a fairly narrow toe box. Their runner is also a heel striker, at least at the beginning of the video.


Last time we checked, the plantar fascia was not “X” shaped and was present on the entire plantar surface of the foot, without an “apex” or “torque” in the center of where the medial longitudinal arch is located.

In referring to mirroring as they do in the video, we were wondering which muscles, bones and fat pads of the foot the “pods” actually mirror? And then there is those siping lines of the outsole, what’s with them and their location? The metatarsal heads form an arc at their distal end, where they articulate with the phalanges, as do the interphalageal joints (joints between the toes). This shoe’s lines arc less than we would expect.

They have the 5 metatarsal pads, not unlike the Newton. What happened at the toes?  Individuals with 3 toes should do well with those pods for the proximal and distal phalanges, but we think this is probably a limited market (wink, smile, wink).

We agree that “expansion” of a shoe is important so we think this shoe has a neat underlying idea. We would hope most folks aren’t wearing shoes that are too tight or short that their feet don’t have room to move inside the shoe.  We are also curious about the height of the lateral longitudinal arch, last time we looked there was not a tunnel shaped arch running under the foot.  The lateral longitudinal arch is always must more subtle and gentle.

Technically sound? We don’t think so, not from what we have discussed above. As for bringing something to the market that doesn’t exist that enhances the performance of the athlete? Well, it is unique, but performance enhancement remains to be seen. As for wrapping the shoe in a blanket of fabulous Puma design? It does have catchy colors and a great marketing campaign…

Just some off the cuff thoughts on our part. We would love a pair to dialogue out these thoughts and others. We are always open to being wrong, but we know our shoes and we know foot and shoe anatomy and biomechanics.  If you are from PUMA, contact us and send us a pair, we will be happy to eat our words if we are wrong in our cursory suppositions.

The Gait Guys. Helping you to make better footwear decisions and ask the questions no one wants to ask

all material copyright 2013 the Homunculus Group/ The Gait Guys. Please ask before using our material.

Podcast #26: Google shoes, shoe tech & indoor track biomechanics

Pod #26: The new Google Shoes, hamstring injuries in short track running and shoe tech.

podcast link: 

http://thegaitguys.libsyn.com/podcast-26-google-shoes-shoe-tech-indoor-track-biomechanics-and-injuries

iTunes link:

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

Gait Guys online /download store:

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

other web based Gait Guys lectures:

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


Today’s show notes:

Two neuroscience pieces today which parlay nicely into last weeks podcast on kurzweils singujlarity

1- Google Shoes

http://www.huffingtonpost.com/2013/03/11/google-shoes_n_2853098.html

http://youtu.be/VcaSwxbRkcE

This weekend, at the annual South by Southwest conference in Austin, Texas, Google unveiled an early prototype of motion-sensing “smart shoes,” with an embedded speaker on the tongue of the shoe that can yell motivation at you when you’re being lazy, or encourage you when you’re being active. Google –which created the talking shoes in collaboration with Adidas,

2- The First Wireless, Implantable Brain-Computer Interface

http://gizmodo.com/5988342/the-first-wireless-implantable-brain+computer-interface-will-help-us-move-things-with-our-minds-on-the-go

3- Problems with small track counterclockwise running

J Mot Behav. 2012;44(1):63-8. doi: 10.1080/00222895.2011.645912. Epub 2012 Jan 13. Asymmetrical neural adaptation in lower leg muscles as a consequence of stereotypical motor training. Ogawa T, Kawashima N, Suzuki S, Nakazawa K.

Clin J Sport Med. 2000 Oct;10(4):245-50. Asymmetrical strength changes and injuries in athletes training on a small radius curve indoor track. Beukeboom C, Birmingham TB, Forwell L, Ohrling D.
4- Puma mobium shoe
http://youtu.be/9cOPMG-TDqw

5- from a Facebook readerI just saw you’re video on hammer toe stretching on tumblr. Great article with it too.
I’ve noticed that on my left foot, my 5th toe doesn’t touch the ground at all when my foot is flat on the ground. It appears not to be doing any work and the pain under the head of my 5th met is getting worse each week now.

6- another facebook question

  • I’ve been doing your shuffle steps and moonwalk to increase my very inflexible ankles. Is there anything else I can do? I read the study and your blog post how stretching doesn’t work. My teammates have literally over twice the dorsiflexion I have and it really shows in my skating. If these two excersises are all that can be done what are the reps/sets/times per week recommendations?

7- Cushioned Heel Running Shoes May Alter Adolescent Biomechanics, Performance
http://www.sciencedaily.com/releases/2013/03/130319091420.htm

Shawn and Ivo

the gait guys

A blast from the past. Here’s one of our favorite posts, just in case you missed us a few years ago…

More Gait Guy Gait Gaffs: What it would look like if “The Flash”, ran with heel strike ? click here. Note the excellent anterior compartment use (nice ankle dorsiflexion and toe extension at terminal swing/ pre-impact) but heavy, nasty, heel strike. What is interesting here is that he has adopted a nice forward lean (ala. natural or chi running style) but when combining this with a heel strike gait you end up with an anterior pelvic tilt (which begins inhibition of the lower abdominals) and you then have to begin the power through phase in early-mid stance phase with the hamstrings. You need tremendous lower abdominal strength, and hamstring length and strength to run this way (go ahead, get up and try it running through your office ! let out a great “Yaulp” from the ensuing hamstring pull (ala Robin Willliams in Dead Poets Society) when you find out your abdominals are not strong enough to lean that far forward and still heel strike, without enough hamstring length (on second thought, just trust  us……although i know now we have challenged some of you). This is a medical disclaimer, dont do it !