The Naked Foot: The Soft Neurology behind Barefoot.

The Naked Foot: Thoughts for the Shoe Minimalist

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 !

_____________________

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  The remainder of this article has been unedited, hence its tense and outdated verbiage, shoe types and research.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.  

Our friend Mountain and his new minimalist dress shoes.

Great job pal !

Barefoot Shoes: ThePrimalProfessional.com 
Facebook: facebook.com/thePrimalProfessional

Primal Professional Shoes | Barefoot Dress Shoes
Fake Heel. Real Style. Real Comfort.

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 !

_____________________

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

_______
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!


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

Podcast #25: Bionics, Arm Swing & Footwear

Great podcast today, #25. Wide range of topics today: the first truly bionic body part, technical shoe issues, GTO’s and more. 

podcast link: 

http://thegaitguys.libsyn.com/podcast-25-bionics-arm-swing-footwear

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

Today’s show notes:

 

1. The First Truly Bionic Hand

http://www.independent.co.uk/life-style/gadgets-and-tech/news/a-sensational-breakthrough-the-first-bionic-hand-that-can-feel-8498622.html

“The first bionic hand that allows an amputee to feel what they are touching will be transplanted later this year in a pioneering operation that could introduce a new generation of artificial limbs with sensory perception.

2. Effects of toning shoes on lower extremity gait biomechanics

http://www.clinbiomech.com/article/S0268-0033%2813%2900010-7/abstract

Clinical Biomechanics, Jan 2013

3. Beware of trendy barefoot running shoes – you could end up with broken bones in your foot

http://www.dailymail.co.uk/health/article-2289725/Beware-trendy-barefoot-running-shoes—end-broken-bones-foot.html?ito=feeds-newsxml

  • Advocates of barefoot running claim it can reduce injuries and back pain
  • ‘Minimalist’ shoes such as these now account for 15% of sales
  • But experts say many people suffer injuries by overdoing it early on
  • Runners should make transition from regular trainers more slowly, they say

4. Foot strike and injury rates in endurance runners: a retrospective study.

Daoud AI, Geissler GJ, Wang F, Saretsky J, Daoud YA, Lieberman DE.
Med Sci Sports Exerc. 2012 Jul;44(7):1325-34. doi: 10.1249/MSS.0b013e3182465115.

Department of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.

5. Effects of foot strike on low back posture, shock attenuation, and comfort in running.

http://www.ncbi.nlm.nih.gov/m/pubmed/23073217/
Med Sci Sports Exerc. 2013 Mar;45(3):490-6

CONCLUSION: Change in foot strike from RFS to FFS decreased overall ROM in the lumbar spine but did not make a difference in flexion or extension in which the lumbar spine is positioned. Shock attenuation was greater in RFS. RFS was perceived a more comfortable running pattern.

*it seems to becoming a question as to what you are doing with the body parts at impact……..where it be you are RFS or FFS.  Do you have the ability to protect the parts in varying mechanical stressful positions.

6. Hey guys, Dr. Ryan:

I just listened to Pod 23 and Ivo you mentioned sagittal curves not developing until after birth..  There is evidence they begin to develop in-utero.  Here is an article excerpt and link to it.
 
“In many anatomy texts, it is often claimed and/or assumed that the cervical lordosis is a secondary curve and is not present during intra-uterine life. However, as early as 1977, Bagnall et al3 demonstrated that the cervical lordotic curve is formed in intrauterine life (9.5 weeks). In 195 fetuses, Bagnall et al3 found that by 9.5 weeks, 83% of fetuses have a cervical lordosis, 11% have a military configuration, and only 6% of fetuses are in the typically described kyphotic position of the cervical spine. This means that by 9.5 weeks, 94% of the fetuses are starting to use their posterior cervical muscles to pull the cervical curve away from the fetal “C”-shape. Fetuses have a cervical lordosis before birth, however, the lordosis increases during post-natal life at ages 3 months-9 months as the infant raises his/her head and begins to sit up.4”

REFERENCES

  1. Harrison DD, et al. Spine 1996; 21: 667-675.
  2. Harrison DD, et al. Spine 2004; 29:2485-2492.
  3. Bagnall KM, et al. J Anat 1977;124:791-802.
  4. Kure S. J Tokyo Med Collage 1972;30;453-470.
  5. Kasai T, et al. Growth. Spine 1996;21:2067-2073.
  6. Harrison DE, Harrson DD, Haas JW. Evanston, WY: Harrison CBP Seminars, Inc., 2002, ISBN 0-9721314-0-X.
  7. Shatz A, et al. Acta Anat 1994;149:141-145.
  8. McAviney J, et al. J Manipulative Physiol Ther 2005;28:187-193.
  9. Bastecki A, et al. ADHD: A CBP Case Study. J Manipulative Physiol Ther 2004; 27(8):e14.


7. “Dynamic Arm Swing in Human Walking, (http://www.ncbi.nlm.nih.gov/pubmed/19640879) where it was determined that normal arm swinging required minimal shoulder torque, while volitionally holding the arms still required 12% more metabolic energy. Among measures of gait mechanics, vertical ground reaction moment was most affected by arm swinging and increased by 63% without it.
* brings up issues of shoulder pathology……rot cuff, frozen shoulder, carrying a purse, water bottle etc


8. Winter foot wear:
We like Steger Mukluks…….youtube video   “gait guys mukluks”

9. Versions: one of the more difficult concepts to grasp…………..here is a Q from a FB reader

  • Does retroversion mean this child will automatically grow up with abnormal mechanics – leading to possible knee foot hip back issue etc? Is there a fix to prevent such without an ortho’s bone saw?
     
    10. The role of GTO’s in plyometric exercises.

Though you weigh less when naked, it doesn’t mean you are more efficient…

“Running barefoot offers no metabolic advantage over running in lightweight, cushioned shoes.”

This study looked at VO2 max (ie. the bodies ability to utilize oxygen, or more precisely, the maximal oxygen uptake or the maximum volume of oxygen that can be utilized in one minute during maximal or exhaustive exercise. It is measured as milliliters of oxygen used in one minute per kilogram of body weight ).

The study found that VO2 increased as weight was added to the foot, whether or not ehy were wearing shoes AND there was not significant difference.

“V˙O(2) increased by approximately 1% for each 100 g added per foot, whether barefoot or shod (P < 0.001). However, barefoot and shod running did not significantly differ in V˙O(2) or metabolic power. A consequence of these two findings was that for footwear conditions of equal mass, shod running had ∼3%-4% lower V˙O(2) and metabolic power demand than barefoot running (P < 0.05).”

An interesting finding was that VO2 was actually 3-4% less for shod running than barefoot, indicating increased metabolic efficiency (albeit small) for shoes.

Why? Our theory is increased biomechanical efficiency with shoes. Shoes, creating less pronatory force and accessory motion (due to cushioning and constraints of the shoe; ie it takes some of the complexity out of the motion) created a more rigid lever with better force transduction.

The Gait Guys. Asking the hard questions and giving you the facts with each post.       


Med Sci Sports Exerc. 2012 Aug;44(8):1519-25. doi: 10.1249/MSS.0b013e3182514a88.

Metabolic cost of running barefoot versus shod: is lighter better?

Source

Locomotion Lab, Department of Integrative Physiology, University of Colorado, Boulder, CO, USA. jason.franz@colorado.edu

Abstract

PURPOSE:

Based on mass alone, one might intuit that running barefoot would exact a lower metabolic cost than running in shoes. Numerous studies have shown that adding mass to shoes increases submaximal oxygen uptake (V˙O(2)) by approximately 1% per 100 g per shoe. However, only two of the seven studies on the topic have found a statistically significant difference in V˙O(2) between barefoot and shod running. The lack of difference found in these studies suggests that factors other than shoe mass (e.g., barefoot running experience, foot strike pattern, shoe construction) may play important roles in determining the metabolic cost of barefoot versus shod running. Our goal was to quantify the metabolic effects of adding mass to the feet and compare oxygen uptake and metabolic power during barefoot versus shod running while controlling for barefoot running experience, foot strike pattern, and footwear.

METHODS:

Twelve males with substantial barefoot running experience ran at 3.35 m·s with a midfoot strike pattern on a motorized treadmill, both barefoot and in lightweight cushioned shoes (∼150 g per shoe). In additional trials, we attached small lead strips to each foot/shoe (∼150, ∼300, and ∼450 g). For each condition, we measured the subjects’ rates of oxygen consumption and carbon dioxide production and calculated metabolic power.

RESULTS:

V˙O(2) increased by approximately 1% for each 100 g added per foot, whether barefoot or shod (P < 0.001). However, barefoot and shod running did not significantly differ in V˙O(2) or metabolic power. A consequence of these two findings was that for footwear conditions of equal mass, shod running had ∼3%-4% lower V˙O(2) and metabolic power demand than barefoot running (P < 0.05).

CONCLUSIONS:

Running barefoot offers no metabolic advantage over running in lightweight, cushioned shoes.

PMID: 22367745
http://www.ncbi.nlm.nih.gov/pubmed/22367745

all material copyright 2013 The Gait Guys/The Homunculus Group.