I am assuming that you have all seen the claims made many times in the barefoot running books, You Tube video’s, blogs and forum posts that barefoot running can increase the height of the arch of the foot due to an increase in muscle strength. Yet you never see any evidence quoted to support the claims as there is none. There certainly are testimonials and the occasional before and after photo posted of an increase in arch height¹ (not to mention just how easy it is to fake pose those photos).
There is no evidence that barefoot running or minimalism leads to an increase in the height of the arch of the foot. I am not denying the testimonials from some barefoot runners that it does happen, but testimonials are just anecdotes and anecdotes are not data or evidence. I have also seen (but unfortunately did not bookmark) a couple of forum posts from barefoot runners commenting that they were disappointed that their arch height did not increase with the barefoot running. This means one set of anecdotes can cancel out another set of anecdotes, which is why we need evidence.
I have never brought into the wishful thinking from so many barefoot bloggers that an increase in the intrinsic muscle strength affects the height of the arch for a number of reasons:
- There is one study that has shown that there is no relationship between muscle power and arch height; another study showing that exercises to increase the strength of those muscles did not affect arch height; however another unpublished abstract reported a decrease in arch height with intrinsic muscles exercises! The evidence certainly does not support the contention that strengthening the intrinsic muscles of the foot leads to an increase in arch height.
- One small study (only 5 subjects) that was presented at the 2011 ACSM meeting showed no change in arch height after 6 months of minimalist running (abstract here). The study has not been published in full for proper peer review and appraisal.
- When you look at the size of those muscles on anatomical dissection, they are extremely small. How can muscles that small have any impact on the height of the arch of the foot?
- We have this abstract from the 2012 ACSM meeting that showed that: “barefoot running does not result in greater activation in these muscles compared to running shod. This suggests that barefoot running may not result in strengthening of the foot intrinsic muscles“.
- If the intrinsic muscles are to increase the height of the arch, they do so by plantarflexing the metatarsals. These muscles run pretty close to parallel with the metatarsal, so have a very poor lever arm to plantarflex them. So how can those tiny muscles with a really poor lever arm come close to doing that, especially against body weight and the magnitude of forces generated during gait?
- The EMG studies on flatfoot show that the intrinsic muscles are very active, much more active than in a ‘normal’ arched foot. While I am the first to acknowledge that EMG does not equal muscle strength, but certainly would ask if they are more active in a flat foot, then they must be stronger than in a ‘normal’ arched foot where they are less active.
- We also know from neurological situations that the opposite can happen. In the diabetic foot when there is an atrophy of the intrinsic muscles (the ‘intrinsic minus foot’) and in very early CMT when only the intrinsic muscles are affected, they tend to actually develop a high arched foot. This suggests that a weakening to the intrinsic msucles of the foot lead to a higher arch structure.
So I would suggest it really is wishful thinking that barefoot or minimalism increases the height of the arch of the foot via the mechanism of increasing strength of the intrinsic muscles of the foot. The evidence and the points raised above do not support that contention.
So what might account for the increase in arch height that some barefoot runners report (and document with photographs)?
Follow this thought experiment:
- When the rearfoot pronates or everts, the medial side of the forefoot can not go through the ground, so the forefoot supinates or inverts relative to the rearfoot to stay flat on the ground. It is this supinated or inverted position of the forefoot on the rearfoot when the rearfoot is pronated or everted that leads to the lowering of the medial longitudinal arch.
- Over a period of time, the soft tissues adapt to the position, so that when you place the rearfoot back into a vertical or neutral position, the forefoot is going to be in an inverted position relative to the rearfoot due to the soft tissue contracture. Those who are familiar with the theoretical constructs will know that what I am describing is a forefoot supinatus (as opposed to the osseous version of a similar looking foot of forefoot varus). Do not try and do this test of keeping the rearfoot vertical yourself to see where the forefoot is as its deceptive due to the tibialis anterior muscle firing and dorsiflexing the medial column of the foot.
- Lets assume someone with this forefoot supinatus transitions to barefoot running or minimalism. The posterior tibial muscle works harder due to the forefoot or midfoot strike pattern and this will invert or supinate the rearfoot more when running.
- More rearfoot inversion means that the medial column of the forefoot/first ray is going to plantarflex more, so over a period of time the soft tissue contracture of the inverted forefoot on the rearfoot will stretch out and the medial longitudinal arch will take on a higher arch profile.
This would easily account for the increase in arch height anecdotally reported by many barefoot runners and has nothing to do with the strength of the intrinsic muscles of the foot. It would also account for those who do not get an increase in arch height, in that they possibly never had the soft tissue contracture of a forefoot supinatus in the first place (maybe they had the osseous version of forefoot varus that no amount of minimalism or muscle strengthening can overcome). Also, this plantarflexion of the first ray will enhance windlass function of the foot, which also affects arch height. I am also going to take a guess and speculate that this may be what Test#3 that I had no idea was about if you are ready to make the transition to minimalism may have something to do with – those with a very high force pronating the rearfoot and causing the forefoot supinatus would probably fail this test and they also are probably not going to be able to make the transition to minimalism. They would fail the test, not because of the rationale that was proposed as being behind the test, but because of the soft tissue contracture of the forefoot supinatus.
This mechanism would also account for any therapeutic benefits and increase in arch height from the foot strengthening woo being marketed by Barefoot Science.
I like to model and do thought experiments, as long as they are consistent with the evidence. As always, I go where the evidence takes me until convinced otherwise
POSTSCRIPT: A study present at the 2013 ACSM mtg that reported the results of 39 runners after a transition to minimalist running shoes. They found no change in arch height (more).
1. I just did a search to find some of these but could not find them. I have seen several and did not bookmark them. If anyone has a link, please contact me as I would like to link to at least one of the before and after photos.
http://videofitness.com/~vfwnk/forum/showthread.php?t=179065
sciencelady:
“Huh… I’ve had a history of plantar facsciitis. I bought barefoot shoes about a year ago and have been using them for weight lifting, kettlebells, and body weight conditioning drills, including some jumping/plyo work. My feet have never felt better – not a speck of arch pain . However, I’ve noticed my arches are flatter than ever . No pain, no issues in the feet, but I can feel the inside of my arch on the floor when I walk barefoot. My ability to stand on my tippytoes is pretty limited, but something I do work on.”
She wore Merrell Pace Glove
Barefoot running does not in any way make the foot (soft tissue structures) stronger. What actually occurs is the soft tissue structures become more contracted and tighter to hold the individual up and in particular on hard flat surfaces. These structures would have to do this for 3 reasons, to increase shock absorption, support a mobile structure and resist a hard surface. What is occurring inside the foot at a micro level would be displacement of bones with every single stride on hard surfaces, this then gives a further job of the muscle to perform and that is holding these displaced bones in place.
The final thing that must be considered by the die-hard barefoot runners is simple physics and in relation to why something will at some point give in relation to what I’ve just mentioned. This comes down to a matter of law – Newton’s 3rd Law in fact. For every action there is an equal and opposite reaction. As we know there is only one foot in contact with the ground at any one time whilst in motion (the gait cycle). If you weigh 70kg that is 70kg down one leg at one time, because there is absolutely no shock absorption from the ground that is 70kg back to you. This in affect equates to 140kg of weight passing through one leg and foot at a time.
Displacement of bones under this weight and stress will happen and eventually serious injury will result. In my clinical experience of these fades they die fast and are just plain silly. My recommendation is run on damp wet sand at the beach, if you want to run barefoot and watch the shock absorption take place on the surface beneath you.
Jason Thompson for GF
Biomechanical Myotherapist
AUSTRALIA
THANKS. That is exactly my point: “I’ve noticed my arches are flatter than ever”
Those who promote that barefoot running increases the arch height need to explain all these anecdotes.
Hi,
Lot’s of great articles on your blog.
I have run in minimalist shoes for the last 5-6 years, some in five fingers, and from last year also some of it barefoot. My impression, even though I have no precise measurement, is that my feet are flatter. But still a lot stronger, springier, feels better and more coordinated. My only problem is that when I now put on shoes I previously used to feel where ok, some of them feel terrible. This is mostly shoes with a pronounced arch support. They now feel like they are pressing up below my arch and create an overall feeling of being completely unnatural, unsupported, and out of balance, and they seem to hinder what seems to be the natural movements of my foot.
I have not perceived the higher arches issue as a main selling point of the barefoot crowd, but I guess to some it might be an important point. As long as the overall function, strength and coordination of the feet, and the body, improves, does it really matter if the arch is higher or lower? Obviously to claim barefoot activities achieves this for the general population it should ideally be backed up by more rigorous studies, but I am happy with my personal results of running longer with less injury problems, and enjoying my running more, even with flatter feet.
Thanks.
You are right, the arches are irrelevant and have no idea why so many focus on them.
My aim of this article (and many more to come) are to pick on claims made and dissect them, rather than blindly fall for the claims. That does not mean what I might be ‘picking’ on is good or bad, it just means the claims are nonsensical. I was picking on running shoes not impacting the injury rate since at least the mid 1980’s!
Hi,
Great blog – i share your fondness for thought experiments of the foot (but i don’t like talking in absolutes when describing gait or biomechanics) and have a couple of problems understanding your model –
* with main tibalis posterior attachments to midtarsals how can it significantly invert or supinate the rear foot while running – especially in barefoot/minimalist shoes with no rearfoot control. On ground contact doesn’t the calcaneus try to evert and abduct (resisting inversion) – surely MORE pronounced in minimal footware?
* “soft tissue contracture of the inverted forefoot on the rearfoot will stretch out and the medial longitudinal arch will take on a higher arch profile.” What soft tissue contracture is ‘stretching out’?
Thanks for your time
Mark, thanks.
The post tib tendon passes medial to the subtalar joint axis and has a significant lever arm to it –> powerful rearfoot inverter/supinator. It also passes posterior to the ankle joint axis –> plantarflexor (and also has more distal effects at the other joints it crosses). With forefoot striking the plantarflexors are more active, so post tib will be providing an eversion or supination moment at the rearfoot as it is more active. In some that will result in more supination and in others it won’t –> whichever happens will depend on the sum of all the moments acting at the joint. (and this variability from person to person, may account for some barefooters developing a higher arch profile and some not).
‘Forefoot supintus’ is a theoretical construct that sometimes needs a book written about to go through all the intricacies of it, so its hard to to justice to it here (I a planning a YouTube video to better explain it). The “contracture” i mention is probably twofold – mostly ligamentous and possibly a change in lever arms that tendons have to exert there effect in the forefoot due to the positional changes that occur. There is also some possible bony adaptation that takes place.
I just added this as a postscript above:
POSTSCRIPT: A study present at the 2013 ACSM mtg that reported the results of 39 runners after a transition to minimalist running shoes. They found no change in arch height (more).
No
Hi Craig,
Your though experiment is probably a good bet for explaining the anecdotal changes in arch height barefoot runners report.
I’d like to get your thoughts in regard to one aspect of the intrinsic muscles’ function. I agree that the intrinsics are too small and badly positioned to resist pronation on their own. It seems to me though that active plantar flexion of the first ray against the ground would increase the posterior tibialis’ ability to resist passive eversion of the rearfoot by providing a more stable fulcrum than if the forefoot just passively inverts. This would apply regardless of the type of foot strike used. In this way, the intrinsics would assist the posterior tibialis in controlling the rate and magnitude of pronation. What do you think?
In a “normal” foot the intrinisics don’t fire until the heel starts to unload, ie late in midstance – just look at the timing of muscle atviity in the anatomy textbooks and this is what they say (based on Basmajian’s orginal work). There role is [probably to plantarflex the proximal phalanges on to the ground to make the toes a stable platform for the foot to pivot about – that is probably too late in the stance phase to assist post tib in stopping ‘pronation’.
HOWEVER, in the flat pronated foot Basmajian also showed that they are active more earlier in the stance phase, so they are obviously trying to help with what you are suggesting. Kind of ironically, if they are more active for longer in the stance phase for a flat pronated foot than the ‘normal’ foot, then they ae probably stronger as they are working so hard. That makes a mockery of the propaganda that flat overpronated feet are due to weak muscles. Those who think it is, are going to have to explain this finding by Basmajian.
I’m not entirely convinced the intrinsics don’t play a role in supporting the arch. I’m with you that there is not a strong case that the intrinsics are responsible for overpronated feet. I’ve seen more recent studies than Basmajian though indicating the instrinsics are more active during the stance phase. I’ve also read studies showing a drop in navicular height with selective fatiguing of the intriniscs or lidocaine injection in the area of the tibial nerve distal to the ankle.
I believe Basmajian conducted the EMG study with the subjects wearing shoes. If these shoes were like most shoes and had a toe spring, wouldn’t the proximal phalanges be held off the ground in extension until the heel lifted off the ground? This might be one explanation for those findings. It seems to me that when walking barefoot the proximal phalanges would come in contact with the ground much earlier in the stance phase, and then would be better able to assist the posterior tib. I’m just speculating but that could be one of the reasons for those results.
There is one study that has shown that there is no relationship between muscle power and arch height; another study showing that exercises to increase the strength of those muscles did not affect arch height; however another unpublished abstract reported a decrease in arch height with intrinsic muscles exercises! The evidence certainly does not support the contention that strengthening the intrinsic muscles of the foot leads to an increase in arch height.
Im intrigued with the studies you selected. It just shows you dont understand spring stiffness because it is not muscle strength that would lift arch height when measured in the standing posture. The first study says nothing about what exercises were selected but ONLY those which increased explosive power. You really dont know if those muscles they selected have anything to do with arch height. So this is an invalid point unless you can dig up the actual research which showed if they did resistance exercises and which muscles were trained and how.
Resistance exercises can strengthen muscles very slightly in 4 weeks but have little impact on tendon strength. Also, you know that the research shows that muscle strength is not what would lift the arch but the spring stiffness. You know that research has shown that muscles react to the landing in running with a quasi-isometric contraction of the muscle with the tendons doing the majority of the work. http://jeb.biologists.org/content/201/11/1681.abstract?ijkey=51bd02b701bef5ddf14020568af2c5cbe10bc463&keytype2=tf_ipsecsha We also know that tendon strength takes more than 4 weeks to build with estimates of 10 – 16 weeks. So this 4 week study is not an adequate duration to determine if the tendon strength will improve to improve spring “stiffness” of the landing muscles which is the true determining factor in arch height. You really need to do more research to make these statements as your statements are misleading to the public based on your lack of depth of understanding. We also know that if athletes were running in a straight path then they were not doing the drills which would train the landing muscles that would improve spring stiffness and lift the arch. If they did barefoot plyometric drills or running drills in zig zag, figure eight, side shuffle etc for 16 – 20 weeks or more you might have a valid study to quote from and ONLY if you measured the arch height at mid stance and compared it to standing arch height of the before and after. This statement is misleading to those who wish to improve the depth of their arch mechanism
This study you selected shows me you are completely lost as to what it takes to strengthen the arch. First the study states that they exercised by lifting a towel with their toes. Are you trying to say that lifting a towel weighing 1 pound with the toes curling is an adequate strengthening program to develop arch height? Lifting a 1 pound towel isnt going to increase strength to lift the arch up to support a 150 pound man? This is silly. Also, intrinsic muscles do not lift the arch. We all know from research that the plantar fascia is ONLY responsible for 14% of the load to maintain an arch. http://www.ncbi.nlm.nih.gov/pubmed/7834064 So what holds the rest of the arch? Its not the intrinsic muscles of the foot, sir, but the tibialis posterior http://www.ncbi.nlm.nih.gov/pubmed/22749639 You really need to do more research on how the body resists impacts. You really dont understand the basics and you are leading these readers with inaccurate statements based on research that is completely in left field.
One small study (only 5 subjects) that was presented at the 2011 ACSM meeting showed no change in arch height after 6 months of minimalist running (abstract here). The study has not been published in full for proper peer review and appraisal.
What does general casual running with minimalist shoes have to do with plyometric impact training or running drills with the focus on the tibialis posterior muscle to improve arch height? Once again this is a misleading and irrelevant study to quote
When you look at the size of those muscles on anatomical dissection, they are extremely small. How can muscles that small have any impact on the height of the arch of the foot?
We have this abstract from the 2012 ACSM meeting that showed that: “barefoot running does not result in greater activation in these muscles compared to running shod. This suggests that barefoot running may not result in strengthening of the foot intrinsic muscles“.
If the intrinsic muscles are to increase the height of the arch, they do so by plantarflexing the metatarsals. These muscles run pretty close to parallel with the metatarsal, so have a very poor lever arm to plantarflex them. So how can those tiny muscles with a really poor lever arm come close to doing that, especially against body weight and the magnitude of forces generated during gait?
The answer is that they have nothing to do with arch height. http://www.ncbi.nlm.nih.gov/pubmed/22749639
The EMG studies on flatfoot show that the intrinsic muscles are very active, much more active than in a ‘normal’ arched foot. While I am the first to acknowledge that EMG does not equal muscle strength, but certainly would ask if they are more active in a flat foot, then they must be stronger than in a ‘normal’ arched foot where they are less active.
Once again, muscles, especially intrinsic muscles have NOTHING to LITTLE to do with arch height so irrelevant. Sorry… BTW Have you ever run barefoot yourself?
“Once again, muscles, especially intrinsic muscles have NOTHING to LITTLE to do with arch height so irrelevant. Sorry”
I never said they do! Its only the fan boys who make that claim.
“… BTW Have you ever run barefoot yourself?”
Yes
Anecdotal evidence is still evidence. No, it isn’t a double blind study, but it is still evidence. People who try and say anecdotes count for nothing don’t understand science.
Your point being?
There is no such thing as anecdotal “evidence”. An anecdote is not evidence.
Or as a famous running research PhD once said to me in talking about the claims of the barefoot and minimalist shoe running zealots;
“the plural of anecdote is not evidence.”
From what point of view are the researches taken? What company funded them? A company is more likely to support a research that ends up in their favor.
Also, I had flat feet and now I don’t anymore. I picked up barefoot running but not only that, I train my foot muscles specifically. But it’s really a process. Many people have never used their foot muscles properly because of shoes and stuff. And I don’t think only barefoot running increases foot strength. It’s a process to really get to know the feet. But believe me, my flat feet are gone. The key thing for me is, walk as lightly as possible, almost silent. That way you utilise the muscles the most.
It’s just too bad barefoot running is so looked down upon with all sorts of researches that take things too literal. And it’s not only the running, but getting to know your feet and strengthening them (a must) in general.
How then do you explain those who take up barefoot running and their arches get lower?
In my 30 years of examining tens of thousands of feet, I have never seen a runner that is a habitual shoe wearer have “weak feet”. On the contrary, runners generally have stronger foot muscles than their non-running counterparts, probably because of the muscle strength they develop from the increased muscular effort required by running.
Therefore, Raoul, if you want to believe that your feet went from being flatfooted to normal arched shape because you read Born to Run and started running barefoot, then that is your right to believe that. However, for every one like you that gives an anecdotal report that being barefoot is the best thing for their feet, there are just as many people reporting that running barefoot caused them pain and injuries that sometimes prevented them from running for months.
In addition, some of the fastest runners I have ever examined have very flat feet so having a higher arched foot may not be the best foot shape for runners. Maybe by you being so concerned about the height of the arch of your foot you have made yourself a slower runner but with a heavier, more muscle-bound foot. Have you ever considered that being higher arched may not, in fact, be helpful for all runners?
Kevin Kirby using anecdotes. Whatever next.