The peroneal muscles are not as well known as some of our other lower body superstar muscles, but they are vital for healthy gait mechanics, especially on uneven surfaces. Improper body alignment or wearing unsound footwear may not only create discomfort or injury to the peroneals, but to other muscles and joints also, near and far from feet and ankles. Before buying summer sandals, take a moment to consider the potential hazards in the shoe department and how flip flops can cause foot pain.

The peroneal muscles are vital for healthy gait.

The peroneus longus and brevis originate from outside of the fibula. The tendon of the stealthy peroneus longus passes below the 5th metatarsal, crosses the sole of the foot and inserts under the 1st metatarsal and cuneiform bones. This is a key component in the pulley/lever system of the foot; creating stabilization of the great toe during movement, balance, and especially walking gait.  In 1954, podiatrist John Hicks was the first to compare the marvelous arch mechanism of the human foot to a ‘windlass,’ a term taken from sailing and heavy equipment design.  Windlass describes a powerful winch where a cord is wound around a cylinder to lift a heavy load.  In the human foot, this effect is demonstrated when the plantar fascia (the ‘cord’) pulls from the calcaneus and toes dorsiflex, especially the big toe; where it coils around the metatarsal heads (‘cylinder’) to pull the “load” (you).

During the dorsiflexion of the big toe, the peroneus longus stabilizes gait. However, when wearing flip-flops, the big toe actually plantar flexes in order to grab the flip-flop and prevent it from slipping off the foot!   This partial destruction of nature’s amazing “windlass effect” is only one way flip-flops foster dysfunctional motor patterns in muscles of the foot, particularly in the peroneus longus, while hindering the plantar fascia from doing its job. This disruption of proper mechanics also renders the arch of the foot far less effective, allowing the “load” to move precariously above. This literally takes some ‘spring’ out of your step.  While high heels are known to cause postural dysfunction and injury, flip-flops may be the more stealthy ‘arch rivals.’

When irrational shoe selection must prevail for a special day, try to practice moderation and some self-care. Here is a great Yoga Tune Up® video demonstrating one way to improve mobility and strength in ankle and foot stabilizers, giving that extra care to your amazing ‘windlass’ soles:

Watch our free Quickfix video for feet and ankles

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Diane Marra

Diane Marra is an Exercise Physiologist and Biomechanics specialist with more than 20 years’ experience teaching in universities, hospitals, corporate and community settings. Diane holds a Master’s Degree in Kinesiology from California State University and numerous fitness certifications. Her scientific research, conducted for the US Army Medical Department and California State University, has been presented at international conferences and published in clinical journals. Today, Diane is creating new programs as the corporate Wellness Manager for a global manufacturing company and still teaches part-time for SUNY Buffalo State College. Since personally overcoming multiple injuries and chronic pain, Diane has a passion for helping ‘regular folks’ who sit too much, manage pain conditions, seek post-injury recovery, and/or simply want to be stronger. Current credentials include: National Strength & Conditioning Association (NSCA™-CPT), American College of Sports Medicine/ ExeRxcise is Medicine® ​Level 1, Yoga Tune Up® and TRX™ Diane is currently developing a new course for her SUNY Graduate students about Workplace Ergonomics and Selfcare, offers private training sessions and occasional workshops in the Buffalo-Niagara area while continuing to do free-lance research/ writing for Medical and Fitness publications.

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Emily Pantalone

Oh no!! I’ve heard flip flops are bad of you but now that I know why, I don’t think I shall ever be able to wear them guilt-free ever again! It’s interesting that the main reason they’re bad for you is the big toe grab… I wonder what style of flip flop (if any) could actually be ok for your feet?


During a YTU massage training, I was stunned to discover how achey these muscles were when I was rolling them out. No more flip-flops for me. Now on to some reatail therapy: smart shoe shopping. Here’s my new angle: “It’s for my HEALTH, dear husband! Lower those eyebrows!”

Alison Pignolet

What a clear explanation of the mechanics of the peroneals. I hadn’t realized the pulley effect. Very cool. Thanks, Diane!


Would appreciate any advice on relieving congestion in my foot following bunion surgery–a year later my big toe area is still inflamed and sore. Can this be related to wearing flipflops?


Even though I wear very minimalist shoes, my left plantar fascia is a chronic problem and I’m beginning to suspect my peroneals are to blame since I recently learned (and you re-confirmed this) that they wrap around the bottom of the foot and insert into the medial part of it. I’m hoping this is a large piece of my pain puzzle.
Thanks for the insight.

Deepa Dravid

Very informative article. Time to let go of the flip flops. Thanks!


Very informative, thank you. My feet scream at me (and cramp up if I wear flip flops), and I know that my peroneals need some extra time with the tune up balls. The relief is incredible. I will pass this information on.

Beverly N.

This is a really informative and interesting article. It makes me wonder if those yogi flip flops with individual toe spacers will have the same result. The poreneus longus sounds like a gait superstar. It’s unfortunate that more time is not spent understanding the relationship between the biomechanics of gait, postural alignment, injury and degenerative disorders. Thank you for this article.

Jason Campbell

ugh, but i love flip flops! Kelly Starrett just posted a video about this topic recently on Mobility Wod. I’ve heard for years that flip flops are bad for you, but i always assumed it had to do with more with the arch of the foot, it didn’t even dawn on me that you flex your big toe every time you lift the foot simple to hold the flip flop on! I’ll have to be on the search for a better sandal variation to wear in the summers here in Toronto where our summers are crazy humid and hot.


I will never look at flip flops the same. While I knew the ills that heels do to the body and the feet, I had no idea that flip flops cause just as much or more damage. I have mostly given up heels. Now I’ll have to venture out to find comfortable footwear for the summer!


I can’t tell you how much I wish this article didn’t describe me! I am always amazed at the ease that other people seem to have wearing flip-flops when my feet suffer with them. The desire to look cute has often outweighed good sense and I always end up wishing it hadn’t. Thank you so much for the foot fixes. Now I just need to focus on the right things and stop adding to the problem with poor choices in footwear.

Diane M

P.S. Dont forget the soleus and gastroc, too!!

Diane M

I love seeing people’s thoughts on this phenomenon. Rosemary – great observation re: your tibialis anterior! That muscle works in agonist/antagonist relationship with peroneals. Also – the ag/antag. tendons form almost a “stirrup” surrounding the foot for support. So…it makes sense to me that some folks (you) may notice more aggravation from your inversion/dorsiflexion muscle rather than the eversion/plantarflexion muscle. Bottom line: negative effects from wacky shoes can be felt. My article and video were limited to a particular muscle group, but I definitely recommend rolling out muscles that impact ALL DOMs of any area targeted. In this case, rolling… Read more »

Caitlin Vestal

Thank you for really breaking down what’s going on when you’re wearing flip-flops. They are my guilty pleasure, living in Austin, TX, where it’s always Summer, even though I know they’re not great for my feet and legs. Such a detailed breakdown of why they’re not so great helps hammer it home for me.

Blake Rogers

Growing up in Eugene Oregon us hippies always wore Birkenstocks. When i did wear flip flops i did notice my feet would get sore. It wasn’t until i was training with Tony Sanches and he told me how bad they were for my feet that i knew i would never wear them again. Now i know exactly whats going on in the foot when i wear them and how damaging they really are.


I never considered the impact of my beloved free little flip flops on my movement until my partner pointed it out. You’re tightening your heal cords he would say. Now here’s the article to support his statement. However I find I feel more restriction in tibialis anterior from my non so functional foot ware. I’ve since found myself in sneaks, but oh how I miss taking peaks at my pedicure. Maybe one day I can be barefoot everywhere.

Diane M

Hi Leslie, I enjoyed meeting you very much! We had a brilliant class in Ohio full of brains and talent!! The dark chocolate Teacher’s gift was indeed a blessing on the ride home through the pre-tornado storms! Big thank you!! Regarding your observation above; in addition to the lack of great toe gripping in boots I believe that the lack of lateral support in some types (big loose or sloppy fitting ugg-types) and the lack of flexibility for the MTP joint to allow proper toe pushoff at all (think of our bunion lessons of the body’s “laying down bone” where… Read more »

Leslie Wright

Hi Diane, I remember Jill’s mentioning the hazards caused from wearing flip flops last March in Toronto when we were all stomping around in boots. (It is interesting how one latches on to a scrap of information). She did not, however, have the time to elaborate why we should avoid them. Now I know: it is the plantar flexion of the big toe gripping to keep the shoe on when the toe ought to be allowed to dorsiflex to push the foot off the ground. It disturbs the normal, healthy movement pattern. I will save one pair of flip-flops only… Read more »


I love flip flops and can’t imagine doing away with them. I do, however, try to wear the most appropriate shoes for what I’m doing. What makes all the difference for me is making sure my shoes fit properly with enough width and space for the toes and the widest part of my foot. I always notice if the shoes are wrong for the occasion (flip flops combined with a lot of walking) or I’ll-fitting (but they were so pretty) and the pain/discomfort can travel all the way up the body. I love having more specific information about where this… Read more »


Diane! Great article and lovely meeting you this weekend 🙂 I am totally guilty of this and have felt the pain when transitioning from tennis shoes/boot to flip flops in the summer. It is hard to break the habit, but I will take advantage of the great stretches shown in the video to help take care of my precious feet.

Gary Carlisle

Studying the body is more than full time job. No wonder one yoga pose could yield a lifetimes of information about life.

My feet thank you for all your knowledge.

Meghan Cowens de Sturdze

As a South Floridian it is almost impossible not to own a flip flop or two. I always find is crazy when my back pain patients come in wearing them and they wonder why their pain in not getting better. The flip flop is so detrimental to good gait mechanics and can foster an environment ripe for pain all along the leg chain. The peroneals are an often overlooked workhorse, as fara walking is considered, and they do not get much love. Thank you for bringing some love to the lower lateral leg!


I know how bad flip flops are but everything else hurts my feet, even my sneakers! Flip flops are the only shoes I can wear without constant pain. I have bunions on both feet and flat feet and I pronate (very attractive)…what about fit flops??

Diane M

Maria and Layla– Glad that you are finding relief… please check Jill’s you tube YTU Ball Videos for Anterior Tibialis to avoid shin splints and keep the area supple. Basically balls in the tote on a surface leaning the shin in between YTU balls and chug up and down with a ball along either side of the shin. Of course – with or without abuse of heels or crazy shoes— doing all the lower leg muscles is the best practice:)

Cynthia Bunt-Gardner

Great article. I can see how that plantar flexing of the big toe to hold onto the flip flop would truly throw a wrench into the mechanics of proper foot movement while walking. In addition to the peroneals becoming tight, I can see how tibialis posterior would become tight leading to a less functional arch and eventually the navicular bone could drop resulting in a dropped arch.
Hmmm….could flip-flops eventually lead to the “Frankenstein Walk”?


Wish I had read this article sooner! The first summer I moved to NYC from the suburbs, I was walking all over the crazy uneven sidewalks in my foam flip flops. After a couple weeks I had chronic pain and tightness on the outside of my calf (peronius brevis). I thought it was something that I could stretch out in yoga and dance, but stretching it was painful (I believe now it was inflamed, not only tight). I learned from experience and started wearing sneakers more, but very enlightening post!


Diane, What a great article! As a (particularly short) young female who lives and works in Manhattan, I have become accustomed to wearing rather high heels. I have, of course, heard how detrimental they are to my leg and foot health but can’t imagine giving them up. I have a foot stretcher that I keep at work but the exercises you demonstrated in your video look like they will be amazingly helpful. I also suffer from shin splints (i’m sure the shoes don’t help) and can’t wait to see if a regular practice of this stretch helps alleviate that pain… Read more »


What a great topic to cover! You always hear about how bad heels are for your feet, but i never really stop to think what thongs are doing! (And i wear them all the time!). This certainly will make me consider more than just the color and style of my next shoe purchase. I also found the stretches to help alleviate my shin splints. Great article!

Morgan Ward

About two years ago I started experiencing horrific pain while doing any standing balancing pose. It was classic shin splints—but I did not (and do not) run. I tried everything to alleviate the pain, but nothing worked. Even after talking to countless yoga teachers I couldn’t find the solution. It wasn’t until I brought up my issue to my restorative yoga teacher that she offered some insight. I was completely neglecting my arch support–wearing flip flops and uggs the majority of the time. I switched my footwear, and bought insoles for my shoes and experienced an almost instant relief in… Read more »


Ha!! This is my wake up call. As a flight attendant, I work with a lot of people who wear high heels and flip flops and alternate them back and forth!!! A lot either have plantar problems or peronial pain. Jill’s video was so challenging!! I have some work to do!!!!

Diane M

Hi Oliana,
Thank you for sharing your experience…. the YTU exercises for feet and toes have been a wake up call for me also. I was doing some restorative work after a few ankle/foot injuries — but have deepened my efforts since working with Jill– and it is indeed worth it. Great reminder to anyone who reads this blog….. Jill makes it look easy but it is definitely challenging for most at first. Hang in there! Flirtier feet is the way to go!!!


Performing the exercise on the video above used to bring tears to my eyes at first. That’s how tight the soles of my feet were, mostly due to mindless choice of footwear. It took a lot of discipline to go through the first phase of pain, and although gaining flexibility of the plantar fascia is still work in progress, it has gotten quite easier. And my feet have become flirtier.


Thank you so much for this!!!! I am guilty of wearing flip flops because they are easy especially in NYC when I am walking around, but I notice some times that if I’ve had them on all day, that my ankles and shins start to bother me. The comfort that I’m going for while wearing the flats–specifically flip flops ends up causing more discomfort in the long run. I tried the stretches that you recommended today and I feel immediate relief.

Diane M

Hi Gary, I like sandals similar to the Merrell Midway (for men), which offers a nice footbed with spac for toes, a heel strap whch helps avoid the unfortunate ‘flip-flop-flexion” of the toes, allowing maintenance of normal toe extension during gait-with good lateral support for any terrain- including hard man-made surfaces. I’ve recently come across some of Katy Bowman’s (of ‘Aligned and Well’) brilliant writing on feet and shoes that is worth reading too… Hope you are having a super summer!

Gary Carlisle

Does any one know of any sandals that are suitable for summer ware?

Renee holden

Great blog Diane!
I learned very quickly quite a few years ago the relationship between flip flops and our peroneals, on a driving road trip to Florida, in the summertime, wearing flip flops, I began to have incredible discomfort in my peroneals. I began to realize that between constant plantar flexion from driving, and then wearing unstable flip flops, I had injured myself!
I now have recognized that a isometric contraction for hours on end, and no arch support from an unstable footwear is a recipe for disaster!


While just learning the terminology, from an early age I only wore Flip Flops for short distance walks precisely to avoid the unnatural feeling of the plantar flexion movement of my toe. I recall all the times my friend’s and I were forced to wear FFs for more than 30 minute intervals; feeling a vine of tightness begin to form up the side & front of one or both shins and sometimes through the middle of the foot. Thanks, great article.

Diane M

The purpose of the strap is to hold your ankles and lower legs in essential optimal alignment; I would not eliminate the strap. The tightness you feel sounds like a signal that something else needs work and is not typical, however, this is uncomfortable for many people….. so start slow. You sound like a good candidate for thoroughly rolling out all areas of your lower legs and feet with YTU balls before trying this exercise again. If you feel safe and do not experience any pain- you may want to start with less time in the pose and gradually tolerate… Read more »

Nicole Shahida

Is it still possible to get the same benefits from the stretch without using the strap? I feel a tremendous pulling on the inside of my ankles, is this a normal sensation?

Margo Brooke Pellmar

Thank you so much, I love the imagery of my ankles being able to breathe. I’m never in shoes because of my yoga practice and teaching. I used to have amazing arches and now I’ve been told my inner arches are collapsing!!! I’m so happy to open my ankles and fascia of my feet. Summertime is especially tricky because you are either wearing heels or flat flat flipflops, so the feet take a brutal pounding. Not to mention, I’m a runner. I love to do this pose reclining on my forearms and then lowering onto my back while having my… Read more »

Pat Donaher

I cringe every day when I see my students walking into class in flip-flops, then giving me the death stare when I put them in Seza. It’s great to have this specific, detailed “why” when students ask. That said, I’d be interested to hear more feedback here on proper footwear, especially with the five-finger and other minimal shoes being all the rage right now. I love them, but I also don’t exercise in ways that are putting repetitive stress on my feet. I’d be interested in other thoughts on the broader footwear conversation.


Beautiful description of the machine we call the foot. It truly is an amazingly constructed body part! Unfortunately,I LOVE flip flops. Actually, I hate shoes which is why I LOVE flip flops. In the Hot NYC summers I can’t think of anything worse than putting my feet into those little foot heaters people call shoes. And NO, I am not going to wear those good for me sandals. (I actually wear sneakers all day at work!) However, I do realize that my flip flop addiction requires me to take the utmost care of my feet and lower leg. I am… Read more »

Jiin Liang

Thanks very much for this article explaining how flip flop may compromise our feet and the use of peroneal muscle. I wonder if the wooden Japanese flip flop would be OK, since the wooden sole is leveled and can rock forward and back. I also notice that in addition to peroneal muscle, the engagement of inner thighs and an appropriate degree of external hip rotation help to support the arch. This new awareness while walking has corrected my pronated arches, also know as flat feet.


…oops- smartphone typing. So finally; my personal preferences… when walking only on soft pine needle forest floor and sandy beach I love to be barefoot. Otherwise I am often wearing a good pair of athletic sneakers. I shop carefully for low dress shoes with a decent foot bed/ arch and comfy toe area with enough straps on open shoes to keep them on my feet ( e.g. lateral straps, slingback, etc.) But, like everyone I have my “individual differences + history of injury ( as noted in your posted website ‘nwfootankle’), which determines which shoes allow my post-ballet feet/ankles to… Read more »


Hi Tracy, Thanks for the thoughtful and thought provoking post. I am out of internet range so trying to read the links you sent via my smartphone, so please forgive me if I miss something here. It seems one of the articles at least pointed out the concept of adaptation which is a big issue in modern society. The fact that we’re protecting our feet from hazards has pulled us away from natural minimalist/ native footwear and because of “specificity of training” principles we have adapted. So…. like any “training” our feet need to adapt slowly to minimal support +… Read more »

Tracy Hodgeman

Thank you for this article, Diane. I have been following the conversation about healthy footwear with great interest. One article I read recently ( says the shoe should be completely flat, with a flexible sole and the toe bed wider than the heel to allow for toes to spread out. This article seemed to think flip flops were ok. They also liked crocs (as long as they followed the rule of flat, bendable sole, and wide toe bed). Then I read another article that said flip flops were bad news for some of the same reasons you mention above (… Read more »


It’s such a privilege to be part of this elite body of YTU Teachers. Diane, I never would have given this subject any thought at all before reading your blog. I now have a much more knowledgeable purpose when I put my students into Toe Pose. Thank you.

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Kristen B.

Great article Diane! I have been noticing some tension in my arches when I am playing with isolating plantar/dorsiflexion of my big toe and wondering where that might be coming from. Your suggestion makes me think more about my choice of footwear being the culprit. I will wear better shoes this week and see if things change!

Helen McAvoy

Great information…. I admit I wear flip flops in the summer…(easy to slip on/off) Absoultely will rethink this and invest in some decent sandals. The information regarding he peroneus brevis and function is helpful going forward with rolling out and mobility exercise. thank you!!!