Flat shoes can absolutely cause ankle pain, and the mechanism is less obvious than most people assume. Unlike high heels, which force the foot into an unnatural position, flat shoes create problems through what they lack: cushioning, arch support, and heel elevation. Research shows that walking in flat shoes produces significantly higher pressure in the heel region compared to running shoes, changes how the ankle joint moves through its range of motion, and can increase shear forces at the ankle. The story is more nuanced than “flat shoes bad,” though, because the type of flat shoe, your foot anatomy, and how long you wear them all matter.
How Flat Shoes Change the Way Your Foot Handles Impact
Every time your heel hits the ground, the shoe’s construction determines how that force gets distributed across your foot. Flat shoes, whether ballet flats, basic canvas sneakers, or dress loafers, typically have minimal or no insole construction to absorb shock. A study comparing in-shoe pressure across flat shoes, running shoes, and high heels found that because flat shoes lack the cushioning architecture of running shoes, the impact during heel strike hits the hindfoot region much harder. Peak plantar pressure and the total pressure over time were both elevated in the heel region of flat shoes compared to running shoes, meaning higher pressure occurred for a longer duration with each step.1PubMed Central. Change of In-Shoe Plantar Pressure According to Types of Shoes (Flat Shoes, Running Shoes, and High Heels) The researchers noted that this pressure pattern closely resembled the barefoot condition, where the hindfoot, second metatarsal head, and big toe bear the highest loads.
That concentrated heel loading matters because the ankle is the first major joint in the chain that absorbs and redirects ground forces. When the heel pad and shoe sole fail to dampen impact, the ankle’s tendons, ligaments, and joint surfaces pick up the slack. Over hundreds or thousands of steps per day, the cumulative load adds up. The same study specifically cautioned that flat shoes may not be appropriate for people already dealing with plantar fasciitis, because the overloading can excessively stretch the plantar aponeurosis, the thick band of tissue running along the bottom of the foot that connects to the heel bone and influences ankle mechanics.2PubMed Central. Change of In-Shoe Plantar Pressure According to Types of Shoes (Flat Shoes, Running Shoes, and High Heels) – Section: DISCUSSION
What Happens at the Ankle Joint Itself
Beyond pressure distribution, flat shoes change the angles and forces at the ankle during walking. Research on flat-flexible shoes found that they increased the maximum ankle dorsiflexion angle (how far the foot bends upward toward the shin) while significantly reducing the maximum plantar flexion angle (how far the foot points downward at push-off).3PubMed. Effects of flat-flexible shoes on lower limb joint kinetics and kinematics in gait In practical terms, this means the ankle moves through a different range with each stride compared to how it moves in a supportive shoe. More dorsiflexion puts additional stretch on the Achilles tendon and calf muscles, while less plantar flexion can reduce the efficiency of your push-off.
These kinematic shifts are subtle per step but persistent across a full day of walking. If you spend eight hours in ballet flats or similarly unsupportive flat shoes, your ankle has been functioning in a slightly altered range for thousands of cycles. For many people, this altered movement pattern is the starting point for the dull ache around the ankle or the stiffness that appears after a long day on your feet.
The Flip-Flop Problem
Flip-flops deserve their own discussion because they are among the most common flat shoes and they introduce a unique biomechanical quirk. A study measuring ankle joint contact forces found that both barefoot walking and flip-flop walking produced significantly higher shear forces at the ankle compared to sports shoes.4PLoS ONE. Lower limb muscle co-contraction and joint loading of flip-flops walking in male wearers Shear forces are the side-to-side and front-to-back forces acting on the joint, as opposed to the compressive forces pressing straight down. Higher shear forces mean the ankle’s stabilizing structures, particularly the lateral ligaments, work harder with every step.
Flip-flops also force you to change how you walk in order to keep them on your feet. Research on flip-flop biomechanics found that wearers adapted their ankle motion at heel strike, toe-off, and during the swing phase of gait, trending toward more dorsiflexion compared to barefoot walking. This adaptation appears to be a gripping mechanism: because the dorsal strap only covers the front of the foot, you subconsciously modify your gait to prevent the shoe from flying off.5PubMed Central. Does flip-flop style footwear modify ankle biomechanics and foot loading patterns? Some researchers have attributed this to contraction of the toe flexors creating a plantar-flexor moment at the ankle, essentially making the muscles around your ankle and foot work overtime just to keep your shoes on.
The practical upshot: flip-flops combine the zero-cushioning problem of flat footwear with an added layer of compensatory muscle work. If you wear flip-flops for a quick errand, the extra ankle stress is trivial. Wear them for a day of sightseeing or around an amusement park, and you may feel the consequences in your ankles and lower legs for days afterward.
When Flat Shoes Stress the Achilles Tendon
One of the most common pathways from flat shoes to ankle pain runs through the Achilles tendon, the thick cord connecting the calf muscles to the heel bone. A shoe with even a modest heel elevation shortens the distance the Achilles tendon has to stretch during walking. Remove that elevation entirely, and the tendon is asked to lengthen more with every step. Research on barefoot and minimalist footwear found that while these shoes may reduce loading at the knee, they correspond to increases in Achilles tendon loading that could raise injury risk at that tendon.6PubMed. Effects of barefoot and barefoot inspired footwear on knee and ankle loading during running
This becomes especially relevant for people who typically wear heeled footwear and then switch to flats. Habitual heel wearing has been shown to significantly decrease dorsiflexion range compared to flat shoe wearers, meaning the calf muscles and Achilles tendon adapt and shorten over time.7Annals of Punjab Medical College. The Impact of Habitual Heel Wearing on Calf Muscle Tightness If you spend most of your week in shoes with a heel and then wear flat sandals all weekend, you are asking a shortened tendon to suddenly work through a much larger range. That mismatch can produce pain behind the ankle, stiffness in the morning, or an aching sensation along the back of the lower leg.
The relationship also works in the other direction. People who have worn nothing but flat shoes for years and then decide to try minimalist or barefoot-style footwear may experience similar issues. A study on people transitioning to minimalist footwear or barefoot walking found that roughly a quarter reported Achilles strain, and over half of those who transitioned developed plantar fasciitis, significantly higher than the rate among those who did not transition.8Journal of Health, Wellness and Community Research. Prevalence of Plantar Fasciitis and Achilles Strain Among Officers Transitioning to Minimalist Footwear and Barefoot Walking The message from this research is consistent: abrupt changes in heel-to-toe drop, whether going from heels to flats or from supportive shoes to minimalist ones, put the Achilles tendon and surrounding structures at risk.
The Surprise About Mid-Height Heels
One of the more counterintuitive findings in footwear research is that completely flat shoes and high heels both come out poorly compared to shoes with a moderate heel. A study measuring center-of-pressure displacement and foot pressure distribution after one hour of walking found that both flat shoes (about half a centimeter of heel height) and high heels (9 cm) produced significant adverse changes, while mid-heeled shoes (4 cm, roughly an inch and a half) did not.9Journal of Physical Therapy Science. The Changes of COP and Foot Pressure after One Hour’s Walking Wearing High-heeled and Flat Shoes The researchers concluded that mid-heeled shoes were preferable to both extremes for foot health and comfort.
This does not mean everyone needs to wear heeled shoes. What it suggests is that a small amount of heel elevation, whether built into a shoe or achieved through an insole, helps distribute forces more evenly than a dead-flat sole. Many athletic shoes, hiking boots, and casual sneakers already have a heel-to-toe drop of around 8 to 12 millimeters, which provides enough elevation to take some tension off the Achilles while still keeping the foot in a relatively neutral position. The worst-case scenario for ankle comfort tends to be shoes that are both completely flat and completely unsupportive, like thin-soled ballet flats worn on hard surfaces all day.
Your Foot Shape Changes the Equation
Not everyone responds to flat shoes the same way, and a big part of that comes down to foot arch height. People with flat feet (low arches) and people with high arches both face distinct challenges, but flat shoes tend to be harder on those with flat feet. Research comparing the natural gaits of people with flat feet and high arches found that flat-footed individuals experience greater variation in how their foot contacts the ground while walking, along with higher muscle tension under the foot. The flat-footed group fatigued more easily during long walks, and the difference was statistically significant.10PLoS ONE. Natural Gaits of the Non-Pathological Flat Foot and High-Arched Foot
When a flat-footed person wears flat shoes with no arch support, the foot rolls inward more (overpronation), and that inward roll cascades upward through the ankle. The ankle joint ends up absorbing rotational forces it is not well designed to handle on a repetitive basis. Over time, this can contribute to medial ankle pain, posterior tibial tendon irritation, and general fatigue around the inner ankle. People with high arches face different issues, such as excess pressure on the heel and ball of the foot, but the ankle-specific complaints tend to be more pronounced in flat-footed individuals wearing unsupportive shoes.
Running in Racing Flats
The conversation about flat shoes and ankle pain extends to athletic footwear. Racing flats, the lightweight low-profile shoes used by competitive runners, are designed to be fast rather than protective. A study comparing ground reaction forces across running shoes, racing flats, and distance spikes found that in male runners, racing flats produced significantly greater loading rates, peak vertical impact forces, and peak braking forces compared to standard running shoes at the same speed.11PubMed Central. Ground reaction force differences between running shoes, racing flats, and distance spikes in runners The researchers noted that injury risk may increase because the body is not accustomed to absorbing those greater forces.
For recreational runners, this matters if you have been training in well-cushioned shoes and decide to race in flats or switch to lower-profile shoes for daily runs. The ankle joint absorbs a large share of the increased impact, and Achilles tendon strain, ankle joint irritation, and stress reactions in the foot are all possible outcomes if the transition is too fast. Most running coaches and sports medicine professionals recommend increasing time in lower-profile shoes gradually, perhaps starting with short sessions and adding distance over weeks rather than days.
Standing All Day in Flat Shoes
Walking is one thing, but prolonged standing in flat shoes presents its own set of problems. When you stand in place, the sustained load on the same structures without the cyclic relief that walking provides can accelerate fatigue, particularly in the calf muscles that stabilize the ankle. Research comparing muscle fatigue during prolonged standing in different types of footwear found that stable flat shoes produced significantly higher rates of fatigue in the calf muscles (specifically the medial gastrocnemius on both sides) compared to shoes with a slightly unstable rocker-type sole.12International Journal of Occupational Hygiene. Evaluating the Fatigue Rate of Lower Leg Muscles during Prolonged Standing: A Comparison between Stable and Unstable Footwear
Fatigued calf muscles do a worse job of stabilizing the ankle, so if you work a job that requires hours of standing on hard floors, such as retail, hospitality, or healthcare, flat-soled shoes with no cushioning are a recipe for ankle discomfort by the end of a shift. Anti-fatigue mats help, but the shoe itself is the more important variable because it travels with you. Shoes with a small amount of cushioning, some arch support, and a slight heel elevation tend to keep calf fatigue lower and, by extension, keep the ankle more stable and comfortable throughout a long standing shift.
Do Orthotics Fix the Problem
Given how often foot orthotics are recommended for people with flat feet or foot pain, you might expect strong evidence that slipping an insole into your flat shoes resolves ankle-related complaints. The reality is less encouraging. A systematic review of evidence for foot orthoses in adults with flatfoot found a surprising lack of solid data. The researchers noted that despite how commonly foot orthoses are prescribed, the evidence base is weak and there is a clear need for better-designed trials.13PubMed Central. Evidence for foot orthoses for adults with flatfoot: a systematic review
That does not mean insoles are useless. Many people report feeling better with arch support, and some biomechanical logic supports the idea that correcting overpronation reduces abnormal forces at the ankle. But the honest state of the science is that we do not have strong randomized-trial evidence showing that orthotics reliably prevent or treat ankle pain caused by flat footwear. A more evidence-backed approach, at least based on the pressure and force research described above, would be to change the shoe itself rather than trying to retrofit a flat shoe with an insert. Choosing a shoe with built-in cushioning, some arch contouring, and a modest heel-to-toe drop addresses most of the mechanisms that link flat shoes to ankle pain, without relying on an add-on whose effectiveness remains uncertain.
Practical Guidance for Avoiding Ankle Pain in Flat Shoes
If you enjoy wearing flat shoes and do not want to give them up entirely, a few strategies can help reduce ankle-related problems. Limiting the duration is the simplest: wearing ballet flats to dinner is a different proposition than wearing them for a full workday. Alternating between flat shoes and shoes with some structure gives the Achilles tendon and ankle joint a break from the sustained extra loading. If you are transitioning to minimalist or barefoot-style shoes for philosophical or comfort reasons, the research strongly suggests doing so gradually over weeks to months rather than all at once, given the high rates of Achilles strain and plantar fasciitis observed among people who switch abruptly.8Journal of Health, Wellness and Community Research. Prevalence of Plantar Fasciitis and Achilles Strain Among Officers Transitioning to Minimalist Footwear and Barefoot Walking
Calf stretching and eccentric heel-drop exercises can help maintain Achilles tendon flexibility, which partially offsets the increased demand that flat shoes place on that tendon. If you have flat feet and know you overpronate, choosing a flat shoe with a slightly stiffer midsole or a wider base provides more lateral stability than a flimsy ballet flat or a narrow sandal. And if you are on your feet all day, prioritizing a shoe with even modest cushioning over a thin-soled flat is one of the simplest changes you can make to spare your ankles from cumulative stress.
When Flat Shoes Are Actually Better
The relationship between footwear and ankle pain is not a straightforward case where more support always wins. Research on barefoot-inspired shoes found that they may help reduce knee loading during running, which is meaningful for people dealing with runner’s knee or other anterior knee problems.6PubMed. Effects of barefoot and barefoot inspired footwear on knee and ankle loading during running The tradeoff is increased Achilles tendon load, but for someone whose primary complaint is knee pain rather than ankle pain, that tradeoff could be worthwhile. Some physical therapists also use brief periods in flat or minimalist shoes as a training tool to strengthen the intrinsic muscles of the foot and the muscles that stabilize the ankle, with the logic that a shoe that does too much of the work leaves those muscles weak.
Ballet dancers offer an interesting case study. Despite spending much of their time in essentially flat slippers, trained dancers develop exceptionally strong foot and ankle musculature through years of progressive conditioning. The injuries they experience tend to come from extreme positions (full pointe, repeated deep pliés) and poorly fitting footwear rather than from the flat slipper itself.14Journal of Orthopaedic & Sports Physical Therapy. Injury in ballet: a review of relevant topics for the physical therapist The takeaway is that a well-conditioned foot and ankle can handle flat shoes well. The problems tend to arise when the structures are not conditioned for the demand, either because of a sudden switch, a naturally hypermobile or flat foot, or hours upon hours of exposure without adequate strength.