Foot Strength and Arch Function: A Neglected Foundation

By Charlotte Evans

Who This Matters Most For

The Foot as a Living Spring, Not a Static Arch

Most people picture the arch of the foot the way it appears in a shoe-store diagram: a curved line of bone between heel and toes, propped up like a small architectural vault. That picture is not wrong, but it is incomplete. The bony arch (formed mainly by the calcaneus, talus, navicular, cuneiforms, and metatarsals) gives the foot its basic shape, but the structure only functions as a spring because of the soft tissue wrapped around and beneath it.

Two tissue systems do most of the work. The first is passive: the plantar fascia, a thick band of connective tissue running from the heel to the base of the toes, along with the long and short plantar ligaments and the spring ligament under the talus and navicular. These structures stretch slightly under load and recoil, storing and returning mechanical energy the way a leaf spring does in a vehicle suspension.

The second system is active: a set of small muscles that live entirely within the foot itself, known as the intrinsic foot muscles. These include the abductor hallucis, flexor digitorum brevis, quadratus plantae, and interossei, among others. Unlike the calf muscles that cross the ankle from outside the foot, these muscles start and end inside the foot and act like the cables of a suspension bridge, adjusting tension moment to moment as the arch flattens and recoils with each step.

One of the clearest illustrations of this cooperation is the windlass mechanism. When the toes extend during the push-off phase of walking or running, the plantar fascia winds around the metatarsal heads the way a rope winds around a winch drum, which shortens its effective length and pulls the heel and forefoot closer together, raising the arch and stiffening the foot for propulsion. Research published in Proceedings of the Royal Society B examined how the plantar fascia’s own extensibility, meaning how much it stretches under tension, changes how much work the windlass mechanism has to perform during running, showing that stiffer or more compliant tissue shifts the load-sharing between passive tissue and active muscle in measurable ways. A related 2025 analysis in Scientific Reports revisited the load-bearing roles of the plantar fascia and intrinsic foot muscles within the windlass system, reinforcing that the two do not act independently. When one is weak or fatigued, the foot leans harder on the other, and the intrinsic muscles are usually the more trainable half of that partnership.

In practical terms, arch “function” is not really about how high or low your arch looks when you stand still. It is about how well that spring can load, store energy, and release it again thousands of times over a run, a shift on your feet, or a long walk with the dog.

Why Modern Footwear and Daily Habits May Quietly Weaken the Foot

A supportive, cushioned, arch-contoured shoe is comfortable for a reason: it does some of the mechanical work the foot would otherwise do for itself. Rigid soles limit how much the toes and forefoot need to grip and adjust. Built-in arch support reduces the demand on the muscles that would normally control arch flattening. Thick cushioning dulls the sensory feedback from the sole of the foot that helps fine-tune muscle activity in real time. None of this happens because shoes are poorly designed; it happens because that is largely what supportive footwear is built to do, and most people wear some version of it for the majority of their waking hours.

Over years, this can function like a very slow, very mild form of disuse, comparable in principle to how a limb in a cast loses strength even though nothing is technically wrong with the muscle tissue. A widely cited 2018 comparison published in Scientific Reports looked at Tarahumara men in northwestern Mexico, who habitually wear thin minimal sandals, against an age-matched group of conventionally shod men in the United States. The minimally shod group had roughly 9 percent greater arch height, about 27 percent greater static arch stiffness, and a meaningfully stiffer arch during actual walking. Low arches showed up in only about 1 percent of the minimally shod men compared with roughly 31 percent of the conventionally shod group. The authors framed the difference as consistent with the idea that habitual footwear use is associated with weaker intrinsic foot muscles and reduced arch stiffness over a lifetime, rather than concluding that shoes cause acute damage.

Footwear is only part of the picture. Long hours of sitting, less time spent walking on varied natural terrain, and a general decline in barefoot or minimally shod activity across childhood and adulthood all reduce the variety of load the foot experiences. Muscles adapt to the demands placed on them, and a foot that spends most of its life on flat, cushioned, predictable surfaces inside a rigid shoe simply is not asked to do very much active stabilizing work.

The encouraging part of this picture is that intrinsic foot muscles respond to training the same way any other skeletal muscle does. A 2021 study from the University of Liverpool followed adults who transitioned into minimal footwear for at least 70 percent of their daily shod time over six months and found toe flexor strength increased by roughly 57 percent, with no significant change in a control group who kept wearing their usual shoes. A long-term comparison group who had already used minimal footwear for two and a half years or more showed similar strength levels to the six-month group, suggesting that much of the adaptation happens within that first several months rather than requiring years.

What the Research Says About Foot-Strengthening Exercise

The exercise most commonly studied for arch function is the “short foot” exercise, sometimes called the foot doming or foot core exercise: standing or sitting, keeping the toes flat and relaxed, and drawing the ball of the foot toward the heel without curling the toes, which shortens the foot and lifts the arch through active muscle contraction rather than toe gripping.

A 2022 systematic review and meta-analysis in PLOS ONE pooled 16 intervention studies covering 627 participants, including elite runners, people with flat feet, and healthy adults. It found that intrinsic foot muscle training produced a statistically significant reduction in navicular drop (a measure of how much the arch collapses under load) with a mean difference of about −1.97 millimeters, and a significant improvement in the Foot Posture Index, a standard clinical scoring tool, with a mean difference of about −0.69 points. Multiple studies in the review also reported improved dynamic postural balance following foot muscle training, although the balance-testing methods varied too much between studies to combine into a single pooled estimate. Interestingly, the review did not find consistent increases in the cross-sectional area or thickness of the muscles on imaging, suggesting that at least part of the functional improvement comes from better neuromuscular control and coordination rather than visible muscle growth alone.

Trials in specific populations tell a more mixed but still informative story. A four-week randomized controlled trial published in the Journal of Preventive Medicine and Public Health, conducted in Thailand with 36 adults who had flexible flatfoot, compared short foot exercise alone against short foot exercise combined with neuromuscular electrical stimulation of the abductor hallucis muscle. Neither group showed a statistically significant change in navicular height over the four weeks, a reminder that structural arch shape can be slow to shift even when exercise is performed consistently. However, the combined group did show significant improvements in abductor hallucis muscle activity and cross-sectional area compared with exercise alone, indicating that the muscle itself was adapting even before any visible change in arch height appeared. This lines up with a broader pattern in the literature: strength and control improvements tend to show up before, and sometimes without, dramatic changes in static arch measurements.

Research in children points in a similar direction from a different angle. A 2024 study in the Journal of Sports Sciences examined primary school students who wore minimalist school shoes over an extended period and reported improvements in intrinsic foot muscle size, strength, and arch integrity compared with children in conventional school footwear, suggesting the training effect of reduced-support footwear is not limited to adults who deliberately take up foot exercises.

Foot strength work also has a documented role in healthy aging. A systematic review summarized by the McMaster Optimal Aging Portal analyzed nine studies involving 1,674 community-dwelling adults aged 65 and older and found that programs combining toe and foot exercises, minimally cushioned footwear, and resistance work, performed for 10 to 45 minutes on 1 to 7 days per week over 6 to 12 months, improved toe strength, balance, and some aspects of functional mobility, with evidence suggesting a reduced rate of falls. The same review noted that these programs did not reduce participants’ fear of falling, which is a useful distinction between physical capacity and psychological confidence.

A Visual Guide to the Arch-Support System

The diagram below is a simplified, side-view representation of how the passive and active support systems share the load of standing and walking. It is not anatomically exact, but it illustrates the relationship between the bony arch, the plantar fascia beneath it, and the intrinsic muscles layered just above the fascia.

A Progressive Foot-Strengthening Routine

The routine below follows the same principle used in most of the studies above: start with basic muscle activation, then add load, balance demand, and dynamic movement over roughly eight to twelve weeks. Perform the exercises barefoot on a firm, flat surface unless noted, and progress only when the current stage feels controlled and pain-free.

Copy-Ready Checklist: Building Foot Strength Into Your Week

A Worked Example: Maria’s Twelve Weeks

Common Mistakes to Avoid

What Podiatrists and Physical Therapists Say

Clinicians who work with feet day to day generally frame foot strengthening as one useful tool among several, not a replacement for orthotics, footwear changes, or medical treatment when those are genuinely needed. Physical therapists commonly describe the short foot exercise as a way to “teach” the nervous system to recruit the intrinsic muscles that many adults have simply stopped using, since the movement pattern itself, not just muscle size, appears to drive much of the functional benefit. This lines up with the PLOS ONE review finding meaningful improvements in navicular drop and foot posture without significant increases in measured muscle bulk.

Podiatrists tend to be more cautious about applying a one-size-fits-all approach, particularly for patients with rigid flat feet, significant structural deformity, or conditions like posterior tibial tendon dysfunction, where the mechanics involved go beyond what intrinsic muscle training alone is likely to resolve. In those cases, exercise is often recommended alongside, rather than instead of, orthotic support or other interventions. For flexible flatfoot in otherwise healthy people, and for general injury-prevention or performance goals, the consensus across the studies referenced here is more consistently favorable: gradual, progressive loading of the intrinsic foot muscles is low-risk and shows a reasonable body of supporting evidence, even though sample sizes in individual trials are often modest and more large-scale research would help confirm optimal dosing.

The practical takeaway clinicians tend to repeat is consistency over intensity. Ten minutes of foot-focused work most days, done with attention to form, appears to matter more than occasional long sessions, and pairing exercise with a gradual increase in barefoot or minimal-shoe time seems to produce better results than either strategy alone.

Key Takeaways

Frequently Asked Questions

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