For most people, flat feet are not bad. They’re an extremely common structural variation, and the majority of people with low or absent arches go through life without any pain or functional problems. All children are born with flat feet, and while most develop an arch during the first decade of life, plenty of adults simply never do. Flat feet only become a medical concern when they cause symptoms or lead to problems elsewhere in the body.
Flexible vs. Rigid Flat Feet
The distinction that matters most is whether your flat feet are flexible or rigid. If you stand on your toes and an arch appears, you have flexible flat feet. This is the common, usually harmless type. The arch is structurally there but collapses under your body weight. It doesn’t require imaging or treatment unless it’s causing pain.
Rigid flat feet are different. If standing on your toes doesn’t produce an arch, and you can’t see one even when your foot isn’t bearing weight, that’s a sign of an underlying structural problem. Rigid flat feet can result from conditions like tarsal coalition (bones in the foot fusing together), inflammatory arthritis, or neurological disorders. This type is more likely to need medical evaluation and treatment.
The U.S. military draws this same line. Current Department of Defense medical standards disqualify recruits with rigid or symptomatic flat feet, but flexible, painless flat feet are not a barrier to service.
When Flat Feet Cause Problems
Flat feet become a genuine concern when they’re symptomatic. Pain can show up in several places: along the inner ankle (where the posterior tibial tendon runs), in the heel, across the bottom of the foot, or in the outer part of the rearfoot. Some people develop bunions or hammertoes over time. If the pain is bad enough, it can change the way you walk.
The bigger issue is what happens up the chain. When the arch collapses, the foot rolls inward (overpronation), which forces the shinbone to rotate internally. That rotation pushes the knee inward into a knock-kneed position and internally rotates the hip. Over time, this chain reaction can shift pelvic alignment and destabilize the lower back. Research on young women with flat feet found measurable effects on balance, agility, and core muscle engagement, all stemming from this altered alignment.
This doesn’t mean flat feet will inevitably wreck your knees or back. It means that if you have flat feet and you’re experiencing knee pain, hip pain, or lower back issues, your foot structure could be a contributing factor worth investigating.
Flat Feet in Children
If your child has flat feet, there’s almost certainly no reason to worry. Every child is born with flexible flat feet, and the arch develops gradually over roughly the first ten years of life. A flat-footed toddler or even a flat-footed seven-year-old is completely normal. Treatment in children is only considered when there’s pain, stiffness, or signs of a rigid deformity.
Orthotics, Exercises, or Both
If flat feet are causing you trouble, the two main conservative approaches are arch supports (orthotics) and foot-strengthening exercises. Both work, and combining them appears to produce the best results.
Orthotics provide immediate structural support. A systematic review found they reduce the overall risk of lower-body injuries by 28% and lower-leg stress fractures by 41%. One practical finding: prefabricated insoles performed just as well as expensive custom-molded orthotics for preventing overuse injuries and treating plantar fasciitis in normally active adults. So you don’t necessarily need the pricey option.
Strengthening the small muscles inside the foot offers a different kind of benefit. Four to eight weeks of targeted exercises has been shown to change static foot alignment (essentially rebuilding some arch support from within), increase the size and force output of those muscles, and improve dynamic foot function during running and jumping. These exercises include things like towel scrunches, marble pickups, and “short foot” exercises where you try to shorten your foot by drawing the ball of the foot toward the heel without curling your toes.
The research suggests these approaches complement each other rather than compete. Orthotics support the foot passively while strengthening builds active, muscular support. Using both together has been associated with greater reductions in pain than either strategy alone.
Choosing the Right Shoes
If you have flat feet and overpronate, motion control shoes are designed for you. They feature a reinforced heel counter and a denser midsole to limit excess inward rolling. Stability shoes offer a moderate version of the same concept. Neutral cushioning shoes, on the other hand, are built for people whose feet roll outward, so they’re generally the wrong choice for flat-footed runners.
That said, shoe choice matters most if you’re active. If you’re walking around an office, the difference between shoe categories is much less significant than simply wearing something supportive rather than completely flat.
When Surgery Becomes Necessary
Surgery for flat feet is uncommon and reserved for cases where conservative treatment has failed and the condition is progressing. The most common scenario in adults is posterior tibial tendon dysfunction, a degenerative condition where the tendon that supports the arch gradually weakens and lengthens. This progresses through stages, starting with pain and swelling along the inner ankle, advancing to a visible flexible deformity, and eventually becoming a rigid, fixed deformity.
Surgical options depend on the stage and can include repositioning the heel bone, lengthening the outer column of the foot, or transferring a nearby tendon to take over the job of the failing one. Recovery from these procedures typically involves weeks of non-weight-bearing followed by months of rehabilitation. It’s a significant undertaking, which is why it’s a last resort after orthotics, physical therapy, and activity modification have been given a fair trial.