Flat Feet: What They Are, and Whether They Matter

A low or absent arch is common. Estimates vary widely with how it is measured, but a substantial minority of adults have flat feet, and most of them have no symptoms and never will.

The advice given about it is frequently more confident than the evidence supports.

What a flat foot is

The arch is formed by the shape and arrangement of the bones, supported by ligaments and by the muscles within the foot and lower leg. Some people have a low arch structurally. Others have a flexible flat foot. An arch that appears when the foot is unloaded or when standing on tiptoe, and flattens when weight is applied.

The distinction matters. A flexible flat foot has muscles and tissue that can influence it. A rigid one is largely a matter of bone shape and is not going to change.

There is also the question of how much the foot rolls inward when you walk or run. Some inward roll is normal and is part of how the foot absorbs load. The idea that it should be prevented has not held up well.

What the evidence says about it causing problems

Less than you would expect from the confidence of the advice.

Studies looking for associations between flat feet and injury in general populations find weak and inconsistent relationships. Military recruit studies, which are one of the few settings where large numbers of people do identical activity, have generally not found flat feet to be a strong predictor of injury.

The evidence for prescribing arch supports to people without symptoms, on the basis of foot shape alone, is not good.

So: if your feet are flat and nothing hurts, there is no problem to solve.

When it does matter

If you have symptoms. Arch pain, heel pain, inner ankle pain, or pain that appears with standing or walking distance. Then the foot shape is part of a picture worth assessing properly.

If it changed. An arch that was there and has flattened, particularly in one foot, particularly in an adult, is worth seeing someone about. Progressive adult flat foot has a specific cause and responds to being caught early.

If standing all day is uncomfortable. Not because flat feet are wrong, but because sustained standing is demanding for any foot and a low arch may mean the supporting structures are working harder.

What strengthening achieves

For a flexible flat foot, foot strengthening does improve the muscles that support the arch, and there is reasonable evidence it helps with symptoms in people who have them. Whether it changes the visible arch height much is less clear, and it matters less than whether the foot is comfortable.

Short foot exercise. Foot flat, draw the ball of the foot gently toward the heel without curling the toes, so the arch lifts slightly. Hold a few seconds, repeat. This is the main one and it is commonly done wrong.

Heel raises, slowly, both feet then single leg. Up over two seconds, down over three.

Big toe control. Lifting the big toe alone, then the other four alone.

Single-leg balance, barefoot, which asks the whole system to work.

Insoles

Reasonable if you have symptoms and they help. Not indicated simply because your arch is low. If they make standing days more comfortable, that is a good enough reason to use them, and using them does not weaken your feet in the way sometimes claimed.

Where a teacher helps

Short foot work is the one exercise here that people almost always perform incorrectly, curling the toes instead of lifting the arch. It looks nearly identical and trains something different. Thirty seconds of correction from someone watching fixes it permanently.

Sessions are live on video, thirty or sixty minutes, and feet show up well on camera.

Questions people ask

Are flat feet a problem?

Usually not. A substantial proportion of adults have low arches and no symptoms, and studies looking for links between foot shape and injury find weak and inconsistent associations. If nothing hurts, there is nothing to fix.

Can exercise give me an arch?

For a flexible flat foot, strengthening improves the muscles supporting the arch and can help symptoms. Whether it noticeably changes arch height is less certain, and comfort matters more than appearance.

Do I need orthotics?

If you have symptoms and they help, they are reasonable. Prescribing them purely because an arch is low is not well supported. Using them does not weaken the foot in the way sometimes claimed.

When should I see someone about my feet?

If you have arch, heel or inner ankle pain, if standing is becoming painful, or if an arch that used to be there has flattened, particularly in one foot in adulthood. That last one is worth attention sooner rather than later.