Key takeaways
- Flat feet change weight distribution, and the strain travels to knees and hips.
- Overpronation is the usual mechanism behind the discomfort.
- There are four types, and they need different levels of support.
- Stability and firm arch support matter more than cushioning.
Flat feet, or fallen arches, describe a foot where the natural arch is absent or much lower than usual. Instead of the arch acting as a spring, the whole sole makes contact with the ground, which changes how weight moves through the foot.
The consequences are rarely confined to the foot. Overpronation, the excessive inward roll that usually accompanies flat feet, puts stress on the ankles, knees, hips, and lower back. That chain is why a foot problem often presents as a knee complaint.
Five things cause flat feet
- Genetics. Family history is the strongest predictor, and flat feet run in families.
- Injury. Damage to the tendons or bones supporting the arch, including fractures and tendon tears, weakens the structure.
- Age. The ligaments and tendons holding the arch stretch over time, particularly in older adults.
- Weight. Extra load flattens the arch gradually.
- Medical conditions. Arthritis, diabetes, and some neurological disorders weaken the tissues that maintain the arch.
Four types, needing different things
Flexible flat feet are the most common
The arch is visible sitting and flattens when you stand. This type usually starts in childhood, often causes no pain, and responds well to supportive shoes with proper arch support.
Rigid flat feet stay flat
No arch appears whether standing or sitting. This type is more severe and more likely to cause pain or stiffness, and it needs enhanced support and cushioning.
Adult-acquired flat feet develop over time
Aging, injury, or posterior tibial tendon dysfunction flattens an arch that used to be there. This type often calls for custom orthotics.
Vertical talus is rare and congenital
An abnormally positioned talus bone produces a flat appearance from birth. This is a medical matter rather than a footwear one.
What to look for in a shoe
- Built-in arch support that distributes weight evenly and limits overpronation.
- Stability, meaning a firm midsole and a supportive heel counter that hold the foot aligned.
- Cushioning that absorbs impact without collapsing under the arch.
Orthotic insoles, custom or over the counter, add arch support to shoes you already own and are usually the cheaper first step.
See our insoles and orthotics →
Exercises that support the arch
- Toe curls. Place a towel on the floor and scrunch it toward you with your toes.
- Arch rolls. A tennis ball or massage roller under the foot stretches and relaxes the arch.
- Calf stretch. One leg behind the other, lean forward and feel the stretch in the back calf.
- Plantar stretch. Sitting, pull your toes toward you to stretch the bottom of the foot.
When to see a specialist
Persistent pain warrants a podiatrist or physical therapist, who can identify the specific weakness and recommend orthotics or targeted treatment. Rigid and adult-acquired flat feet in particular are worth having assessed rather than self-managing.
Running with flat feet has its own considerations, which we cover in our guide for runners and in our shoe recommendations.
