Why Your Shoes Wear Out on the Inside Edge

Set your shoes on a table and look at them from behind. If the heels lean in toward each other and the inner edge of each sole is worn smooth, your feet may roll inward more than average. People often call that overpronation. It's a term people hear a lot, and it's often misunderstood.

This guide explains when rolling in is normal and when it's worth a closer look. We cover the common causes of inner-edge wear and one warning sign that is easy to miss. We also go through what helps, from shoes and exercises to store-bought insoles and custom orthotics.

Rolling In Is Normal, Up to a Point

Every foot rolls inward a little each time it lands. That motion is called pronation, and it is how the foot absorbs the impact of a step. Then the foot rolls back out and stiffens to push off. Cornwall and McPoil (1999) measured this in 153 people as they walked. The rolling in and out happened through the whole foot, as a normal part of every step.

So pronation isn't a defect. The question is whether your feet roll in so far, or for so long, that something gets overworked.

For a lot of people, the answer seems to be no. Nielsen and colleagues (2014) followed 927 new runners for a year. Everyone ran in the same neutral shoe. Runners whose feet rolled in a moderate amount did not get hurt more often than runners with average feet. In fact, that group had fewer injuries for the distance they ran. The authors said more work is needed on feet that roll in a great deal. Another trial found that, in a standard shoe, runners with rolled-in feet got hurt more often than runners with average feet (Malisoux and colleagues, 2016). So the research is mixed.

What Inner-Edge Wear Looks Like

A foot that rolls in more than average tends to leave a few clues on its shoes.

• The heel counter leans inward when you look from behind. The heel counter is the stiff cup around the back of the heel.
• The inner edge of the sole is worn smooth, at the heel, near the big toe, or both.
• The upper bulges over the inner side of the sole.
• The midsole is crushed more on the inside. The midsole is the foam layer under your foot.
• The insole shows a darker print under the arch, where a higher arch would leave a gap.

Why It Happens

Flatter Feet

Foot shape is one likely reason. Flatter feet carry more of their weight on the inner side. Buldt and colleagues (2018) reviewed the studies that measure pressure under the foot. In flatter feet, pressure was higher under the inner arch, the middle of the forefoot and the big toe. The pressure path also ran closer to the inner edge. That may be part of why shoes wear there. In that review, though, foot shape explained only a small part of the differences in pressure.

A flat foot can be flexible or stiff. In a flexible one, the arch shows up when you sit or stand on your toes, and it flattens when you stand. A flexible flat foot that doesn't hurt usually needs nothing more than good shoes.

A Tight Calf

When the calf muscles are tight, the ankle can't bend forward enough as the body passes over the foot. The foot can make up for it by flattening more through the arch. A tight calf is a recognized part of the flat-foot picture (Stellar and colleagues, 2023). Our guide to tight calves shows the stretches we use.

A Tired Tendon on the Inside of the Ankle

This is the one that is easy to miss. The posterior tibial tendon runs behind the bony knob on the inside of the ankle and helps hold up the arch. When it gets inflamed or worn out, the arch can slowly sink on that side. Doctors call this adult-acquired flatfoot.

It often goes unnoticed for a long time. Kohls-Gatzoulis and colleagues (2009) surveyed women over 40 in England and examined the ones with symptoms. Of all the women who answered the survey, about one in thirty had early tendon trouble of this kind. None of them had been diagnosed, even though they'd had symptoms for a long time.

Watch for pain or swelling along the inside of the ankle. Other signs are one foot getting flatter than the other, and trouble rising onto the toes of that foot. One shoe wearing on the inside much more than the other is another clue. Kulig and colleagues (2009) studied 36 adults with early stages of this problem. All of them wore orthotics and stretched, and all three groups improved. The groups that also did strengthening exercises improved more. Our rehab guide for this tendon shows the exercises.

In Children

Many young children have flexible flat feet that never cause trouble. A child who wears through the inner side of their shoes, has pain or tires easily should be checked. One study looked at children whose heels leaned far inward and who wore through their shoes. Simple heel cups improved the wear in most of the children who were followed up (Theologis and colleagues, 1994). Our post on kids' flat feet covers when to worry.

When Inner Wear Matters

Inner-edge wear matters when it comes with pain. Brund and colleagues (2017) measured pressure under the feet of 79 male runners and followed them for a year. The runners who loaded the inner side of the foot more had more Achilles, heel and shin injuries than those who loaded the outer side. The study was small, and the authors called for larger ones.

Pain along the arch or heel, on the inside of the shin, at the Achilles tendon or around the kneecap is worth a look when your shoes wear this way. So is one foot that seems to be flattening more than the other.

What Helps

The Right Shoes

Stability and motion-control shoes are built to limit how far the foot rolls in. They use firmer foam or a raised edge on the inner side. Malisoux and colleagues (2016) gave 372 recreational runners either a standard shoe or a motion-control version of the same shoe. The motion-control shoe lowered the overall injury risk, and the benefit was clear only in runners with flatter, rolled-in feet. A follow-up analysis found fewer of the injuries linked to rolling in, such as Achilles, heel, shin and knee pain (Willems and colleagues, 2021).

Look for a firm heel counter that doesn't fold when you squeeze it. Replace the shoes when the inner edge of the midsole is crushed. A shoe that has collapsed on the inside no longer sits level under your foot. Our guides to everyday athletic shoes for women and for men cover fit.

Exercises

Stretching a tight calf and strengthening the muscles that support the arch are often part of the treatment plan. Our rehab guide for flat feet has a starting routine. Stop any exercise that causes sharp pain, and have a swollen or painful inner ankle examined before you start.

Store-Bought Insoles or Custom Orthotics?

Orthotics don't rebuild an arch, and they don't stop a foot from rolling in. What they do is more modest. Mills and colleagues (2010) pooled the studies on how orthotics change movement. Wedged orthotics cut the amount the heel rolled in by a small amount. In studies of healthy people, molded orthotics clearly lowered the impact of each step.

For flexible flat feet in adults, the evidence for pain relief is limited. A systematic review found no high-level evidence, only lower-level evidence that orthotics ease pain and change how the foot loads (Banwell and colleagues, 2014). For heel pain, store-bought insoles have done about as well as custom ones in trials (Landorf and colleagues, 2006; Whittaker and colleagues, 2018).

That's why we usually start simple. A supportive shoe and a good store-bought insert are a sensible first step for many people with flat feet. A custom functional orthotic makes more sense in these situations.

• Pain keeps coming back even in good shoes with a store-bought insert.
• One foot is flattening more than the other, or the tendon on the inside of the ankle is involved.
• Your foot shape doesn't fit off-the-shelf inserts, such as a very flat foot or feet that differ a lot from each other.
• You need the support to fit into specific shoes for work.

A flat foot that is stiff and painful needs a diagnosis first, and sometimes an X-ray, before any insert. If you have numbness or diabetes, any insert needs a careful fit and close skin checks. If an insert causes new pain, blisters or numbness, stop wearing it and call us. Our guide to how custom orthotics work explains how they're made.

When to See a Podiatrist

Make an appointment if you notice any of these.

• One foot getting flatter than the other, or one shoe wearing on the inside much more.
• Pain or swelling along the inside of the ankle.
• Trouble rising onto the toes of one foot.
• Arch, heel, shin, Achilles or knee pain that keeps coming back.
• A flat foot that is stiff, or a child with flat feet and pain.

Bring the shoes you wear most. Dr. Patish will look at the wear, check the tendon and your arches, and watch you walk. Then he'll recommend what fits, whether that's shoes, exercises, a store-bought insert or a custom orthotic. You can request a visit online. For other wear patterns, see our guide to shoe wear patterns and what they mean. Our post on flat feet in adults covers that topic in depth.