You take your shoe off after a run and the insole has crept forward, folded at the toe, or curled up at the heel. It is a common problem, and it usually has one of four causes. The fix depends on which one you have.
First: is it the insole or the sock?
These feel similar from inside the shoe, so check before fixing the wrong thing.
- Insole moving: pull the shoe off. If the insole has shifted or folded, the insole is sliding against the shoe.
- Sock moving: the insole is where it should be, but your sock has bunched, twisted or slid down. That is sock against insole.
- Foot moving: both are in place, but your toes are hitting the front. That is the foot sliding inside the sock and shoe. See why your feet slide forward in running shoes.
Most people have a bit of all three. Fix the biggest one first.
The four reasons an insole slides
1. It is not the right size for the shoe. Aftermarket insoles are often cut for a range of sizes. A few millimetres short at the heel gives it room to travel forward every time you land.
2. It was never fixed in place. Most running shoe insoles are loose by design so you can swap them. Many have a light tack of glue from the factory that gives up after a few wet runs.
3. Moisture. In Singapore, the inside of your shoe is wet within twenty minutes. A wet insole on a wet midsole slides more easily than a dry one, which is why it gets worse on long or hot runs.
4. Your foot is pushing it. If your foot slides forward on every downhill or push-off, it drags the insole with it. Fixing the foot movement often fixes the insole.
Fixes, matched to the cause
Wrong size or shape: trim aftermarket insoles using the original as a template, or go back to the shoe's own insole. It should sit flat from heel cup to toe without curling at either end.
Loose insole: a small strip of double-sided carpet tape or a couple of hook-and-loop dots under the heel hold it without making it permanent. Keep it to the heel; tape under the forefoot can create a ridge.
Moisture: let shoes dry fully between runs, insoles out. Rotating two pairs helps more than people expect in this climate. Synthetic socks move sweat away from the foot instead of soaking the insole.
Foot pushing it: this is a lacing and fit problem. A heel lock (runner's loop) through the top eyelets holds the heel back and stops the foot sliding forward on every stride. Check your size too β a shoe that is too long gives the foot room to travel.
Where socks come in
Be clear about what a grip sock does and does not do here. Grip on the sole holds the sock to the insole, so the sock stops twisting and bunching and the foot moves less inside the shoe. It does not glue the insole to the shoe. If your insole is sliding against the midsole, fix that with the steps above.
What grip socks change is the third case β a foot dragging the insole forward. When the sock holds against the insole and the foot holds inside the sock, there is less movement to pass on. More detail in are grip socks good for running.
Frequently Asked Questions
Why does my insole keep moving in my running shoes?
Usually a combination of a loose or wrongly sized insole, moisture between insole and midsole, and your foot sliding forward and dragging it. Check which one is happening before fixing.
Should I glue my insoles down?
Light double-sided tape or hook-and-loop dots at the heel is enough and stays removable. Permanent glue makes the shoe harder to dry and the insole impossible to swap.
Why do my shoes eat my socks?
The cuff sits below the shoe collar or the heel pocket sits too low, so every stride drags the sock down. See how to stop socks slipping down.
Do thicker socks stop insoles sliding?
Not really. Thickness fills space, which can help a slightly long shoe, but a thick wet sock slides as easily as a thin one. Fit and grip matter more.