What is the reason why insoles always retract?

This is because the friction between insoles and shoes is small, which can be improved by the following methods:

① As long as a piece of 3.3 cm square hard cloth is sewn in the middle of the insole, it can prevent the insole from coming out.

(2) If the insole is thick in winter, you can find a piece of linen or tarpaulin, cut it into a half-moon shape, with one side straight and the other side bent, and sew one side of the curve on the front end of the insole to make it look like slippers. The insole won't run backwards if you hold it with your toes. The size of the cloth should be comfortable to wear.