A thicker insert can alter the shoe’s heel-to-toe drop, which is the height difference between the heel and forefoot. That change may affect how the ankle, calf, and Achilles tendon are loaded during a stride, although the response varies from person to person.
Test the new footbed during a short walk before using it for an easy run. Increase exposure gradually and record what happens afterward. New calf tightness, arch soreness, rubbing, or tingling suggests that the shoe, insert, or transition needs another look.
