flatfeet:
No treatment is necessary for flatfeet if they don't cause pain.
Therapy
If your flatfeet are painful, your doctor might suggest:
Arch supports (orthotic devices): Over-the-counter arch supports may help relieve the pain caused by flatfeet. Or your doctor might suggest custom-designed arch supports, which are molded to the contours of your feet. Arch supports won't cure flatfeet, but they often reduce symptoms.
Stretching exercises: Some people with flatfeet also have a shortened Achilles tendon. Exercises to stretch this tendon may help.
Supportive shoes: A structurally supportive shoe might be more comfortable than sandals or shoes with minimal support.
Physical therapy:
Flatfeet may contribute to overuse injuries in some runners. A physical therapist can do a video analysis of how you run to help you improve your form and technique