taken from page 162 from How I Got My Wiggle Back
While standing, attach a Velcro cuff to your foot. Start in full eversion and invert your foot fully. Your leg crosses over and back to the end range of motion. the cable runs across the body. Do not move your shin bone. The lower leg must not not move at all. (no cheating!) By holding it still, the muscles in the foot are isolated.
This exercise develops the muscles that suspend the spring in your foot as well as the hips.
There are variable resistance bands you can use when you want to increase resistance. This exercise should be done barefoot but can be done shod.