Over the last 2 years I have broken bones in both of my feet from over-use and consequently have had them in wlking boots which imobilise the ankle. This weakened all the stabiliser muscles in my ankles so to strengthen them my physio gave me the following exercises which may be useful for you:
- stand on one foot for 30 seconds without holding onto anything. Alternate feet.
- calf raises. To begin with do them on a flat surface and build up to doing them over a step so that you are going through a greater range of motion.
- use a thera band to do plantarflexion, dorsiflexion, inversion and eversion against resistance.
Hope that helps!