Once isometric exercises have been mastered, you can move on to isotonic exercises, which involve improving the range of motion of the ankle against resistance. Isotonic exercises can be performed using a resistance band, which you can get through your physical therapist or at any sporting goods store.
Using a resistance band around your forefoot, hold the ends of the band with your hand and gently push your ankle down as far as you can and then back to the starting position. Repeat 10 times.
Next, tie the resistance band around a fixed object and wrap the ends around your forefoot. Start with your foot pointing down and pull your ankle up as far as you can. Return to the starting position and repeat 10 times.
Now, tie the ends of the band around an object to the outer side of your ankle. Start with the foot relaxed and then move your ankle down and in. Return to the relaxed position and repeat 10 times.
Finally, tie the ends of the band around an object to the inside of your ankle and hold your foot relaxed. Bring your foot up and out and then back to the resting position. Repeat 10 times.