How to Strengthen Your Ankles Step 1 WALK ON YOUR TOES: Walking on your toes will strengthen the back of your ankle as well as your calf. This is something that you are probably not used to doing. Take it very slow and build up slowly. Step 2 WALK ON YOUR HEELS: Walking on your heels will work the apposing muscles as step #1, the front of your ankle and you shins. This is another exercise that is not common, and should also be taken slow. Step 3 WRITE THE ALPHABET WITH YOUR TOES: Sit down in a comfortable position. Holding your foot at least a few inches off the floor, spell out the alphabet with your big toe, one foot at a time. This will strengthen, stretch, and move your ankle in a wide range of angles. This may seem elementary, but only do it once and see how you feel the next day. As with any new exercise, take it slow. Step 4 STRETCH: After the muscles are warm, it is always good to stretch. First, pull your toes toward you. If you can't reach your toes, use an old tie or belt to assist you. Next, stand and support your weight (lean against a wall or chair) stretch the front of your foot and lower leg by pointing your toes behind you like you are dragging the top of your toes on the ground.

I am guessing because you asked this in dance, that you are a dancer. To help strengthen your ankles do releves and eleves at the barre. I agree with the other answer of writing the alphabet with your foot in the air. You can also purchase a Theraband at a dance supply store. You place the band under your foot and hold both ends as you point and flex your foot. The sales person will show you how to do it correctly.It will not only strengthen you ankles, it will improve your arch as well.