You must keep your ankles strong so they don't turn over in your favorite high heels, and a balance ball can help. Also called a BOSU ball, meaning "both sides up," this ball looks like a standard exercise ball that's been cut in half. You can lay it flat and balance on the soft, squishy side, or turn it upside down so the dome is on the ground and you have to balance on the flat side. Both sides help give your ankles more strength and stability.
No need to start out with mega-hard exercises -- stick to the basics when you start to train your ankles. Turn the balance ball so the flat side is down, then step up onto the domed top. It feels a bit awkward at first, so stay close to a wall to help you balance. Stand up straight and let go of the wall when you can, tightening your abdominals to help you stay balanced. The ball makes an unstable surface, making you constantly shift your weight a tiny bit. Many of these weight shifts happen in your ankles, as you lift or lower your toes to keep your balance.
Making It Harder
Think you've mastered the basic balancing technique? Try moving your feet on purpose by pointing and flexing your toes. This shifts your body weight on the ball, requiring your ankles to adjust for changes in the different ball areas. Or, lift one knee and try to balance on one leg at a time to focus the strengthening on one ankle. Bend your knees slightly and straighten one leg to tap on the floor in front, to the side and behind the ball, keeping the other foot as still as possible on the balance ball.
Any kind of body movement is going to disrupt your delicate balance on top of the ball, which means your ankles must work harder to keep your feet in place. This doesn't just mean front and back -- your ankles must adjust for sideways movement as well. Try performing three-sided squats by lowering your body straight down, with your hips back, then standing up. Squat again but turn your upper body to the left. Squat in the middle, then turn your upper body to the right on the next squat. These changes in your center of gravity help keep the muscles on the sides of your ankles strong.
Although you might feel like you need an act in the circus when you first step on the balance ball when it's dome-side down, the different balancing position works all sides of your ankles. Step up and point your toes so the rim of the flat section touches the floor, then rotate your ankles to lower the rim in a circle all the way around the ball. Go both ways to work a full range of motion in both ankles. To concentrate on the front and back of your ankle, point your toes to push the front of the ball down, then push back through your heels to lower the back of the ball.