This exercise not only helps with balance and stability but also develops the strength of your hamstrings. You can work your gluteal muscles if you use the third variation.

1 Stand tall and hold on to the support with both hands, place the foot and ankle of the leg to be exercised into the support strap and raise that leg slightly off the group. Flex your standing leg slightly at the knee. Your legs should be parallel to each other and your abdominal muscles pulled in - but not so tightly that your breathing is affected. 

2 Exhale and slowly pull your ankle up toward your bottom, keeping your hips and knees in line with each other. Do not allow your ankle to travel backward.

3 When your ankle has moved as far as it can, inhale and slowly lower your leg back to the starting position - but do not allow your foot to touch the floor.

4 Repeat for desired number of repetitions, then repeat the exercise using your other leg.