Leg Curls on the Ball
Leg Curls on the ball:
This is a great exercise for your hamstrings (the posterior thigh) and calves (posterior lower leg) and core.
Put your heels on the ball and lift your hips. If you can balance like that, go ahead and pull the ball into your body as far as it will go. then return the ball to the starting position and repeat.
Good luck and have fun
Live Good Fitness