HOW: Get a swiss ball ideally set-up between a wall and your back, have it initially placed in your low back region near waist height. While keeping pressure into the ball and the ball, perform a squat and repeat.
FEEL: You will feel your leg muscles, especially quads and glutes working with this exercise.
COMPENSATION: Do not lose ideal squat form technique, do not let your knees collapse in or bow out, do not lose pressure into the ball into the wall.