HOW: Place the swissball against a wall. Make sure to have a sturdy chair or step. While in a seated, upright position, push into the ball with your foot flat on the ball. There should be a bend in your knee as you push in the ball. As you push, you shouldn’t be moving at all but you will feel your muscles activating.
FEEL: You should feel the muscles in the back and front of your thigh working. You should also feel your glutes working.
COMPENSATION: Don’t slouch your back, stay upright.