Sit on the chair, square your pelvis and your torso.
Place the balance cushion in front of the chair and put the SMR on the cushion.
Place one foot on the roller.
Keep your knees in line with your toes

1. Roll the SMR forward until it stays on the cushion.
2. Roll it back by pulling your foot to you until it stays on the cushion.

Find the limits of the movement.