Start: (A) Kneel on the ground with a stability ball about 12 inches in front of knees, arms extended in front of body with palms flat on ball.
Move: (B) Slowly roll ball away from body so forearms are on top of the ball while simultaneously lifting knees off the ground to form a modified plank (body weight held between forearms and toes). Contract abs, and do not allow hips to drop or back to arch. Hold for two counts, slowly lower knees to floor, and roll ball back to start position.
Repeat: Perform two sets of 10 to 12 reps with one minute of rest between sets.