You will need two Swiss balls. Bring both balls together, side by side. Place one of your lower arms on each ball. Your body should be approximately at a 45 degree angle with normal curvature of your lower back.
Roll the balls outward, allowing your arms to open up. Continue until you feel you have reached a comfortable range of motion. Squeeze your arms back together, bringing the balls back to their original position. Try doing 2 sets with 10-12 repetitions.
Keep your spine in a neutral position.
Muscles Worked: Chest