Step by step instructions
Grab a dumbbell with right hand and lie on back on a Swiss ball. Raise hips so that body forms a straight line from knees to shoulders. Hold the dumbbell at chest and draw shoulder blades down and together.
Press the weight straight up and then lower back down to the chest. Nothing but your arm should move. Complete the prescribed number of reps with right hand and then repeat on the left to complete one set.