Step by step instructions
Holding a dumbbell in left hand, come into a side plank with right elbow under shoulder and feet stacked on top of one another. Press hips straight up to the ceiling so body forms a straight line.
Extend left arm in front of you, keeping a slight bend in elbow. Open left arm in an arc out to the side of shoulder. Return to starting position. Do all reps on one side, then switch sides to complete set.