Adjust the bar at about hip height. This exercise is best done on a non slip surface so your feet don't slip out, or use a heavy dumbbell. Line up so your lower chest is directly under the bar. Tighten your core and get your body into a plank position with a neutral spine. With straight arms, set your shoulders back and down on the body, feeling a pinch in your shoulder blades. Then keeping a neutral spine lift your body all the way to the bar.