Attach a long straight-bar attachment to the high cable on a cable crossover station. Lower the pulley so that the bar hangs about 4-6 inches above your waist. Stand with the bar behind you and place your hands on the bar with an overhand grip and spaced about shoulder width apart. Straighten your arms completely and maintain straight arms throughout the exercise. Allow the bar to rise as high as possible behind you while maintaining straight arms. Contract your lower traps to pull your shoulder blades down for a second as you focus on contracting your lower traps as much as possible. Then allow the bar and your shoulder blades to rise back up to the start position and repeat for reps.