Position
Stand with your feet about shoulder-width apart. Lean forward, keeping your weight over your ankles. Maintain a natural arch in your lower back. Place one hand on your hip and the other on top of the bar, just outside shoulder-width. Pull you elbow back, aligning your upper arm directly with the cable. Begin with your elbow pointed back and tight against the side of your body.

Technique
Slowly let the resistance pull your lower arm up and out in front of your body. Continue to let your lower arm come up to about a 90-degree angle, keeping your upper arm firmly in position. Hold, relax your hand, and contract your triceps. Maintaining your upper arm in position, slowly pull your lower arm back to its start position. Repeat.