Single-Arm Reverse-Grip Pushdown

Attach a single-arm handle to the high pulley of a cable station. Grab the handle underhand with your left hand and pull it down until your elbow is bent 90 degrees. Stand straight with your upper arm tucked against your side. Your feet should be hip-width apart, knees slightly bent.
 
Push the handle down until your arm is straight, while keeping the rest of your body in the starting position.
 
Pause, then slowly allow the handle to rise until your elbow is bent at 90 degrees.