The single-arm cable push-down is a single-joint isolation movement that develops the triceps muscle one arm at a time. Because the action is purely at the elbow joint, it is difficult to use any substantial weight. Reps are usually high, such as 8-12 reps per set or more, with a focus on strict form and feeling the mind-muscle connection.
Allows you to focus on one arm at a time
The cable encourages continuous tension throughout the exercise
Builds bigger and stronger triceps, particularly the lateral head