The reverse-grip cable straight-bar push-down is a twist on the popular cable straight-bar push-down. The difference has to do with how the hands are positioned holding the bar: the palms facing up rather than down. Because grip will be a limiting factor, this movement is usually performed for moderate to high reps, such as 8-12 reps per set or higher.
Great burnout movement for triceps
Underhand grip places more stress on the medial head of the triceps