The reverse-grip pushdown is an isolation, single-joint move, which isolates the triceps without the assistance of other muscle groups or joints. Underhand grip places more stress on the medial head of the triceps. Since it helps target one of the heads specifically, it’s important that you incorporate it into your routine, if not every workout, for balanced development.
Using cables aims to maintain constant tension on target muscles important for muscle hypertrophy. This continuous resistance makes it a more beneficial method for muscle gain. Using cables can be both effective and easier for beginners. You can get the best results in this exercise with light to medium weights and medium to high repetitions.