If you're a young guy who hasn't trained much before, doing exercises that only move your elbow (like lying triceps presses) makes your triceps muscle grow way more than doing exercises like bench presses that use multiple joints at once.

If you're a young guy who hasn't trained much before, doing exercises like the bench press will make the back part of your triceps grow way more than just doing arm-only exercises like lying triceps extensions.

If you're a guy who hasn't trained much before, your triceps muscle in the back of your arm grows about the same no matter if you do push-ups, triceps extensions, or a mix of both — the type of exercise doesn't really matter for this part of the muscle.

When you do triceps exercises with your arm stretched overhead instead of at your side, your triceps muscle grows more—even if you’re lifting lighter weights.

Overall, your whole triceps muscle grows more when you do the exercise with your arm overhead—even if you’re not lifting as heavy.

If you're a guy who's new to lifting and you do both big compound moves and isolated triceps exercises, your triceps will grow more than if you only do one type — not because the exercises add up, but because they hit different parts of the muscle in different ways.