A chin up is a variant of a pull up where your forearms are supinated, allowing you to grab the bar with an undergrip. The main muscle working here is still the latissimus dorsi, and it's still a compound exercise which uses a lot of helper muscles, but there are two key differences. Firstly, in a chin up, your biceps and brachialis are perfectly aligned with the line of grip tension, which allows them to engage really hard and help the movement. Secondly, because the elbows are in front of your

How to Build Bigger Forearms Fast | Skinny Arms Fix

GET MASSIVE FOREARMS FAST! 💪 | 5 Best Exercises 🥈 DAY 1 vs DAY 10 Forearm 🚀

5 Forearm Exercises That Build 3x More Strength Than Wrist Curls