This is truly a double-duty exercise. It serves two purposes. It builds explosiveness on the concentric (pulling) portion of a chin-up because each rep is re-set at the bottom of the movement.
It also takes you from single-chinner to multiple-chinner. This could be the result of increased grip strength and scapular retraction, which becomes a necessity since there's no need to swing, hump, or kip your way up.
related posts
Tip: The Dumbbell Hip Thrust
Most people do hip thrusts for glute strength, but they can also be used as a high-rep finisher. Bonus: It's a quick setup with a dumbbell.
100 Workouts From Ripped City
How to get truly ripped without losing muscle mass.
Tip: The Power Exercise for Delts and Traps
Take a bodybuilding exercise, mix in an athletic movement and what do you get? A new way to add size to your shoulders and traps.
Do You Really Need a Lifting Belt?
If, when, and how to wear weight belts to get bigger and stronger. Four coaches weigh in.