◎ Join the millions completing the Zen Challenge Series! ◎ 0 to 20 Pull-ups in 6 weeks! ◎ Featured on Glamour Magazine, Yahoo!’s Appolicious, Popsugar Fitness, Apple’s “What’s Hot”, Apple’s “New & Noteworthy”, and doctor recommended on healthTap! Are you ready for the 20 Pull-Ups Challenge? Train your upper body/core and build up to completing 20 pull-ups with same people that brought you the OFFICIAL #1 5K Training app C25K®. Using a proven program, the 20 Pull Ups Challenge slowly but surely