Equipment
Pullup Bar
Body Parts
Core

Photo credits: Top, James Michelfeder; Step 1, James Michelfelder; Step 2, Steer Digital Media.

Step-by-step instructions

1. Hang from a bar overhead, pulling down with your lats—think about "shortening your armpits"—so you’re engaging your shoulders and not just hanging out of your arm sockets. Squeeze your abs to bring your toes up toward the bar in a pike position.
2. Slowly, with control from your obliques, move your legs side-to-side, holding them together like they’re one windshield wiper. Only lower to one side as far as you can control without twisting your hips—or losing your hold entirely.