Hang from a pull-up bar and raise your legs to vertical (or set up on the floor for the lower tiers). Keeping your legs together, sweep them side to side in a controlled arc like a windshield wiper. Repeat for max reps.

Declare your tier before starting. One rep = a full sweep from one side to the other, under control, legs together. No swinging or using momentum. Most reps at your tier wins; a higher tier always outranks a lower one.

Difficulty tier + repetitions