Bend at the knees, then jump and reach for the ceiling with arms extended. Repeat as a catchy song echoes through the gym.

A 30-minute weekend fitness class for Penn State dance marathon participants was just a tiny preview of the grueling 46-hour event for charity that starts Friday. The Penn State IFC/Panhellenic Dance Marathon is billed as the largest student-run philanthropy in the world. For the first time, workouts were offered for the more than 700 participants to get in shape for the annual epic affair.

The two-steppers are urged to lay off caffeine and alcohol and to get eight hours of sleep a night leading up the weekend. Organizers say fitness is important, too, and hope the new class helps get dancers prepared.