The supine leg series focusing on the hamstrings is performed as a difficult superset (doing one exercise right after each other with a long 60 second rest only after all three exercises in the series are completed). Reps are kept the same for the arm and core series except for the progression of the TRX Suspended Crunch to Body Saw. Start this progression on your forearms for the first set, stabilizing the body and raising the hips. Rock your body back and during the forward motion bring your knees under body into a suspended crunch. Try the second set from your hands in a push-up position.