Each workout has four versions based on total time (30 or 45 minutes) and interval length (20, 30, or 45 seconds): 1) 30 minutes with 20-second intervals (S 30), 2) 45 minutes with 20-second intervals (S 45), 3) 30 minutes with 30-second intervals (L 30), and 4) 45 minutes with 45-second intervals (L 45). The 'S' stands for short interval and the 'L' stands for long interval. Each workout except Reformer has a 30 and 45 minute version without rests ('C' for continuous).