531 is a popular and proven barbell strength training methodology developed by Jim Wendler, an elite powerlifter and long-time strength coach. This is a high-volume (i.e. lots of work) variation of 5/3/1 designed to pack on muscle mass. The routine focuses on compound lifts like the squat, bench press, deadlift, and pullup to build full-body muscle and strength. Anyone can do this routine, but it's not recommended for people who are trying to lose weight since your meal plan may not provide enough nutrition for you to recover from the taxing workouts.