Ive done them and they are tough. Im very fit and had a hard time with a few of them, especially the pullups, they are crazy about their pullups. I usually did the DVDs in my own order and skipped the ones I didnt like. The workouts tone your muscles really well. I use P90X when I need a break from the gym or dont have access to one. I did them for 2 weeks after a bulking phase and toned my new beef very well
