I really started breaking down toward the end, and barely finished. I saw benefits, but I felt like they had plateued over the last few weeks. I dunno, maybe I just wasn't pushing hard enough at that point. Since I experienced improvements in strength, flexibility and overall well-being I wouldn't recommend against P90x - but if I had it to do all over again I might have tried to shed a few pounds first by doing something more basic like running or cycling for a few weeks before starting the program.