Hypertrophy, is a study of what causes muscles to grow. I can sum this up to 3 rules of thumb. First, it stresses frequent workouts; the key is to work muscle group at least twice per week with at least 48 hours rest before retraining the muscle group. Second, you must gradually increase the weight of your exercises. Thirdly, you must eat more than you currently do, the extra calories and protein are necessary if you want to gain muscle mass. Without an increase in your caloric intake your body does not have the fuel it needs to grow.
http://www.hypertrophy-specific.com/hst_index.html
I like the hypertrophjy specific training too. Its hard to do those total body workouts, so instead I try to do every muscle group twice a week. That normally takes 6 workouts though, but you can do a workout in 30-45 mins so thats maybe only 3-4 hrs a week, which is really not that much if you think about it).
Make sure you eat enough protein, do abs, and cardio.
