How many calories are burned from doing P90X ab ripper X workout?

While the Ab Ripper X certainly burns some calories (as any physical activity will do), it really isn't a significant calorie burner. It only lasts about 15 minutes, but will work your abs pretty hard. The real calorie-burners in the P90x program are the Plyometrics, Cardio X, and Kenpo X. Plyometrics will burn the most by far, but is much tougher than the other two to complete. The best way to lose calories in the long run is to do the whole program, as the strengthening videos will help increase muscle-mass and improve your metabolism. However, if you are just looking for good calorie-burning exercises without the muscle, those three are good videos.  more