off season and P90-X

I've had the P90-X DVD's for a couple years and have never used them, my training schedule was to just too full with all the swimming, biking, and running. After a week of nan off season I've decided to give P90-X a try. I'm 1 week into it and am enjoying it so far, it's kicking my butt! During my workouts my muscles are shaking and I'm hitting muscle failure quickly. I usually wake up a little sore in my legs and so sore in my upper body that it's a struggle to even brush my teeth! I suspect that I'll get very quick gains from doing the P90-X routine because the workouts are so foreign to my body. Anytime someone switches their workouts around it shocks the body and it makes for great results. The no-bulk strength training and the plyometric aspects of the p90-X will help my triathlon racing later in the season.