RE: Power90x
The regular rotation has you do 6 different workouts in a week(let's see if I can get it right from memory: 1) chest/back; 2) plyometrics; 3) shoulder/arms; 4) kenpo; 5) legs and back; 6) yoga; 7) day off or stretch. You follow this for 3 weeks, then you have a recovery week, where you emphasis the core and stretching with core synergistics, yoga and kenpo (maybe another?). Then you get back into the heavier work, with a different rotation for three weeks(chest/shoulders/triceps, back/biceps, etc.).
The rotation is meant to be periodized (alternating heavy and lighter work) so that your body doesn't adapt, has ample recovery, and is ready to make new gains with each new cycle.
There are other rotations other than the regular one, including a lean rotation, which emphasizes cardio more, and a "doubles" which adds an extra cardio workout to each day.
I wouldn't worry about not working out all areas enough!!