P90X2 differs from P90X in several ways. Muscle Confusion is still the key, but Tony and company have given you more independence with when to change Phases. In P90X2, there is the Foundation Phase, the Strength Phase, and the Performance Phase. Tony suggests 3 to 6 weeks in each of the first two phases and 3 to 4 in the last phase.
You don’t need to perfect each routine before moving on. Let’s face it, that would take longer than six weeks anyway and you want to keep your muscles confused. I spent four weeks in the Foundation Phase. Could I have used more time in this phase? Of course, but I was anxious to get on to the next phase – it is called Strength after all.
I just finished Chest, Back and Balance for week 5 in Phase 2. I decided that I am ready to move on after this week. Have I mastered Phase 2? Of course not. I am also confident that I would continue to get benefits from the routines in Phase 2. But I am ready for Phase 3. Plus I filled up my worksheet. Nothing says “been there and got the T-shirt” like a full worksheet.
I really enjoy P90X2 and I am sure I will do it again. Maybe after a round of Insanity. (Shaun T has made me cry uncle once, but I feeling confident today.) So it’s not like I won’t see Chest, Back and Balance again. By the time I do, I am sure it will confuse my muscles all over again.