P90x or the alternative workout

Okay....I'm hearing all this stuff about P90x and after reviewing it and knowing I'm in sub-par shape, I probably know that I will develop some type of injury if I went with P90x. How do I know I'm in Sub-par shape? I just experienced the Toddler workout (over the course of a few days)
1) Just have a clingy toddler that wants to be held isometrically with your biceps while you stand in lines at Disneyland. Don't forget that you also work your triceps as you slowly, yet carefully put her down to prevent from any injury.
2) Work cardio and gluts by placing child in a stroller and walking briskly.
3) Work core musculature by pretending to be some type of merry go round holding onto toddler tightly while you go in circles.
4) Work calf musculature while ambulating over sandy beach, work out pectoralis & core musculature while carrying all the beach equipment at the same time to save a trip to the car.
5) Work your pectoralis musculature, back extensors, core muscles while ensuring your wiggly child sits safely in aerial tramway at the San Diego zoo.
6) Bonus workout: Workout 2nd digit finger extensor muscle (index finger) as you say "shhhhh!"

Result= Strain & soreness! ;)