heavy weight lifting 3 times a week is much more effective in terms of body composition
sure, even Tony admits lifting weights builds bigger muscles, but it won't get you in better
cardio or athletic shape - unless you train in a circuit style method.. I guess similar to how Milos
does it.
With P90X, there's no reason to get on a bike or treadmill. If you do the program properly, you are
well into your aerobic and even anareobic zones for most of the hour long workout.
I finished the program back in Mid-April. I lost about 8 lbs. I got leaner, but I was much harder.
I'm back to lifting heavy and I'm looking to add on at least 5lbs of muscle before trying it again.
as for the weights, they don't have to be light per se. You determine how many reps you want to do ahead of time, 6-8, 8-10, 12-15, so the weight can be moderately heavy, although you may need to save some in the tank, because you may be doing it again in another round, and you don't want to burn yourself out. It's not a bbing program for sure - unless you're just starting out, but you can get fitter with it.