OK, post-mortem on Insanity. What an awesome winter workout after enjoying the excess of the holidays!
The Good: I experienced a noticable improvement in cardiovascular capacity and fast-twitch muscle conditioning. While definitely not trying to lose weight, I did lean out by nearly 10 pounds. Having said that, I continued to eat between 3000-3500 calories a day and losing weight was not a goal.
The "not so good": When I finished the program and got outside in the early AM for running, I noticed a soreness (a bit extreme) the following day and that was my slow twitch muscles screaming from lack of targeted training. It's all good and now I'm back on the Incline: It's only 1 mile up, but gains 2000 feet of vertical by way of 2800 railroad ties. And it's a 4 mile run back down Barr Trail's switchbacks. Time for the endurance training...