Many people want to get in shape without having to spend the money and the time it takes to go to a gym 3-4 times a week. With drive time back and forth to the gym, a 1 hour workout can easily turn into a 2 hour event. This is why many people are choosing to exercise at home with popular workout programs like P90x, Insanity, Turbo Fire, Brazil Butt Lift, 10 Minute Trainer, or many others.
I'm sure you've seen the Insanity infomercial, and you have seen the trainer that leads the Insanity workouts, Shaun T, he is a pretty muscular dude. But a common question out there is, will Insanity build muscle? I've personally done Insanity and to be honest, after the 60 days, I was probably in the best shape I've ever been in. I had lost some weight, my cardio levels had improved, and I was looking as ripped as I ever had. But to answer the question, I've got to say no, Insanity does not really build muscle. But that is not necessarily a bad thing.
The Insanity workout is not a muscle building workout per se, but rather a fat burning workout which will also turn fat into muscle. The Insanity workout includes a lot of pushing up type exercises, and a lot of squat type exercises, but with no weights. With Insanity you are mixing up cardio and resistance training at the same time, which is a huge calorie and fat burner. So you will be getting leaner, and stronger, and your muscles will tone up, and that that is how you will get that "ripped" look.
Insanity is a great workout, but if you are looking to bulk up and gain muscle mass, this might not be the workout for you. You will be better off going with P90x or the new arriving Body Beast workout. Which workout you choose to do really just depends on what your goals are.
Unfortunately Insanity really will not build muscle. But it will turn fat into muscle so if you are a heavier set person, it may be perfect for you. However, if you are a skinny guy looking to gain size, you will be better off going with P90x. P90x has much more resistance workouts where you are able to use heavy weights and focus solely on getting bigger and stronger. Both P90x and Insanity are both great workouts, which one you choose will depend on what your fitness goals are.