I just gotta get this off my chest - because it makes me crazy. I hear SO many women say they don't want to lift weights or do P90X because they don't want to get too bulky. Honestly, how many fit and in shape women do you know PERSONALLY that you would describe as bulky? Ok, how many have you seen - outside of fitness magazines and competitions?
I personally know 2 women who compete professionally, and they are the closest thing I've seen to "bulky". Ladies, you're not going to pick up a weight and all of the sudden turn into a professional male wrestler. It doesn't work that way. Our bodies were not made to get large like that. There is so much work and effort and supplements that you would have to purposely invest to manipulate your muscles to a point that could be described as "bulky". It's not gonna happen by accident. It's certainly not gonna happen by you picking up a 15lb. dumbbell.
Excuse #2 - I don't really need to build muscle, I just want to lose weight
Guess what? Muscle burns fat. Yup, you heard me. So when you're sitting at your desk at work, doing nothing - your muscles are burning fat. The more muscle you have, the more efficiently that fat is burned. That's why lots of women who are slim also have very toned muscles. Those muscles helped them get slim. And how do you get toned muscles? You need to lift weights. Or - use your own body weight as resistance.
Take it from someone who knows.