Anybody doing P90X or Insanity

Ruger2506

Like the title says. Anybody doing these? Good, bad, insights, etc? While I do have dumbbells at home (where I currently work out) I like the looks of Insanity as they don't use weights and just use gravity and body weight.

I understand strength training and have a background in it. However I've always struggled with incorporating my core into the program. It looks like these programs do a good job of that.