Today I did the P90X3 CVX workout. All I used was one 3-lb weight and 15 minutes in I was sweating like crazy. It reminds me of the time Sarah said a big muscle dude came into her toning class. It was his first time and she recommended he use a light weight. Of course, being a big strong guy with something to prove to others in the class, he ignored her advice and went with the heaviest weights she had in the studio, not realizing what they were going to be doing with them.
She said by the end he was struggling and just looked a mess. He was able to deadlift a house but had probably never mixed weights and cardio before.
Same thing here with this CVX program. You don't have to use a lot of weight to get a helluva workout (on the DVD, Tony Horton says not to use anything more than 15 lbs). I was only abot to go 20 minutes instead of the full 30, but I felt good about what I did and any time I'm drenched in that much sweat, I know I got in a good workout.