cardio after burning out your muscles doing anaerobic excercise like weightlifting can really be effective in burning calories and increasing your cardio abilities like stamina and endurance
think about it, you get good results when you do something when you are fresh, you get more results from doing the same thing when you are already tired
I prefer to do HIIT but I do long intervals, 5 minutes to be exact. I don't have alot of room, so I run in place, do jumping jacks, rope, squats and thrusts, and toe raises, and some rounds I'll do just 1 excercise the whole time or I will do a round of sprawls, fake shots, striking (heavy bag usually or focus master) or ground and pound with some positioning work. Usually 5-7 sets of 5 minutes with 1 minute of rest. You haven't lived until you've rolled around on the ground in pain from a non stop 5 minute calf raise set. Then you realize you are only halfway there and you have another 5 minute calf raise set to go.
Do upperbody until your gassed and then do 7 rounds of that type of training full out and you will sweat pools of sweat and gain mad rips, I guarantee. Doing that type of training has given my calfs about 50% more definition in about 2 years and I had really ripped calves to start with.
