Do what you want and see where it takes you. Remember, if it doesn't work don't lose heart and change your workout. You should change it it now and then anyway as it only takes your body around 10 days to resist and work out your schedule/routine. This might mean simple things like changing reps and sets. Or on cardio machines, if you do intervals on a bike/cross trainer/rowing machine, 20 second flat out and 10 seconds slow. Change the intervals. In some cases it could be a whole revamp change.
I think HappyBlue knows more about the weight training side then I do. I'm more into fitness these days myself. HIT/interval type cardio.