[Heads up: Ferruggia's always blunt and occasionally crude, so don't click through if that bothers you.]
I've never made "bulking" my focus in my training, but I though this three-part piece by Jason Ferruggia on "Cardio While Bulking" (part one, two, and three) had quite a bit of useful advice and insight into integrating cardio and intervals into your workouts without injury or overtraining.
Here's one thing that really grabbed me:
If you choose sprinting as your form of interval training you could get hurt; it's an ugly truth that has to be faced. The thing that will lead to even more injuries is following faulty interval protocol advice. Normally it is recommended to do 30-60 second intervals when they are being performed on a stationary bike. A lot of people take these recommendations and apply them to sprinting. This is a huge mistake! Nobody can sprint for 30-60 seconds. Ok, not nobody; but most average people can't do it. World class athletes can sprint for that long, but not everyone else.
He then elaborates, so click through for more (that bit in particular is in part three). Anyway, the reason it grabbed me is because I've always just blindly applied the Tabata protocol to sprinting, without considering that the original studies were done on bikes. Of course, the "as hard as you can" part of my interpretation allows me to "sprint" for 20 seconds at a slower pace then I'd run the 40, for example, but it still kills me.
