Pellius,that`s not HIT bro,that`s a Giant-Set.
I define HIT as having the following attributes: lower frequency (in comparison to traditional routines: 3-4 days max/week), lower duration (not going over an hour), progression (trying to exceed your previous performance and varying the stimulus) and lastly, and most importantly and most neglected, is intensity -- training hard, pushing yourself, stimulating an adaptive response. I just don't understand how one can think they will improve if they are continuously doing things that are relatively easy. When I reach positive failure on a set, defined as not being able to complete another full rep in good form, that's when the set really begins for me. Often times when eeking out the last rep and I will say to myself, "OK, now it begins."
Often one gets caught up in semantics. If you are not doing one set per body part and training each muscle group once every 10-14 days then you are not doing HIT. To me volume training is anything over 9 sets/body part. Jones use to say "Train your muscles anaerobically and train your body aerobically." That why he had Casey jump from one exercise to another with little or no rest. You call it giant sets. When I did shoulders last Saturday, after warming up, I did dumbbell laterals starting with a weight that I got six good reps on, followed by some partials, and worked my way down the rack without stopping until I hit the 15 pounders. You call that giant sets and I call it drop sets. Same thing in my mind. I almost always do partial on my last set. It use to be called burns. The fellas over on IronMan call it X-reps. Whatever.
BTW, I am of the belief that training in this manner, training your muscles anaerobically and your body aerobically, is NOT the idea training protocol for muscle hypertrophy. Boyer Cole commented that moving so fast you didn't give your body enough time to recover so that you can really push the muscles (not the cardiovascular system). He also mentioned, and this may be even more important, is just spend a bit of time psyching up. Focusing and visualizing. Winding up and building momentum. If you got 8 reps the last time you want to get the 9th rep or die trying.
I believe that circuit training, giants set, or whatever; is best for athletic conditioning and the most productive use of your time for general health and fitness. No need to separate strength training and cardiovascular conditioning. For strength and muscle hypertrophy you have to slow down the pace some and really focus on moving weight.