the only thing i haven't done is the extensions because they're worthless and a waste of time, i do squat/leg press supersets all the time.
Worthless? Waste of time? Well, that is one way to see it, but like all things, everybody have their own point of view. I like to do supersets of presses and extensions, but I do it only every third leg workout. I use 85% from one rep max for both exercises and I do just two sets. I warm up and stretch my leg muscles before these sets, and I do those sets right to the twilight zone. I start with presses, which I do so many that I can, usually 8 to 12 reps, then I change to extension machine and do them to failure. One minute rest and all over again. I never ever get similar pump to my thighs like I have after these two sets. Usually we choose two slightly different exercises for super set, but that what you do is like supersetting squat and squat, and it is difficult to see any point in that. Still, you know what works well with your body, so who am I to tell you to do it differently? Nobody, and that's why I just recommend people that you may try it, and if you don't like it, don't stick to it. I feel sick every time somebody tell me that he do some exercises "all the time", because it usually means just that. Still, if you want to improve your body, you should avoid to do same exercises "all the time" because your body get used to do them, and that doesn't do any good for you. Instead of that, you should keep your body confused via changing exercises time to time, it is only way to keep it growing "all the time". If you combine two basic exercises for superset, the great idea behind that is combine one heavy and on slightly lighter exercise, because this way you can accomplish total exhaustion without overdoing it for any muscle. If you combine two heavy exercises, it is too easy to accomplish overexhaustion and instead growth, you go right in to katabolic state. It is really quite simple if you think about it...
