I have a question its been really bugging the hell out of me, when ever I work out I’ll do a certain weight, and I’ll be maxing my self out, I’ll do a full set and the on my second set I’ll do around 4, after which I have to move down, but once I move down a weight I can only do a couple reps and then I’ll have to move down again and so on and so on, I was wondering how I can bring up my endurance, so that I don’t plummet down after moving down a weight. Any help would be great....