If anyone believes that a larger muscle group needs many more set's ( 20+ as opposed to 4-9 set's max), than they would be mistaken. And if anyone believes that a muscle group must be hit by many different exercises and angles than they to would be mistaken. I don't care what the winner of the 2005 title of Mr. Big Ball's say's in all the mag's or his $39.95 video's as to how he does secret workouts using 20 or 30 SS's per body part every workout, that is not the real world of weight training.
Check out some of the PL'ers and Olympic lifter's for unbelieveable extra thick, muscular backs, traps, shoulders, leg's, etc. Some BB'ers would give their right nut to have that muscle mass but they take the path of thinking that more (sets) is always better. And while your at it, check out some of the really huge BB'ers who toss around massive amounts of weight every workout. Most all those workouts are short and to the point and not the marathon 20+ set's that can cause more damage than good. If a trainee can not completly work a muscle group close to it's max, for future potentional growth, between 4 to 9 set's than his whole approach to training is misguided. Good Luck.
Side Bar: Sorry... but I don't answer personal post.