A good pump can be a positive by-product of a exercise, but there is no guarantee that increased muscle size will follow. Positive in that it can make you feel you have accomplished something when the muscles become gorged with blood and temporarily larger. But that can fall in the class of a false positive. Standing in front of a mirror and giving the front double bicep pose after endless sets of arm work is, like the mirror it's self, just an illusion.
It is a natural progress to bring the nourishment's in the blood to the working area. When the blood fills a muscle area to capacity, with a good pump, than there is no more room for any more blood to enter the area. Any more sets, to increase a pump to the muscles, is just a waste of training time.
iIf you can get a very good pump with 3-4 sets max (which you should), there is no reason to do 10 to 15 more sets for that muscle area. It is like putting a empty glass under a faucet and running water. You will only get so much water into that glass, the rest will spill over and be wasted.
I am not against the pump, just that it is a part of the whole when the goal is to build muscle size and even strength. It's place of importance should be put into perspective when training. The goal for most anyone is not just to go for the pump it's self in a workout. Good Luck.
Side Bar: Some of my more productive workouts have been with GVT for a 6 to 8 week training cycle. A very good pump is produced, though no the main reason for this type of cycle. Timing of a light pump through out a given training day can also produce muscle size increases for some. Something like the all day, once an hour light, pumping session for some. Seems to work well with arms, delt's and calf's.
