getting a pump is helpful but not the only way to get it done. I lift heavy, my rep ranges are all over, but i also try to get a pump with at least one exercise. Fillin your muscle so full of blood with a combination of stretching will assist with growth, but again, its just another tool in the arsenal.
Like most things, it has its place.
"Abs on a skinny guy are like big boobs on a fat chick - they don't count." -Shelby Starnes