if you are having trouble getting a muscle pump when you are working out the culprit may be too little carbs. Carbs bind to water and without them the ability to and maintain a muscular pump is diminished. While a pump is not necessarily required for growth it usually follows that the muscles that pump up the easiest grow the fastest. Some muscle scientists have experimented with cuffs to restrict blood flow and localize it in the muscle being worked. They have found a significant benefit in building muscle size doing so. But the practice can be dangerous. To achieve similar results do static holds in between reps for example 5-hold-5-hold.