A well hydrated or volumized muscle cell is a happy one. Seems to favor protein synthesis. We know from animal models that stretching a muscle also causes hypertrophy.
Glycogen storage in the muscle pulls water in (1 g glycogen = 2.8 g water). Thus, a muscle that is filled with glycogen is going to appear fuller and harder. Moreover, if the concept of a volumized cell = happy cell, then it may well enhance protein synthesis.
The muscle pump during exercise is a little different. When you complete a few hard sets two things happen. One, you force fluid out of the vascular compartment into the interstitial space between the muscle cells (muscle pump). Two, metabolites such as La, K+, etc accumulate as a result of muscle contraction causing an osmotic gradient that favors fluid movement out of the vascular compartment into the muscle. Thus, the pump. I think the reason those on a low carb diet don't experience the same pump may have to do with less metabolite accumulation (less substrate available) and that the muscle itself is glycogen/fluid depleted and even with the fluid shift, doesn't become as engorged.
If most of you checked your Hct before working legs, then about 10 sets into legs when they are really pumped, you'd find your Hct increased considerably.
W6
Please Scroll Down to See Forums Below 
.jpg "Research Chemical Sciences")
.png "Research Chemical Sciences")
). I'd say at the very least, growth is not dependent on the pump.
