What is a muscle pump?

I keep reading about people getting Muscle pumps after there workout. What are they? and how do they happen? I have read reviews with people saying the product gave them a great pump, but can they occur without the use of supplements?

Well NO2 claims to give you a muscle pump, no matter whether you work out or not. But basically a "Muscle Pump" is when you lift weights and the blood rushes to the muscles, mostly can occur during any strenuous activity, such as your calves during cardio. NO2 also can make your pumps last for hours, but it isn't proven whether that actually gives you any real muscle gain or not. I wanted to try it out,  but I will have to wait a bit for the next paycheck.

Your muscles look and feel bigger than they do when they are not pumped.  They'll be a bit firmer, too.  Personally, I find it the easiest to feel in my biceps and I can see it the best in my pecs.  As far as I can tell, the only benefit is the boost in confidence you get when you look all pumped, but I haven't researched it much.

Yes, Peeves, pumps are possible without supplements.

A "pump" is (as Gun Ryo started to explain) the result of a muscle becoming engorged with blood and waste byproducts. This is a natural consequence of repeatedly and forcefully contracting a muscle. When you flex a muscle repeatedly under a load, like curling a dumbbell for 4 sets of 12 reps, the muscle produces waste products (lactic acid) which must be flushed out of the tissue. Excessive lactic acid buildup happens rapidly, and results in the burning sensation toward the end of a set. It's your body's way of shutting down what you're doing, so you don't injure yourself. Of course, this game is all about pushing that limit, and working beyond what your brain is telling you your muscles are capable of.

The rush of blood to a muscle being worked strenuously serves two main purposes: it flushes out the lactic acid, and delivers nutrients to rebuild and repair.

Typically, a pump is a short-term phenomemon, lasting only an hour or two after a workout. Supplements like Nitrix and NO-Xplode can prolong that condition through vasodilation (vaso = blood vessels, dialation = expansion). By relaxing the blood vessels in your muscles, Nitric Oxide causes you to carry a great deal of that pumped sensation over a longer period.

One last thing: while a good pump is not necessarily an indication that you had a productive workout, the inability to acquire or sustain a pump for the typical 1/2 hour to 1 hour after a workout is usually taken as a symptom of overtraining.

Yes, that's me in my avatar, and NO, I don't look like that today. That was taken back in Jan '07, and I lost most of that progress when I slacked off last year. I'm on my way back, tho, and I'm using that photo for inspiration.

Thanks guys that info was great. veggeep you probaly explained everything i wanted to know... thx