Feeling pumped...

[mikeysauce]

You know when you are working out and you get muscle pumps and your muscles explode inside the gym...what causes muscles to be pumped even when you are not working out...For example when I do back my back gets huge...when I leave the gym it feels fatigued and small...after a protein shake a shower and some rest I go out at night or for the next couple days and it feels like back is huge and pumped again..What causes your muscles to do this?

[Luminaire]

I like to compare the effect to a boner, BLOOD RUSH, you start working a certain part of your body and theres a blood rush, which is why you might also notice a major increase in vascularity.

[*Narkissos*]

after a protein shake a shower and some rest I go out at night or for the next couple days and it feels like back is huge and pumped again..What causes your muscles to do this?

Glycogen supercompensation.

Post-training your muscles are able to (quite willingly) 'suck up' (and store) 3 times their normal capacity of glycogen.

[EcToMoRpHiAn]

I like to compare the effect to a boner, BLOOD RUSH, you start working a certain part of your body and theres a blood rush, which is why you might also notice a major increase in vascularity.

lol, great comparison. It is true though.