The only reason for a stamina idea would be to slow the player, so that other participants have a chance for action. In effect, its a meter to implement a turn based system. So, when implementing something like this, remember that you have to have your meters compliment each other, and not block each other''s effects. Otherwise the player ends up finishing that soda before his next turn comes up.

Speaking of RPG''s, Secret of Mana had a pretty unique way of dealing with this. You could attack as much as you wanted, but your accuracy would go down with each swing. You didn''t spend too much time "resting" either, because it only took a second to recharge. This way the battles could be real-time without degrading into Diablo-style hack''n''slash.