text: Generally a shift refers not just to a player, though, but the whole line, or defensive pair.\n\nPlayers generally come on and off in lines, and your three forwards (left wing, right wing and center) will generally come out together, work a "shift" together and come back off the ice more or less at the same time (unless as usual your left wing's still doggedly chasing their center around the offensive net and won't let him come out for love or money).  \n\n"Double shifting" means you're putting one player out on one more shift per rotation through the bench than he'd usually play.  So say I played with Line 1, and then Line 2 went out and then instead of the regular center on Line 3, the coach put me in again.\n\nIn rec hockey you might do it because you're missing a player (like you have two lines of three and one line of two).\n\nIn pro hockey it means you're desperate to get a certain individual out there because he's producing, but the wisdom of that is debatable except in isolated cases.  Double shifting is extremely tiring.  On the bench, you tend to need every second of rest you get.\n\nDefense works in shifts too.  A defensive pair (whichever combination the coach sends out) on the ice is also doing a "shift," which ends when they both come off.\n\nShifts should be kept short.  The idea is to go out there, give it everything you have until you're cooked and then get off the ice again.