One of the elements of ice hockey that can be most confusing to beginning fans is line changes. Unlike other sports, ice hockey does not require a timeout or a specific point in the game for players to move on and off the ice. Because hockey is so intensely physical, players are only on the ice for short “shifts” of a minute to a minute and a half. Two full minutes is a long time for a player to be on the ice, and if you hear announcers talk about a “long shift” or about players needing a line change, it’s usually because they’ve passed the 60- to 90-second mark.
Players have to choose their change opportunities carefully. If they change in the middle of an ongoing play, they could endanger the team’s ability to score. If they don’t time the change properly, they can also end up with too many men on the ice, which leads to a two-minute penalty, creating additional problems for the team.
As a result, line changes usually occur after a play is complete and the momentum of the game has shifted. As the players head for the opposite end of the ice, one or two players might head for the bench to be replaced by other players who are usually sitting on the edge of the boards by the players’ bench, ready to jump over and into the action.
The player on the bench can’t move onto the ice until the player who is leaving the game is within five feet of the bench. If the new player mis-times his entry, there will technically be six men on the ice for a second or two, and the referee will whistle a penalty.
When the game is stopped, either by the goalie (the only player allowed to stop the puck), icing or any other situation that leads to a face-off, the team sometimes will switch out all five players.
Line changes are much easier to follow in a live game than during television coverage, during which attention is focused more on the on-ice action. Announcers will mention player changes, and the broadcast usually features a display of player numbers to show who is currently on ice and who is switching places with whom. However, if you can get to a live game, this is the best place to watch this intriguing ballet that makes ice hockey different from other sports.
SOURCES: Hockey Rules in Pictures, an Official Publication of the National Hockey League