The Edmonton Oilers revolutionized penalty killing two years ago by turning a shorthanded situation into a positive factor. Until that season, most NHL teams fell back into a conservative defensive box to combat opponents with a manpower advantage.

However, the Oilers, using such offensive stars as Wayne Gretzky and Jari Kurri in penalty-killing circumstances, collected 36 shorthanded goals, 11 more than any other team in NHL history.

Last season the New York Islanders saw the advantages of such a maneuver, both on the scoreboard and psychologically, and often put Mike Bossy out with Bryan Trottier to keep opposing point men on the defensive.

This year the Washington Capitals join the trend. Bob Carpenter and Mike Gartner, two 50-goal scorers, will see considerable duty as part of a penalty-killing unit.

If a power play goal is meaningful, a shorthanded goal can be devastating. Such a score, or even success in killing a major penalty without yielding a score, can give a team a mental lift and turn a game around.

There is another advantage to being able to kill penalties: A team that does not need to worry about paying a price for fouls can intimidate opponents with impunity. The Philadelphia Flyers' Stanley Cup triumphs in 1974 and 1975 were built on such tactics. Sometimes it seemed the Flyers were a man short for half the game, but they were masters at deflating power play pressure.

Penalty-killing forwards work harder than anyone else in a hockey game, rarely skating longer than 45 seconds unless they are under pressure beyond that time.

The forwards first try to prevent opponents from moving out of the other end, then they alternately sweep at the puck carrier, trying to break up the play or force the power play unit to dump the puck rather than carry it over the blueline.

Once play has reached the defensive zone, the forwards concentrate on the point men, keeping them as far out as possible and trying either to block shots or anticipate passes. It is then the job of the defensemen to block shots, clear rebounds and, if possible, steer opponents away from the slot area without being tied up and distracting the goalie.

The goaltender has more to occupy him than merely stopping shots headed his way. He must handle pucks dumped behind the nets and he must try to deflect passes through the crease.

Sometimes pure luck seems to play a vital role in the success or failure of penalty killing. Two years ago, the Capitals ranked No. 1 in the NHL, with their 86.7 percent ratio of success the league's best in seven years. But last season the team fell to 14th at 76.2 percent and nobody could explain the collapse.

The inexplicable failure of the penalty killers last season and continued problems in training camp was a factor in the decision to use Carpenter and Gartner.