They are like a wave as they crash back and forth following the flight of the basketball, which is being passed from one set of hands to another around the perimeter.

There seems to be no easy way to penetrate this wave. When someone does manage to stick a toe in, the results are mixed.

The Grove City High girls basketball team has mastered the 2-3 zone defense lately, limiting their opponents' offensive opportunities with a clamp-down defense that has turned flow into frustration.

"It's kind of good for our team," said Grove City coach Roger Flynn. "The personnel we have really fits well into it."

Grove City is blessed with two quick guards in Ashley McKnight and Julie Molloy who can come out quickly on a 3-point threat and squeeze in to deny penetration.

The Eagles also have a tall and athletic front court in Alissa Chutz, Sheila Odgen and Jenna Kelly, who, with an average height of 5-feet-9, are adept at clogging the lane and getting rebounds.

"Our guards have really made it work," Flynn said. "They have good overall quickness."

It has turned usually potent, slashing offensive attacks into mere passing clinics while looking for a crack - any crack - to exploit.

There have been few.

Since switching to a predominately zone defense as the calendar turned from 2004 to 2005, the results have been startling.

In the last six games, the Eagles are surrendering only 33.2 points per contest. Points against them are even more difficult to come by in the first half of games, as the Eagles have surrendered an average of just 13.3 points in the first 16 minutes.

"We've managed to keep the scored down," Flynn said. "We've had some good success with it. It has certainly kept us in some games."

Grove City is 4-2 in those games, 10-5 overall, and is in the thick of the playoff race.

The zone also has given the Eagles some breathing room.With a thin bench, Flynn subs infrequently. Playing a zone keeps the wear and tear on his starters down to a minimum."Some of us have been injured," McKnight said. "Playing the 2-3 zone is easier on us. We can stay in the game longer. We don't have a lot of substitutions."But the zone isn't a mode of cruise control. There is still a lot of movement as teams search for weak spots."(The coaches) try to tell us it's not an easy way out," Chutz said. "Some of us are not the fastest in the world to play man-to-man, so it has worked out in that way, too."Assistant coach Mike Hostetler has been the driving force behind the zone. He's the one who runs the team through the intricacies of playing the defense in practice."He has really worked hard to drill the girls in it, so they know their movements and know who they are responsible for," Flynn said. "He's really the person who has made it work."Grove City first used the 2-3 zone as a major part of its game plan against the drive-happy Oil City offense. It worked so well that the Eagles stayed with it.It's not an easy defense to play. It requires a lot more discipline than the basic man-to-man defense, but McKnight said practice makes perfect."We practiced it a lot," McKnight said. "Everyone has a specific job to do, and we know what to do. It just seems to be working for us."It has had to work. Recently, Grove City's offense has struggled to put points on the board. That makes holding the opponent's output down even more important.The Eagles held Franklin to just 23 points in an overtime loss, allowed only 29 to Wilmington and limited Slippery Rock, which is averaging more than 53 points per game, to 37.Only one team, Titusville, has cracked the 40-point mark in the last six games against Grove City."Once we employed it in a game and it was working, I think we developed some pride in it," Flynn said. "And most importantly, the girls believe they can do it."The true measure of whether it is working or not can be seen on the faces of the opponent."You can see them get frustrated," Chutz said. "Franklin was running people through the middle trying to attack it. Other teams try to overload one side, but we always seem to adjust to it."