One presumption in team sports is that defenses have the edge at the outset of competition because they merely react to offensive forays that must be developed over time.

And with just one week for star football players from around the state to prepare, the annual Maine Shrine Lobster Bowl Classic generally has lived up to that presumption during its first 17 editions.

The teams have combined to score an average of 31.9 points per game, with the winners scoring more than 24 points just three times while the losers have scored eight points or fewer eight times.

Defenses have posted five shutouts – all by the West – but recently the play has been more balanced, with both teams scoring in double figures each of the last three years.

That has coincided with more balance in the rivalry. The West leads the series 14-3, but the teams are 2-2 in the last four games after the East’s 22-21 win last summer.

When the teams square off at 7:30 p.m. Friday from Waterhouse Field in Biddeford in this clash of the best high school seniors from the Class of 2007, expect traditional game plans to prevail – though execution will determine whether the game is a point-fest or low scoring.

West head coach Matt Perkins understands that. He’s the head coach at Windham High School, which made its Class A debut in Eastern Maine but subsequently moved to the West.

“Being an East guy for so long, it always seemed like a power game in the East, and then I came to the West and it seemed a little more dynamic with more schemes,” he said. “It’s different styles of coaching, but I really had a great experience in the East, there are some phenomenal coaches up there.”

This year’s East squad is likely to employ a power attack, while the West is expected to use a spread offense.

The East features Fitzpatrick Trophy winner Jared Turcotte, a running back from Lewiston who rushed for 1,813 yards last fall, 4,562 yards for his career. He’ll be complemented by the likes of Winslow tailback Justin Lindie (2,200 all-purpose yards last year), Gene Kim of Stearns of Millinocket, Kyle Ross of Hampden Academy and Travis Lee of Belfast.

They’ll work behind quarterbacks Gabe Hinds of Cony of Augusta and Lucas Thomas of Messalonskee of Oakland, who will work behind a line that includes tackles Robert Seccareccia of Bangor and Steve Shea of Nokomis of Newport and guard Andrew Leiser of Mount Desert Island.

“Their offensive line is very big, they move well,” said Perkins. “Their O-line is probably what they’re going to hang their hat on, and they obviously have a couple good running backs there, too.”

The West will be guided by Portland quarterback Chris Treister, who passed for 1,846 yards and 18 touchdowns from the spread offense last fall while rushing for 574 yards and eight TDs.

Brian Sandora of Deering of Portland (1.925 rushing yards in 2006) paces the running attack, while Ben Delcourt of Bonny Eagle is a top receiver. Tackles Andy Nash of Gorham and Chris LeRoy key the offensive line.

Top defenders for the East will include lineman Brad White of Bangor, end Kevin McCabe of Winslow, linebackers David Wallace of Lawrence of Fairfield and Devon Brown of Gardiner and defensive back Aaron Champagne of Lawrence.

Top West defenders include linebacker Stanley Watts of Bonny Eagle, end Raibonne Charles of Windham and defensive back Andrew Pochebit of Cheverus of Portland.

“There are great athletes on both teams, it’s just going to be a showcase of the very best players in the state,” said East coach Mike Marston of Skowhegan. “I think both teams are going to match up well, I think it will be a great football game. I hope it’s a one-point game.”

MAINE SHRINE LOBSTER BOWL

When: Friday, July 27, 7:30 p.m.

Where: Waterhouse Field, Biddeford

Who: Eighty-eight of the best senior high school players, representing all high school football programs in the state, encompassing Classes A, B, and C.

Why: To benefit Shrine Hospitals of Maine.

Tickets: $10 for reserved tickets; $7 for general admission; can be purchased at the gate, at Kora Temple, or from any Shriner.

Lobster Bowl history

(West leads series 14-3)

1990 – West 24, East 12

1991 – West 40, East 0

1992 – West 18, East 7

1993 – West 35, East 12

1994 – West 31, East 18

1995 – West 21, East 14

1996 – West 10, East 0

1997 – West 17, East 16

1998 – West 24, East 0

1999 – East 18, West 7

2000 – West 6, East 0

2001 – West 16, East 14

2002 – West 13, East 0

2003 – East 55, West 8

2004 – West 15, East 14

2005 – West 23, East 12

2006 – East 22, West 21