Developed in the 1970s in Europe -- where it's called powerchair football -- power soccer is played using battery-powered wheelchairs on a basketball court. Each team has four players; three play "up" and one serves as goalie. Beyond that, the rules are similar to outdoor soccer, complete with corner kicks, free kicks and yellow and red cards for fouls.

"With only three guys playing up, you really can't afford a red card," which sends a player out of the game, said Pete Winslow.

Running into an opponent on purpose is illegal, but with multiple wheelchairs zipping around in a confined space, crashes, some of them hard enough to knock over a chair, are inevitable.

The front of the chairs are outfitted with a small cage -- 8 to 20 inches high -- that the players use to ram the ball. Many also mount metal plates on the sides of their chairs that they use to deflect passes.

The shots can pack quite a punch. The most powerful is a spin move in which the player races up beside the ball and then spins his chair 360 degrees, whipsawing the corner of the cage into the ball. The shot comes off the cage at speeds upwards of 20 miles per hour.

"I've taken a ball in the face," Winslow said. "It hurts."