Players live for it, fans love it, media celebrate it -- and all bemoan its devastating consequences. The brutal collision of bodies is football's lifeblood, and the NFL's biggest concern

	When Brown met Bush at full speed early in the Eagles-Saints playoff game, the shock waves reverberated far and wide. Kevin C.Cox/WireImage.com

BIG HIT 1
Jan. 13, New Orleans

Reggie Bush had never been drilled like this in his life. In high school and college he had always been the best athlete on the field, too fast and too elusive to leave himself open to a clean shot. But here, in an NFC divisional playoff game against the Philadelphia Eagles, his initiation came suddenly. A swing pass floated into the right flat, a flash of green helmet and white jersey, and now Bush was on his hands and knees on the turf of the Louisiana Superdome, crawling in his black New Orleans Saints uniform like a small child, sent back to his infancy after getting blown up by Eagles cornerback Sheldon Brown. The play resonated throughout the league: Watching it on TV a thousand miles away in Chicago, Bears linebacker Brian Urlacher rose in appreciation. "Those are the ones you dream about," he'd say later. The New Orleans crowd, frenzied only seconds before, fell silent.

One day earlier Saints coach Sean Payton had given quarterback Drew Brees the game plan. The first 20 plays were scripted, the second being 52 Z Shark F Wheel. The snap count was "second sound," indicating that Brees would step up under center, shout "set-hut," and the play would begin. "I saw that hit on Reggie coming the night we got the game plan," says Brees. "Anytime you go on second sound, you're trying to keep the defense off-balance, but the risk is, you're not getting a great look at the defense. And the Eagles have a pretty nice little blitz package."

The Saints lined up with three wide receivers and Bush as the single back behind Brees. Brown set up as the outside corner, across from wideout Terrance Copper and five yards off the line of scrimmage to Brees's right. The quarterback's first read on the play was outside linebacker Dhani Jones, who was on the same side of the field as Brown and Copper. If Jones blitzed, he'd be unblocked and Brees would go to his hot read: Bush on a flare route to the right. Copper was running straight down the field, theoretically taking Brown with him. Theoretically.

"We had been working on that play all week," says Brown. "We even watched film the morning of the game. The first time we played them, they killed us with the flare route. They want to run me off and get Reggie matched up one-on-one with a linebacker. So we put in a play where, if the receiver releases, I just sit and then fly up and hit Reggie on the flare." (The Eagles' safety would pick up Copper.)

Jones blitzed, untouched. Brees lofted the ball over Jones's head toward Bush. But Brown didn't backpedal. He read the pass and drove toward Bush, running 11 yards at full speed. Bush reached for the ball and held it for .14 of a second -- a time gleaned from a frame-by-frame study at NFL Films -- before Brown launched himself into the air, driving his right shoulder into Bush's chest and stomach, arms extended. The impact lifted Bush into the air and carried him backward three yards, the two players' bodies floating together until Bush's back slammed into the artificial turf as the ball bounced away.

Bush rose quickly to his hands and knees, then to one knee and then to a standing position. And then back down to all fours, pawing at the ground. "I popped right up," says Bush, smiling at the memory. "Then I was like, Ooooo, I can't breathe, my wind is gone. I better get back down. I never felt anything like that before." Bush sat out one play before returning to the game.