NFL culture calls for a player to bounce back after a big blow; Bush sat out one play after the Brown hit. Bob Rosato/SI

"He was lucky," Brown says. "His elbow was pinned against his body, protecting his rib cage, or else I probably would have broken his rib. What did it feel like? That collision, I didn't feel nothing, because he was pretty much defenseless. It was like running through a cardboard box. Seriously. Cardboard box."

THE CULTURE OF THE HIT

Everything in football begins with the big hit and flows from there, like blood pumping from a beating heart, feeding limbs and organs. Someday business schools will teach courses on the runaway success of the NFL in the latter part of the 20th century and into the 21st. They will explain how the modern professional game was shrewdly built from humble roots into a 365-day-a-year machine through groundbreaking television contracts, relentless marketing, clever scheduling that promotes parity, Lord only knows how much money wagered on Sunday afternoons (not to mention on Thursday-, Saturday- and Monday-night games) and the cross-cultural phenomenon of the Super Bowl. They will probably ignore the visceral truth at the center of the issue: "It's people thinking they're watching a bunch of barbarians beating on each other," says Jeremy Shockey, the New York Giants tight end. It is bloodlust, built into the fabric of a sport.

And big hits are big business. They not only fuel the core audience but also spawn cottage industries such as ESPN's Monday-night "Jacked Up" segment highlighting the weekend's five biggest legal, noninjury hits, and EA Sports's fabulously popular Madden NFL video games, in which crushing hits are enabled by movements on the controllers. Big hits thrive in an outsized, cartoon world, where every play offers a chance to see Wile E. Coyote smashed by a falling boulder. The entertainment value is off the charts. Blowups are swiftly posted on YouTube (and just as swiftly yanked when the NFL's copyright police intervene). "People want to see violence," says Brown, "and every collision in the NFL is violent." Football without concussive hits is Ultimate Frisbee.

Yet there is a yawning disconnect at work. Television and video do little justice to the epic force at work when two NFL bodies collide. "Fans? They don't have a clue," says All-Pro linebacker Ray Lewis, who over his 11-year career has probably initiated more seismic collisions than any other active player in the league. He is sitting on his corner stool in the Baltimore Ravens' practice-facility locker room, bent at the waist, talking in a stage whisper, tapping a visitor's knee for emphasis. "Most people sit back and look at it and think, They're animals," he says. "They look at us like we're animals for entertainment.

"They sit at home and watch and go, Ooooo, owwww, woooo. But then do they ask themselves, I wonder, does his head hurt now? How many hours did he sleep comfortably last night? Good hitters have been hitting for a long time. You can feel knots all over my head, and there's a place where my hair doesn't grow anymore. I've been hitting people so long, you just pray that nothing happens like with that boy in Cincinnati." (Linebacker David Pollack, the Bengals' first-round draft pick in 2005, fractured his neck making a tackle in the second game of last season; he is rehabbing and hopes to return to football.) "You pray for that not to happen," says Lewis. "To anybody."