Football is heavily and undeniably drenched in testosterone, but testosterone run through a clockwork mechanism. The sport's allure derives from its combination of mind-blowing, oversized athleticism and intricate, almost anal strategy. These contradictory qualities make pro football weirdly irresistible. It's like watching a virtuoso violin-playing giant on a tightrope who gets an electric shock every time he plays a wrong note.

It isn't that football players can do any one thing better than other athletes. They don't possess the awe-inspiring combination of precision and strength of gymnasts. They can't run as fast as track stars. They don't have the stamina of wrestlers or soccer players, the hand-eye coordination of baseball players, the killer instinct of boxers or the catlike grace of basketball players. But no other sport requires its players to possess as many of these qualities as football does. Speed and power, the primal capacity for violence and strategy, explosiveness and endurance, skill and guts -- football players must have them all.

And, just to make it more American and over the top, they must also be either fast beyond belief or very, very large. Lately, a group of bionic characters have appeared who are both -- 250-pound guys who run like the wind, have no body fat and can jump four feet vertically from a standing position. These Terminators lend the game an even more monstrous fascination. To stand on the field and watch genetic freaks like Lawrence Taylor or Charles Haley in action is actually frightening: There is no precedent in the human experience for men so enormous who move with such incredible speed.

Without the right showcase, however, even great athleticism is not enough. What sets off those skills, as a spare setting displays a gem, is the way they are confined to tiny, discrete segments of time. Each play in football is a violent mini-theater in which a complete drama of precision, savagery and grace is enacted in just four or five seconds. At the snap of the ball, a hyper-specialized, ill-humored menagerie -- cheetahs, elephants, hyenas and lions -- is released from its cage. Huge, disconcertingly agile tackles drop back, nimbly keeping their enormous centers of gravity in front of onrushing defensive ends who are 6'6", run 40 yards in 4.6 seconds and can snap off small trees with their forearms. Fleet wide receivers with magnet hands explode downfield, their feints fencer-fast, shadowed like a bad conscience by little defensive backs so gifted with speed, reflexes and quickness they could play any sport they wanted -- tennis, basketball, track, anything. Psycho-eyed linebackers, 260 pounds of angry muscle tuned to a point just short of snapping, crash into 300-pound guards who can run 30 feet faster than you want to think, while fending off 240-pound fullbacks who will lose their $400,000 gig and have to go back to sweeping the parts room unless they regularly inflict skeletal damage on their foes. And in the middle of it all stands the quarterback, with his magic idiot switch that blanks out everything, the cacophony and swirling movement and the threat of imminent physical extinction, except one fast-moving two-foot by two-foot square 40 yards away, to which he must deliver the ball in one second or have it picked off.

There is no other human activity, outside of a symphony orchestra, in which so many complex and related physical tasks are performed together in so short a period of time.

This compressed, controlled chaos makes football the team game par excellence. But it also does something more. When one learns how to read it, it changes one's perception of time. That fraction of a second when the linebacker turns his head the wrong way, that moment when the running back shifts his weight from one foot to another, become endowed with a grand fatality that is only heightened by the endless slow-motion replays.

In some obscure but undeniable way, all sports offer miniaturized and clear-cut imitations of reality, little universes in which someone actually wins and actually loses. That's why they're pleasurable: It's the same mimetic impulse that lies behind art. If soccer, with its chaotic, never-duplicated ebb and flow, its longueurs and rare climaxes, is a simulacrum of thought in all its randomness, football is an imitation of the human will, guided by strategy, girded by repetition, aiming at smaller, incremental, attainable goals on the way to a larger one. Football is often and justly compared to war: It can also, less obviously, be compared to science. In no other sport do plays, rehearsed sequences of exact movement, occupy such a central role. Former 49er coach Bill Walsh's famous "script," in which the first 15 offensive plays were pre-ordained, is reminiscent of a scientific experiment: Instead of reacting to the variables, the raw and chaotic reality represented by the defense, he factored that chaos into his prediction of the outcome.

It's the tension between the cognitive precision, the meticulous chess-game rationality, of the plan and the glorious, unpredictable physicality of the players' execution, that gives football its unique appeal. All athletic performance is unpredictable, but football's violence makes it doubly so. The great defensive back Ronnie Lott, asked to describe what it felt like to be hit by him, said to understand it you would have to have a friend hit you as hard as he could in the back with a Louisville Slugger. "Selling out," Lott called the attitude required to hurl one's body in the path of onrushing behemoths. (This from a man who, when he broke his little finger, simply had the tip amputated so that he wouldn't miss a game.) The mental state required to sell out, to sacrifice one's body play after play, is a precarious one, which is why mere skill offers much less of a guarantee of victory in football than in baseball or basketball. Without a slightly maniacal edge, even the best teams will lose to ordinary ones. In baseball, good pitching beats good hitting; in basketball, the better team almost always wins. But in football, you've got to consult phases of the moon: There's a werewolf factor. As former Atlanta Falcons defensive lineman Tim Green points out in his excellent, no-nonsense look at the realities of the NFL, "The Dark Side of the Game," "the NFL player has simply learned how to tap into the dark side of the human psyche." Those teams that fail to tap deeply enough usually lose.

In the end, though, the joys of football come down, like those of all sports, to athletes performing extraordinary feats. That those feats involve the two primal ways of achieving physical mastery, speed and strength, may explain the game's atavistic draw. It is no accident that the first game children play is tag, or that running and wrestling were at the heart of the ancient Olympics.

I discovered the true athletic majesty of the game a few years ago. I was at the San Francisco 49ers' training camp, watching defensive backs drilling against wide receivers. No linemen were involved. Joe Montana was the quarterback, Jerry Rice the receiver. The players were in shorts and light pads. The defensive back, Darryl Pollard, lined up about four yards off the line of scrimmage from Rice. I was standing just behind Montana. A ringside seat at Mt. Olympus.

At the snap of the ball, Rice took off upfield. On television, I had always noticed his odd running style, at once fluid, powerful and almost mechanically repetitive, with his upper body kept very straight. Standing a few yards away as he accelerated like a drag racer at the backpedaling Pollard, I realized, with a sympathetic shudder for the defensive back, not only that Rice was much faster than he appeared to be on TV, but worse, that his almost exaggeratedly efficient stride was absolutely unreadable: No shift in body weight, no slight tilt, betrayed either a fake or a move. It was like watching a very fast robot. After 20 yards, the robot's feet executed a double fake, rightleft. The two stutter steps took about a tenth of a second. Incredibly, Pollard didn't bite on the left move, but he was forced to react to it, turning his hips just slightly to his right. At exactly that instant, Montana released the ball and Rice pushed off his left foot and cut upfield to the right on a post pattern, not breaking stride, his body still as straight-up and robotic as ever. He suddenly appeared under Montana's pass -- which had been thrown before the cut to an empty space on the field -- snatching the ball out of the air with his big hands just as Pollard, who had spun back from his right and closed ground with extraordinary rapidity, jumped high into the air, missing the ball by inches. Rice jogged back to the line of scrimmage, expressionless.

I was awestruck by Rice, of course, but I almost expected to be: He's the greatest receiver of all time. What was revelatory, in those three and a half seconds, was Pollard. The guy was a solid player, but hardly a household name. He was one of the troops. He had just performed an astonishing athletic feat -- and failed. That's when I realized just what kind of athletes these guys were.