For the uninitiated, it's easy to dismiss NASCAR as a bunch of good ol' boys (and the occasional girl) driving cars plastered with ads around in a circle, wasting fuel and turning left for hours at a time.

Take a closer look and you'll see the sport requires incredible precision for marathon stretches of time. NASCAR isn't about peak performance. It's about identifying bottlenecks and weaknesses, eliminating mistakes to shave tenths of a second off a lap time. Minor mistakes can ruin entire races, whether on the first lap or 400 laps in. Nowhere is all of this more evident than during a pit stop.

Drivers come off the oval and into pit lane anywhere from four to a dozen times, depending upon the length of the race and how things play out on the track. Races run hundreds of miles, requiring frequent stops to replace tires and refill the 18-gallon fuel tank. Crews can tweak suspension setups and frequently repair broken or bent bits.

To be competitive these days means getting a car fixed up and on its way again in 12 seconds or less.

In a race where cars can clock two miles in a minute, every second in the pits is crucial. Getting in and out quickly can mean the difference between 1st and 5th. Or 15th.

In Formula One, more than a dozen mechanics can change four tires in two seconds. NASCAR teams can send just six mechanics "over the wall" into the pit box. Speed and economy of motion is essential, as is staying out of everyone's way. This is harder than it sounds. To be competitive these days, that means getting a car fixed up and on its way again in 12 seconds or less.

It's a brutal ballet, with fireproof suits instead of leotards and flying lug nuts instead of grande jetés.

Let's Break It Down

Here's how a pit stop goes:

It all starts when the car comes off the oval and down pit road. Crew members stand by with tires, air guns, and fuel. When the car is just yards away, everyone jumps over the short concrete wall that separates the lane from the crew area, and moves into position. .5 seconds.

The right tires, those on the far side of the pit box, are serviced first. The jack man—who uses a hydraulic floor jack—raises the right side of the car. The fuel man, wearing a smock to keep gas off his Nomex firesuit, sticks an 81-pound, 12-gallon fuel can into the fuel filler on the rear left corner of the car. 2 seconds.

Once the car's lifted, the two tire men use pneumatic air guns to remove each wheel's five lug nuts, then remove the wheels simultaneously. 5 seconds.

After tire man has removed the lug nuts and pulled the wheel off, his tire carrier slaps the new wheel in place, returns the old one to the wall, and grabs a fresh one for the left side of the car. 7 seconds.

Once the tires are installed on the right, the jack man drops the car, runs to the opposite side and lifts the car even as the two tire changers are removing the lig nuts. They pull the tires and the tire carriers do their thing. At that point, it's down to the gas guy. Once he's filled the tank—he wiggles the gas can to tell everyone the job is done—the jack man drops the car, the driver drops the clutch, and the race goes on. 12 seconds—if no one screws up.

If necessary, a seventh crewman can jump over the wall specifically for safety-related purposes, like removing a tear-off plastic sheet from the windshield (to ensure good visibility) or handing the driver a bottle of water. He cannot touch the car in any other way.

Controlled Chaos

"It's controlled chaos," says Joe Piette, pit crew coordinator for Stewart-Haas racing. "Most of the time controlled, but all of the time chaos."

When the car stops in the pit stall, five lug nuts are removed from each tire and they go flying. "They're all over pit road," says Piette. "Guys get hit with them, cars will spin their tires over them and shoot them out the back of the car."

A single mistake during a pit stop can put a team as much as a lap or two behind, if not more. During last weekend's FedEx 400 in Dover, Delaware, driver Carl Edwards drove off with a wrench still stuck in his car, dragging a crew member valiantly trying to remove the tool. In addition to the time it took to remove the wrench, Edwards was forced to take an excruciating drive-through penalty down pit road at just 35 mph. He finished 19th.

The guy that puts on the tire, we would like him to do that in 0.7 seconds. If you do it too often in 0.8 seconds, you're too slow and your job could be in jeopardy. Andy Papathanassiou

On top of all that, pit crew members must follow strict rules that dictate things exactly when they can hop the wall and how far they can let a tire roll away before it's a problem. Cameras film every stop, and eight officials use video analytics to scrutinize every stop to make sure everything was kosher. Screw-ups are penalized, and backed up with video evidence presented to the team.

Consistency is key. The pit crew must do its job the same way every time. The crew succeeds, and fails, as one—five guys can do the fastest stop of their lives, but if the sixth guy is half a beat behind, it doesn't mean a thing.

"The guy that puts on the tire, we would like him to do that in 0.7 seconds," says Andy Papathanassiou. "We have superstars who can do it in 0.6 but if you do it too often in 0.8 seconds, you're too slow and your job could be in jeopardy."

A New Kind of Science

Papathanassiou (a Greek from New Jersey, they call him Andy Papa in the South), a former Stanford football player, joined Hendrick Motorsports 23 years ago. He brought an athlete's mentality to a job long considered an incidental part of being a mechanic—something done quickly, but with little thought. He was among the first to argue that a pit crew should be a specialized unit that trained like athletes. He implemented a recruiting program modeled after pro sports. "We bring [college athletes] here and bring them into the NASCAR world," he says. "Nobody plays pit crew when they're eight years old, but we have those people that ... have a natural affinity."

Stewart-Haas Racing/Getty Images

Papathanassiou seeks out athletes at the end of their collegiate careers, folks like wrestlers and lacrosse players for whom there is no pro league, or football and baseball players who aren't draft material.

And once they're on the team, they train constantly. Hendrick Motorsports has all the trappings of a college athletic program, including certified coaches and trainers, a 5,000-square-foot gym, an outdoor training facility with field turf, running track, and special forces-inspired sand pit and bar obstacle courses for cognitive and team-building training.

Having strength is key. Even if a pit stop is over in a matter of seconds, it's grueling work: For safety reasons, crew members wear full Nomex racing suits (and soon, Nomex underwear!), hoods, and helmets—making every movement more challenging. But it's about more than muscle. Balance and agility are equally important—fall while changing a tire, stumble while slinging that jack, and you can say goodbye to that 12-second time. "On Mondays we do a yoga session for everyone," says Piette. "Most of the guys really enjoy it. A good stretch on a Monday morning is a good thing."

"We have a ten-month season," Papathanassiou says. "So we don't have a long off-season to just do nothing and get healthy. All those injuries and rehab, strength and conditioning, has to be dealt with in-season." As a result, the crew focuses on flexibility and injury prevention as much as strength and agility.

If All Goes Well ...

Watch a NASCAR race, and the timing of a pit stop can seem almost random. One lap a guy is running in third place, but then he has a bad stop and is down in 18th. But if you keep watching, race after race, you'll see the same teams filter up to the top again and again. That's the importance of consistency. Yes, each pit stop is a mad sprint, but each is also part of a marathon race, in a marathon season: the premiere Sprint Cup series include 36 races over 10 months.

Hendrick Motorsports driver Jimmie Johnson, who won at Dover last week, didn't qualify particularly well and wasn't a factor for most of the race. But toward the end, he picked his spots and landed at the right place at the right time—and not by accident. It was Johnson's tenth win at Dover, and 74th victory overall.

He's just the fifth driver to post 10 or more wins at a single track, joining NASCAR royalty like Richard Petty, Darrell Waltrip and Dale Earnhardt Sr—names even non-fans might recognize.

Driving talent and strategy is the biggest part of that, of course. But in today's NASCAR, you don't make it to the top—and you certainly don't stay there—without a crew that can fix you up and get you back on the oval in about the time it took you to read this sentence.