This is where every girl who wants to be an elite American gymnast must come, at some point in her career, to pay tithings in the form of blood, sweat and often tears, to coach Martha Karolyi

Carolyn Drake for TIME Martha Karolyi in the old gym

The girls aren’t around, but their presence lingers everywhere: their images hang in larger-than-life posters that cover the walls — Olympic and world champions, frozen in fierce, midcompetition poses; their chalky white footprints cover the mats that litter the gym floor, tracing the crazy circuits of routine after routine performed at the USA Gymnastics National Team Training Center. The resin that anchors tiny gymnasts precariously to their equipment cakes their calloused hands too and is shed in ghostly prints on the 10-cm balance beam, on the uneven bars that loom 2.4 m off the ground and even on the restroom door. That might be the dusty legacy of where the reigning Olympic all-around champion jumped onto the beam; those could be the footprints of the country’s best gymnast on the uneven bars; that might be where the world vault champion stuck a difficult landing.

It’s a rare quiet day at the gym, a respite in between the busy days when anywhere from 20 to 30 members of the national team are tumbling, vaulting, balancing or swinging through their routines. This is where every girl who wants to be an elite gymnast must come, at some point in her career, to pay tithings in the form of blood, sweat and often tears, to coach Martha Karolyi. This is where every gymnast with Olympic dreams earns the right to represent the U.S. and wear the coveted team leotard. This is where Karolyi puts the girls to the test, once a month, for four strenuous days. It’s called training camp, and while there are bunk beds, shared cabins and bucolic surroundings deep in the woods of New Waverly, Texas — complete with lakes, boats, tennis courts and a pool — it’s nothing like the carefree summer excursions that most of us know.

“I make it very clear for the girls. They come here for one single reason, that’s to train,” says Karolyi in her sharp, Hungarian-inflected English.

(PHOTOS: See TIME’s Exclusive Images from Inside Camp Karolyi)

The remoteness of the location is actually an advantage, at least in Karolyi’s eyes. A 30-to-40-minute drive from Houston, reached after a nearly 10-minute ride along a dirt road that winds through a forest where deer and wild boars roam, the training center is the focal point of the 1,200-hectare ranch that Karolyi and her husband, gymnastics icon Bela, share. For the girls, making the pilgrimage has but one purpose — to impress Karolyi. While a selection committee that includes Karolyi, a USA Gymnastics representative and an athlete representative determines the Olympic team, everyone — coaches and gymnasts alike — knows that the person with the strongest voice is Karolyi. “She is the big lady,” says Shawn Johnson, the Olympic all-around silver medalist in Beijing. And the way to Karolyi’s heart? Nothing short of perfection. “We strive for perfection. I state that every moment when I have a chance,” Karolyi says. “If that is not your goal, then you are in the wrong place.”

It’s a hard goal to attain, perfection — some may even say by definition, impossible — but the drive to achieve it has made Karolyi, and the U.S. women’s gymnastics team, among the most successful in the world. It’s also drawn criticism for the strict and, according to at least one former student, abusive methods it’s pushed the Karolyis to employ. But for Martha, it’s an absolutely realistic goal — because she saw it happen, in 1976, when she coached a young Romanian girl named Nadia Comaneci. At the Olympic Games in Montreal, Comaneci, only 14, scored not one, but seven perfect scores on her way to winning the all-around competition. Since becoming the U.S. national team coordinator in 2001, Karolyi has collected an impressive case of trophies, leading the American “girls,” as she calls them, to 59 world or Olympic medals, including unprecedented back-to-back all-around championships in 2004 and 2008. That’s the prestige event of the sport, in which a single gymnast is recognized for outperforming her competitors in all four gymnastics events — vault, balance beam, uneven bars and floor exercise. There are no perfect scores in gymnastics anymore, but that doesn’t stop Karolyi from searching for it, seeking it out among the dozens of gymnasts that fly from around the country to log hours of tumbling and twirling at the National Team Training Center.

Karolyi, however, faced an even greater challenge this year. For the first time since becoming national team coordinator in 2001, she and her system were put to a different test. For the past three Olympic Games, U.S. gymnasts and coaches have agreed to an unorthodox selection process that includes not just the Olympic Trials, but an additional “trial,” conducted at the Karolyi ranch, several weeks prior to the Games, during which Karolyi and the selection committee put the girls through a mock meet before making their final decisions about the Olympic squad. “It was almost like anything you did before the camp selection didn’t really matter,” says Carly Patterson, the 2004 all-around Olympic champion. “Once again, you had to prove yourself all over. That was definitely very scary.” But because of the short time between Olympic Trials and the start of the Games in London, Karolyi was forced to name the five-person team at the Olympic Trials. “I always like to wait longer, but I feel [the Trials] created an atmosphere very close to what we will get at the Olympic Games, so maybe it was a good factor to show who handled the stress,” she says.

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Naming the squad this way makes Karolyi nervous heading into London since gymnasts training so hard are prone to injuries and rejiggering such a small team, carefully selected to give the U.S. the greatest chance of winning the team gold, can have devastating effects on the girls’ performance. And despite the fact that under her leadership, the U.S. team now rivals world powers in the sport, including Russia, Romania and China, no U.S. women’s squad has won the team gold since 1996. That’s the medal that Karolyi wants. Going into London, the U.S. women are the world champions. Four of the five girls on that team are heading to the Games, including the reigning all-around world champion Jordyn Wieber. For Karolyi, the ultimate vindication of her vision would be a team gold medal and a three-peat in the all-around event. If that happens, the achievement would be as much a personal victory for Karolyi as it is a professional one — a validation of the decision she made years ago to defect from Romania to the U.S. and build a brand-new gymnastics powerhouse.