Head north on I-45 and watch the Houston skyline disappear in the rearview mirror. About 90 minutes and half a dozen turns later, you're hanging on as your vehicle bounces along a rocky dirt road to a ranch-gymnastics factory in the middle of Sam Houston National Forest. It is here, at Karolyi's World of Gymnastics, that the most elfin and resolute U.S. Olympians are strained, stretched and selected for service.

Every month 20 to 25 girls leave their home gyms -- reigning world all-around champion Shawn Johnson travels south from West Des Moines, Iowa; other members of last year's gold-medal-winning world championship team come in from Indianapolis, Orlando and other gyms in Texas -- for four-to-five-day testing camps, supervised by national team coordinator Martha Karolyi. Her husband, Bela, molder of Olympic champions such as Nadia Comaneci and Mary Lou Retton, built the gym and ranch in 1984, three years after he and Martha defected from Romania. In part through the force of Bela's personality, the gym has become the centerpiece of what is one of the strongest women's gymnastics programs in the world.

"For quite some time the most advanced gymnastics countries were taking a centralized approach to training," says Bela. "We were not, and it showed." After USA Gymnastics designated his gym as the national team's official training center in 2001, Karolyi started running an especially rigorous series of drills to increase strength, flexibility and stamina. Among them: 10 consecutive handstand presses, a handstand hold for 60 seconds, a timed rope climb with outstretched legs and pointed toes and 20 leg lifts from a hanging position, touching toes to fingertips. He also staged mock competitions that mimicked world and Olympic events in every detail, down to the gymnasts' march into the room and the acknowledgment of the judges.

Though gymnasts improved, many personal coaches squawked about the camps, in part because of Bela's domineering style. In 2001 Bela ceded the reins to Martha, who began running the camps using her husband's prototype while also reaching out to the personal coaches for ideas. (Bela still insists that the magnet on the Karolyis' refrigerator that reads EVERYBODY IS ENTITLED TO MY OPINION actually belongs to Martha.)

Coaches have since warmed to the camps, which are both demanding and inspiring. A walk of fame at the ranch shows the names of U.S. gymnastics Olympians and world team members. Because gymnasts live at the ranch during the camps, the gatherings build camaraderie. There are lighter moments: "We'll be working out, and suddenly a horse will be looking in the window," says Samantha Peszek, a 2007 world team member. Stroll around the 2,000-acre ranch, which has turkeys, antelopes, emus and other creatures, and you might find Bela talking in his fractured English to an 18 months pregnant camel, "When you going to give up the baby, Elvira? We waiting on you."

There will be little joking around come summer. Though Olympic trials will be held in Philadelphia in June, Martha will have a say in the final team selections after a camp at the ranch starting on July 16. No spectators will be allowed, and the gymnasts will be seeking the approval of only one judge. "It's one kind of pressure to perform your best routines in front of 10,000 people," says the 16-year-old Johnson, "but it's a different pressure when you have to perform them in front of Martha."

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