RIO DE JANEIRO – When she took on the task of rebuilding the U.S. women's gymnastics program, Martha Karolyi felt certain of one thing. "We didn't want to copy anybody," she said. "Because a copy is never as good as the original."

Over the course of 16 years, Karolyi, 73, molded an approach to training gymnasts that was fresh, innovative and utterly American. As she oversees her final Olympic competition, USA Gymnastics knows how hard it will be to find a replacement as good as the original. Under Karolyi, the U.S. women have won 87 Olympic and world championship medals — a haul that dwarfs that of any other country — and are set to add more at the Rio Games, starting with Tuesday's team final.

Simone Biles and her U.S. teammates plan to send their matriarch into retirement in grand style. The five-member team, which could be the most gifted group in U.S. history, is an overwhelming favorite to win team gold. And no one in the world compares to Biles, who could leave Rio with five golds.

The Texas ranch built by Karolyi's husband, Bela, will remain the home of the women's national program. Gymnasts from all over the country will continue to meet there once a month to train in the Karolyis' semi-centralized system. Though it won't be the same without Martha, they said, their goal is to keep it as close as possible.

"The USA is incredibly strong, and that's because of the system," said Rhonda Faehn, a Coon Rapids native who is vice president of the U.S. women's program. "It isn't going to be taken for granted.

"Everything Martha and Bela brought to the table has been absolutely incredible. It will never be forgotten."

The Karolyis fled Romania in 1981 and came to the U.S., bringing their brilliant brand of gymnastics with them. They came up with the idea of a semi-centralized system in the late 1990s, when the Americans were at a low point. In the system, athletes stay at home and train with their regular coaches, then gather once a month at the Karolyi Ranch outside Houston for camps led by Martha.

Her exacting, regimented approach has created an assembly line of superstars, with a new crop of youngsters always ready to step up. The system has led to greater team unity, as gymnasts spend a long weekend together every month. And dozens of coaches have learned from Karolyi, too: They come to the camps with their athletes, then take new knowledge home to share.

Though Karolyi politely deflects questions about her legacy, she is deeply proud of what she created.

"The most important thing was [deciding] what direction we wanted to go as a country," she said. "We thought we could be very good if we trained hard, united our effort and had a common goal.

"I feel like we have a system now that really works for this country. It has proved itself."

Biles, who has not lost an all-around competition in three years, is expected to run away with the Olympic all-around gold Thursday. If she succeeds, she would be the fourth consecutive American to win the Olympic all-around title, following Carly Patterson, Nastia Liukin and Gabby Douglas. Before that run, the U.S. had only one Olympic gold medalist in the all-around, Mary Lou Retton in 1984.

Liukin said it will be hard to imagine the program without Karolyi. "I had such an amazing experience with Martha," she said. "It's almost sad to see it come to an end, because my whole gym career was under her hands and under her eyes. It's going to be very strange and different. But I know she's also ready to enjoy life a little bit, and not have that stress and pressure."

Faehn said USA Gymnastics hasn't solidified the details of the succession plan. That will happen after the Rio Games. She said the group does not plan to make any changes to the system, and it will search for a leader who can manage it as well as the Karolyis have.

The Karolyis won't be far from the next generation of U.S. gymnasts. They play to continue living at the ranch, in the home Bela built.

Bela retired several years ago and now putters around the property, caring for the camels, ostriches and other exotic animals he keeps. Martha, who is more of a city person, hasn't disclosed her retirement plans. She still has one thing to check off her to-do list before stepping aside.

"She wants to go out with a bang, and she will," Retton said. "The system is in place, and it's time for a new regime. Change is always hard. But USA Gymnastics is going to be just fine."