“You are here like in a Metro station, in and out,” said Mihai Brestyan, who with wife Silvia founded Brestyan’s American Gymnastics a dozen years ago and is trying to figure out ways to keep everything under one roof, especially now that they’ve started a boys program.

Ever since star pupil Aly Raisman came back from the Olympics seven weeks ago with a couple of gold medals, Brestyan’s has been jammed with everyone from toddlers to transfers, the numbers doubling to nearly 700. “The problem we have is to find very quick more coaches to keep the standard,” said Brestyan. “Because you expect the gym to grow but not to grow so fast. You need to have good instructors to make sure that everyone is doing their job.”

The Brestyans have 15 tutors now, supervising everything from the Mom and Me program to the elite level, which produced both Raisman and predecessor Alicia Sacramone, who won a team silver medal in the Beijing Olympics in 2008.Sacramone’s comeback from a torn Achilles’ tendon fell short of Olympus last summer. Raisman is with her gilded London teammates on the 40-city Kellogg’s Tour of Gymnastics Champions.

Meanwhile, the new quadrennium is underway, the countdown clock to the 2016 Games in Rio de Janeiro is ticking, and it’s unclear whether Raisman or any of the Fierce Five will stay for a reprise.

“We don’t know how many of the Olympic team will continue,” said national team coordinator Martha Karolyi. “We have to think about the next generation.”

So Brestyan already has made the first of his monthly trips to the national team’s training center/boot camp in Texas, where he is an assistant coach specializing in floor exercise. With a couple of exceptions, the September gathering was for more than two dozen juniors, a handful of whom likely will form the core of the next Olympic team.

Raisman may continue, take a sabbatical of a year or more, or retire and go to college. Talia Chiarelli, the other elite gymnast at Brestyan’s, will join Michigan’s varsity team next year.

“It is a little bit scary for me because I need to start all over again,” said the 59-year-old Brestyan. He reckons that he has three or four gymnasts poised to make the jump to the international level (“I don’t want to give you names”) and another 15 young ones coming up behind them.

When the Brestyans opened their first gym in Ashland in 2000, less than four years after emigrating from Israel, they had only 20 kids in the building. Five years later, Sacramone won a gold medal at the world championships in Melbourne, then made the Olympic team. Raisman followed. Now Brestyan has a pipeline of five-ringed hopefuls.

“You have Alicia first, then you have suddenly Aly,” he said. “Same coach, same system, same gym. Wherever you look, everybody knows who is the coach of the champ.”

Sacramone earned 10 world medals, the most ever by an American gymnast. Raisman won three in London and missed a fourth on a tiebreaker. Every gymnast on the planet saw her jump into Brestyan’s arms after she’d clinched her floor gold. No other recommendation is necessary.

“Mihai really proved himself this year,” said Karolyi, who has known Brestyan for nearly four decades. “He had success with Alicia and really came through with Aly. He has the coaching style that is really able to get results. He has the traditional Romanian philosophy, which is strong physical conditioning and creating the situation in training to be as close as possible to competition.”

Lorena Quinones, who competed for Puerto Rico at the Games, now trains at Brestyan’s gym. So does Venezuela’s Alexandra Avendano. Aya Mahgoub, who won a gold medal for Egypt at last year’s Pan Arab Games, has been here for five years. The German women, who trained at Brestyan’s earlier in the year and went on to have their best Olympic finish in two decades, want to come back. “I don’t care for what flag they are competing,” said Brestyan. “They can come here.”

Chiarelli, who moved from Ontario in 2006 when father Peter became the Bruins general manager, turned up on Ray Avenue by serendipity.

“We had to find a new gym to go to, and the first one that came up when my mom searched on Google was this one,” she said. “It was kind of chance.”