Updated

For years, the Chinese men's training sessions were can't-miss performances, gymnastics and coaches from pretty much every other country cramming into the stands to gawk at the world's best team.

Those days are over. And China's stranglehold on Olympic gold might be, too.

The reigning Olympic and five-time world champions practically had The O2 Arena to themselves Wednesday, not a single coach from perennial runner-up Japan or the United States bothering to stop by. Oh, sure there were claims of scheduling conflicts, talk of trying to focus on themselves. But it's obvious the Chinese have lost some of their luster.

"They're going do what they're going to do. We're going to do what we're going to do," U.S. assistant coach Tom Meadows said. "Watching them work out isn't going to change what we're going to do."

No, but it sure wouldn't have happened four years ago.

The Chinese have run roughshod over the rest of the world for the last decade, so dominant they often had the competition won simply by getting off the bus. They've won five straight world titles — often by huge margins — and could have opened their own jewelry store just with their haul from the Beijing Olympics. They won all but one of the seven men's golds there, and it might have been a clean sweep if they'd bothered to have anyone try and challenge for the vault title.

But a switch to smaller teams has left the Chinese vulnerable, and a less-than-inspiring performance at last year's world championships have teams like the Japanese and Americans believing they have a real shot at the top of the podium. The men's competition begins Saturday.

"The team event, to have the gold is the main goal," three-time world champion Kohei Uchimura said.

China's formula for success was to take an all-arounder like defending Olympic champion Yang Wei and surround him with specialists, gymnasts who are spectacular on an event or two. When teams had six members, there was more than enough talent to cobble a powerhouse together.

But Yang retired after Beijing and, with teams reduced to five gymnasts for the London Olympics, China is struggling to adapt. That was evident at Wednesday's training, when they had only three gymnasts to put up on floor exercise, vault and still rings. Only three scores count in both prelims and team finals, but it's taking a big risk not having someone who can step in as a last-minute fill-in.

Sure enough, the Chinese were forced to scramble when Teng Haibin, the 2004 Olympic champion on pommel horse, was forced to drop out of the games with a torn muscle in his left forearm. Teng, who apparently was injured at a pre-games training camp, tried to gut through the injury, training with his arm wrapped in a heavy bandage. But it was clear he was in agony, and he botched pretty much every routine he did.

The Chinese had barely left the building when they announced that Teng was withdrawing and would be replaced by Guo Weiyang.

It's not just the numbers game, though. The Chinese used to strut into an arena as if they owned the place, laughing off sloppy practice sessions. Now they seem lackluster and insecure.

When Zou Kai, he of the gold medals on floor and high bar in Beijing, landed one tumbling pass on his knees, he got up with a look of concern etched across his face. Despite the empty arena, the Chinese could barely be heard encouraging or cheering for each other.

"Nobody is on top of things today," U.S. captain Jon Horton said. "Everybody was all over the place."

True.

Even Uchimura, who has been otherworldly since finishing behind Yang in Beijing, was a mess, peeling off high bar twice, botching the landing of a tumbling pass on floor and spilling off pommel horse. All of the Americans struggled on vault, and Horton fell on the same high bar release move three times. After the third fall, he stood and glared at the high bar for what seemed like several minutes.

"I should have just walked away because I've been on fire with that release lately, and I think I let it get into my head," Horton said. "I hate to say it, but it's kind of shaken my confidence a little bit. But I'm going to get back in the gym tomorrow, do a few more, and make sure I catch them and build it back up."

The Chinese have to hope another two days of practice is enough to fix their woes, too. French gymnast Yann Cucherat says he has no doubt they will.

"It's always the same with them," he said. "At podium training, they make not very good gymnastics. But at the competition, it's like a machine."

But even machines can break down.