LONDON -- Kayla Williams probably ruins the curve in her classes at school, too.
The 16-year-old American, who was still competing at the level below elite five months ago, looked like an old pro Saturday in winning the vault title at the world gymnastics championships. Only when she stood atop the podium did she seem overwhelmed, taking several deep breaths as she waited for the gold medal to be put around her neck and fighting back tears as the national anthem played.
Just how big a leap was this? Think LeBron James going straight from high school to the NBA -- if James had won the NBA title his rookie year.
"This past five months, or however long it's been, has been the most hectic and crazy," Williams said, wide-eyed. "But I've learned a lot and I finished it off as best I could."
China, meanwhile, finished things off in its usual fashion, winning three of the five titles Saturday. He Kexin added a world title to her Olympic gold on uneven bars, Zhang Hongtao won pommel horse and Yan Mingyong closed the day with a win on still rings.
Romania's Marian Dragulescu won his fourth world floor title -- not bad for a guy who retired after the Beijing Olympics.
"I was feeling like I can still win medals," said Dragulescu, who retired because of chronic back and neck pain. "I'm glad, because today I won."
Williams' rise just doesn't happen in gymnastics. Newcomers do make a splash at a world championships or Olympics all the time, but odds are they've had some international seasoning at the junior level at least.
Not Williams. She was at the Level 10 championships in May, so far off the radar that her only trip to the Karolyi ranch before the world team was selected was for a developmental camp.
"My teammates and the rest of the USA delegation have been very good about telling me to treat it like just another meet," Williams said. "If I was by myself, I'd definitely be a nervous wreck."
Neither Olympic silver medalist Oksana Chusovitina nor bronze medalist Cheng Fei was at the worlds, but this was hardly a slouch field. Williams beat the Olympic champion, Hong Un-jong, who fell on both her vaults, as well as Europe's vault champion, Ariella Kaeslin of Switzerland.
Williams' power is her obvious strength. While some gymnasts look as if they're trying to muscle every flip or using every bit of strength to not step out of their landing, Williams makes it look easy. She looks as if she's exerting all the effort of a cartwheel. It showed in her score, a 15.087 that was more than a half-point ahead of Kaeslin.
This was the first world vault title by a U.S. woman, giving the Americans four medals in the first three events. Bridget Sloan and Rebecca Bross went 1-2 in the all-around Friday night, and Bross tied for bronze on uneven bars Saturday.
"That's a huge accomplishment," Sloan said. "She should be very, very proud of herself."
China was so dominant at the Beijing Games its national anthem was played more often than some of the songs on the arena play list. It won both team titles, all but one of the men's events and He took the gold on uneven bars.
But like most countries, China is in transition the year after an Olympics. Several top names have retired and, with no team competition, the Chinese sent some youngsters to see if they might fit in the plans for the London Games.
"It's a new cycle," Yan said. "We're just trying to find our way."
Yan showed he's more than an able replacement for Chen Yibing, the Olympic gold medalist and two-time world champ on still rings who, in the week's biggest shock, failed to qualify for the final. Rings should definitely count as one of the feats of strength, with gymnasts twisting and twirling themselves while being suspended 8 feet off the ground.
At one point, Yan hung motionless for several seconds, a move so taxing it would cause a dislocated shoulder in most people. Instead of screaming in pain, he drew himself slowly into a ball as if pulled by an invisible wire.
He took a big hop forward on his dismount, but his score was still good enough (15.675) to keep him ahead of the ageless Jordan Jovtchev, who won his eighth world medal on rings.
He was at the center of the underage dispute in Beijing, when questions arose about whether she and others on China's gold-medal team were old enough to compete in Beijing. Gymnasts must be 16 in the Olympic year. International gymnastics officials cleared the girls after reviewing documents, and now He is in the spotlight solely for her skills.
She looked like a hummingbird as she flitted from bar to bar. Her difficulty score Saturday was 7.1 -- almost a point higher than the next-hardest routine. The routine is so tough that unless she falls no one can touch her. She didn't, and no one could.
"I felt very relaxed here," He said through an interpreter. "I have no pressure because there's no team events."
Zhang's routine on pommel horse wasn't as hard as that of Hungary's Kriztian Berki, the reigning world silver medalist. But he did it with such flair and precision, everyone knew the gold was his. Everyone but Zhang, that is.
"After I finished my event, I celebrated myself because I performed very well. Almost perfect," he said. "But I didn't realize I had won the title."