ANTWERP, Belgium (AP) -- All of 16 years old and given to giggles, Simone Biles showed she is ready to carry the weight of a nation.
She anchored the strongest U.S. team performance in world championship history on Sunday, and it didn't take long for U.S. women's team coach Martha Karolyi to put this in perspective.
''We are ready to go for Rio,'' Karolyi said.
After a dozen medals and a long week of domination, the Americans are clearly in a position of strength for the 2016 Olympics.
And Biles, a newcomer to the team, is much the reason. First, she won the all-around Friday and then she added the floor event Sunday. She finished with four medals overall.
''All the hard work has paid off,'' she said. ''It is so exciting to be part of that. I cannot ask for anything more.''
The U.S. team ended with 12 medals, exceeding its previous high of nine at the 2005 Melbourne championships. The Americans had almost double those of their nearest challenger, Japan, with seven.
Perhaps most amazing, Biles may actually have surpassed Kohei Uchimura as the most successful gymnast of these championships. If the Japanese great proved to many that he is the greatest gymnast ever by winning a record fourth all-around world title, he came just short against Biles this week.
Both won two golds and four medals overall, but Biles had a silver and a bronze to add compared to the two bronzes for Uchimura, who won his first parallel bars gold Sunday.
Yet, as a nation, no one was a match for the United States, which came to Antwerp without the defending and Olympics women's all-around champions and with a lot of question marks.
Next to Biles, Kyla Ross was almost a strong, getting three silvers over the week and proving she had blossomed from last year's Olympic team gold medalist into a strong individual performer whose grace and elegance is a counterpoint to Biles' power and jumping.
''It is usually the year after the Olympics can be a little bit hard and rocky, but we were able to find again some of the old generation,'' Karolyi said. Beyond Ross, one such gymnast was defending champion McKayla Maroney, who won the vault Saturday.
Karolyi stressed, however, that gold today means little tomorrow. She insisted she has several 13-year-olds already gearing up for Rio, when they will be just old enough to compete.
It will make it all the tougher for 2011 champion Jordyn Wieber and Olympic gold medalist Gabby Douglas, who sat out this year's event, to walk in and reclaim their spot.
''We have some more reserves,'' Karolyi warned .
Well behind the U.S., Japan had seven medals overall, including four gold. But other perennial contenders are clearly rebuilding. China had only two medals overall, even if they were gold. Russia had four, but only gold from Aliya Mustafina on the balance beam. And Romania left with just one bronze.
For the U.S. team, even the men started contributing again. They had only one gold in 2011, the last world championships. In London last year, they brought back a mere bronze.
This time, four different men added two silvers and two bronzes, showing some strength in depth.
''We are doing awesome,'' said John Orozco after finishing third behind joint gold medalists Uchimura and China's Lin Chaopan on the parallel bars. ''I came into these worlds, I was like, 'it is really going to be hard for us medals this year.' I am so proud of the whole team.''
At an individual level though, no one gets close to Uchimura, who at 24 looks fresh, healthy and eager enough to add many more years to his dominance. In Antwerp, he said he wanted to continue until Tokyo hosts the games in 2020.
For all of the stature of Uchimura and the promise of Biles, the performance of the day came from Olympic high bar champion Epke Zonderland. The Dutchman set the Sports Palace alight with a routine full of gravity-defying leaps to win the last event of the championships. He edged Fabian Hambuechen of Germany and making Uchimura settle for bronze.
After winning a record fourth all-around world title early in the week, Uchimura was at his best again in the parallel bars, enough for a shared gold with China's Lin Chaopan.
Uchimura won his first gold in the parallel bars. Usually serene and withdrawn, he was pumping his fists and flashing big smiles to the thousands in the stands after John Orozco of the U.S. took third place.
Aliya Mustafina won Russia's first gold medal of the championships, edging Ross on the balance beam. Mustafina, the 2010 all-around champion, was nearly flawless as she twirled, twisted and jumped at will on the narrow beam, and then watched Ross and Biles fall short of overtaking her. It was Ross' third silver of the championships. Biles took the bronze.
In the men's vault, South Korea's Yang Hak-seon dominated again. The defending and Olympic champion brought a difficult new vault to Antwerp and performed it well enough to slip past American rival Steve Legendre. Kristian Thomas of Britain was the bronze medalist.