US Olympians train at least 6 hours per day minimum.
They are usually thin because competative gymnasts train very hard. Most high level gymnast train from 16-24 hours a week. This of coarse keeps them in good shape. There are also plenty of full figured gymnasts in the world as well, but their intense training is the main reason you see so many thin gymnasts.
i did 20 a week
at least 16 hours a day
The usually train between 15 hours a week and 20 hours a week, just running. They spend a lot of other time on conditioning and other training.
As harsh as it seems, they train about 16 hours a day. Being a sports star in China basically translates into who's body can take the most abuse and not fall apart. This is also why their bodies are pretty much trashed by age 20
how many gymnasts are in the world?
Olympic Rowers train 4 to 5 hours per day, six days a week. that time includes only time spent at heart rate above 145. Stretching and rests take 1hour. So its 5-6 hours per day all together.
This answer depends on the competitive level of the athelete at hand. Anywhere between 10-30 hrs for competitive swimmers
it takes around 9 hours (overnight train)