Ji Xue Wei can't remember when she was hand-picked to join the training team of the China National State Circus. Now aged 10, she is already a veteran. This "normal" school day for Ji Xue Wei will involve being tossed like a ball between the hands, feet and heads of two older students.
"Acrobatics is a form of art, demanding hard work. The longer and harder the training is, the more skilful and more superb the acrobatic gymnastics will be," says Zhang Yu-sheung, the team leader in charge of the 50 Chinese and 20 Russian children training at the Beijing Municipal Acrobatic School.
Six is the optimum age to start training as an acrobat: bodies are still supple enough to be stretched and bent into the most unnatural of contortions, and the children are old enough to stand the gruelling training regime of more than 12 hours of physical exercise a day.
Chinese circus acrobats are now regarded as the best in the world, and this is the best school in China: the source of talent for the China State Circus and China Acrobatic Troupe. Children are the little stars of the troupe's nightly shows in Beijing and its tours around the world. "Russia is regarded as number one in animal training, but China is best in acrobatics," says Mr Zhang.
In the main gym, the girls juggle and twiddle plates on sticks. They somersault and practise pyramid balancing acts. Boys hurl themselves like monkeys between two 20ft poles, performing daring somersaults as they go. Beginners are caught in their falls by safety harnesses. A contortionist holds her position for 10 minutes.
For Western children it may look like a fun way to receive an education. But this is not play-time and there is no laughter as the students concentrate grimly on developing their skills.
These children are taught to be tough. The day starts early. At six in the morning they brave Beijing's frost for their morning run, followed by 90 minutes of more cardiovascular exercise.
After 45 minutes for breakfast they spend the rest of the morning working in the gym, going through exercise regimes to achieve maximum flexibility of their legs and waists, and working on their basic skills of somersaulting and handstands. Their training also includes physical exercise, dance, martial arts and acting.
After a half-hour lunch break the afternoon is devoted to practising circus acts. The students follow up to four courses from a total of 50, including trick-cycling, stilt-walking, tight-rope acts, knife-throwing, plate-spinning and pole stunts.
By 5pm they will have completed almost 10 hours of training, but that's not the end of their day. Those ready for public performance will charm and amaze tourists in a 90-minute evening show in a city centre theatre. The rest undergo a further three hours of training. They can finally rest at 10pm.
"The training is now tougher and more scientific," says Mr Zhang. "We have many very experienced teachers who know how to train students in a scientific way and within a short period of time. In the past it took two to three months to teach an acrobatic skill, now it takes just one."
Accidents occur, but not often. "We have equipment to protect them, such as a safety rope. But once they are skilful in doing these acrobatic acts they won't get injured. Starting so young is part of the reason they become so fearless," says Mr Zhang.
Academic studies are not a priority in this circus school. Pupils spend only Wednesdays and Saturdays in the classroom, learning Chinese, English, maths, art, music and morals. What little free time they have may be spent playing ping-pong or cards, or singing karaoke songs. Mr Zhang is proud that this regime quickly sets his pupils apart from other children. "They develop an extraordinary willpower, learn to be hard-working and bear hardships. They are more strong and independent than other children."
But there is a price. Like her classmates, Ji Xue Wei spends just 10 days a year with her parents. "We don't feel homesick anymore," she says, her face devoid of emotion.
Three or four students a year will not be able to stand the pace and drop out. Those who survive can look forward to jobs for life in the state circus.
Formed more than 40 years ago, the circus draws on China's traditional folk culture. Unlike more academic institutions it survived unscathed during the Cultural Revolution, though for a spell it had to perform acts with a sound political message. "One programme celebrated a good harvest. Another was called 'training of Red Guards', showing the range of basic skills," says Mr Zhang.
The circus has prospered with China's rapid economic development and growing tourism industry. The purpose-built school campus was officially opened in January, ready to double its intake of students from home and abroad.
The modern classrooms, gyms and dormitory blocks stand alone among frozen fields beyond the urban sprawl, not far from the Beijing Development Zone industrial park. A giant Coca-Cola bottling plant is the school's nearest neighbour.
The 20 Russian pupils were chosen last year from more than 3,000 applicants. Around 10 students a year are recruited from north-east China. "Children there have good physical quality and more easily accept the tough work. Besides, they are used to the weather in Beijing, which most people from the south cannot get accustomed to," says Mr Zhang.
Strength, good health and resilience are the qualities needed for young acrobats. Most pupils come from families with a little cash to spare. Parents must pay around pound;44 a month, the equivalent of a fortnight's salary for a teacher in China. It is the only Chinese circus school to enrol foreigners. They are charged US$800 a month (pound;495), including board, lodging and tuition, and come mainly from former Soviet countries with strong circus traditions.
The 20 Russian students are from the north-eastern Russian autonomous republic of Yakut. Harmia, seven, comes from a Yakut circus family. Her mother is a dressmaker, her father an artist. Affectionately holding the hand of her teacher, Zhang Ningning, she says she longs to be an acrobat. She wants to go home for a holiday too, but that may not be possible this year because of the economic woes of her home country.
But few of the Chinese boys and girls seem to be here through choice. They pay a heavy price in their quest for stardom. Though Mr Zhang says they are driven by love of their art, their sad, empty faces tell a rather different story.
Indeed, most seem to be there to fulfil not their own dreams but those of their parents - that their children should not only have a better life than them, but a glamorous one under the spotlights, and a chance to travel the world.
"My mother decided to send me here. I don't know why," says Sun Zheng-zheng, 10, from the northern city of Harbin. She sees her family so rarely that she has no idea what work her parents do. Zhao Wei-zheng, 13, was recruited from a Beijing school. "Touring was fun, but this is not my dream. It is tiring," he says. He hopes his father will find him a job outside the circus once he has graduated.
Ren Yuan, 11, comes from Anshan in Liaoning province, where her father is a steel worker and her mother a hawker. She is a dutiful daughter. "The head of the circus visited our school and chose me," she says. It is an offer that no Chinese worker can refuse. "Now if I work hard enough I will get many chances to go abroad." Even so, her first tour to Russia was gruelling and she found that while on the road the long hours of training gave little time for sightseeing or rest.
Wang Di, 10, daughter of another steel worker from Anshan, is more enthusiastic. "I really wanted to come here and become an acrobat. Life here is better than home. The training and food are good. Of course I miss my parents - I'm looking forward to going home for the Chinese New Year Holiday."
As for the dangerous acts she performs, she says: "I am not scared of anything anymore."
Those who stay the course will work as acrobats until they are too old or injured to carry on. Some will still perform in their thirties, forties and even fifties. Once their performing days are over they may work as trainers, administrators, dress-makers, set designers and artists.
But that is far in the future for these children, who labour day after day for an entertainment industry. Those of us who lament the fact that Britain rarely produces world-class athletes would do well to realise that this can be the price of such excellence. Whether that price is worth paying is debatable.