DERBY DAYS WOMEN'S ARTISTIC GYMNASTICS China v USANational Indoor Stadium, Beijing Sunday - Women's qualification (Subdivision 1, 2, 3 and 4). Wednesday (August 13th) - Women's team final.

FOR A few weeks every four years millions of television viewers around the world become experts on several sports that, otherwise, maintain a presence under their radar.

Gymnastics, for example.

Ever since the Sparrow from Minsk, Olga Korbut, captivated Munich and the world in the 1972 Olympics and the 14-year-old Nadia Comaneci became the 10-point star of Montreal 1976, the sport of saltos and dismounts has become one of the most eagerly anticipated events at each Olympic Games.

While many of the most high-profile events in Beijing will involve individual battles, especially in the pool and in track and field, when it comes to contests between countries, the 19,000-capacity Beijing National Indoor Stadium may be the host to the biggest of them all.

Artistic gymnastics was invented in Germany, developed in Sweden, Italy and Switzerland, and then perfected in Romania and the former Soviet Union. But the latest battleground in women's artistic gymnastics is being disputed by a novel pairing - China and the USA.

Rhythmic gymnastics - the sport of ropes, hoops and ribbons - joined the Olympic club in 1984 and the trampoline was added in 2000, but it is still artistic gymnastics that holds the biggest lure for the occasional spectator.

In artistic gymnastics, the men contest six disciplines - floor, pommel horse, rings, vault, parallel bars and horizontal bar - and women contest four - vault (where the gymnast runs to a springboard and sometimes ends up on blooper TV programmes), uneven bars (two bars five feet and eight feet from the floor), balance beam (in which the gymnast has 90 seconds to mount, jump, turn and flip on a wooden beam) and floor (which consists of a choreographed routine on a square mat 40 feet wide).

Eastern Europeans dominated the four exercises in the past, but this year's tournament in Beijing has been billed as a straightforward tussle between the two new superpowers.

If the American women were not already under incredible pressure, the "Magnificent Seven" - the USA team that won gold in Atlanta 1996 - have been piling on more.

"We have high expectations ourselves of gold and we want nothing less," Kerri Strug said this week. "The Chinese are strong technically, but mentally the US own the competition."

Strug would know a little about mental strength. In the 1996 Games, with the USA needing a high score in the final vault to hold off a strong challenge by Russia, the Arizona girl fell on her first attempt, injuring an ankle.

She limped to the end of the runway for her second attempt, and landed perfectly on one foot - sealing the team gold for the USA. She then collapsed in pain, the injury forcing her to withdraw from the individual competition. By the time she was carried to the podium to join her team-mates, she was a national hero.

She has not, however, made it easy on the world champions, who are looking to go one step better by winning the team gold for the USA on foreign soil.

"The gold is theirs to lose," Strug added this week. "They are phenomenal."

If they are to win, the USA will have to put personal battles aside in Beijing. In last year's world championships, the American girls took the team gold in Stuttgart with 184.4 points, less than one point ahead of China.

Aged just 15, Iowa's Shawn Johnson took the individual crown, which was particularly upsetting for her team-mate, Alicia Sacramone, who was caught on camera angrily staring at Johnson after the 20-year-old was relegated by the youngster to silver position on the floor, which she had won two years previously.

The other big star of the US team is Nastia Liukin - daughter of the 1984 Olympic gold medallist Valeri Liukin. Liukin is tied with Shannon Miller in having won the most world championship medals (nine) of any American gymnast.

It is, as Strug says, a phenomenal team, but so too is the Chinese line-up.

While the USA pipped China for gold at the 2007 world championships, the Chinese team claimed gold at the 2006 tournament with a score of 182.2 points (again less than one point separating the two nations).

The Chinese team is led by Cheng Fei, the 2005 and 2006 world champion on the vault and the 2006 champion on the floor.

In 2005 Cheng became the first gymnast to land a laid-out Khorkina: a round-off, half-turn on to the vault, then a 540-degree twist in the laid-out position. One of the most difficult vaults ever attempted by a female, it is now officially called the "Cheng".

China's most decorated female gymnast will be joined in the six-member team by Yang Yilin, Jiang Yuyan and He Kexin. Yang is officially listed as 15 years old, the other as 16 - but there have been claims all three are only 14 (which would contravene the rule whereby Olympic gymnasts must be at least 16 by the end of the year in which the Games take place).

The suspicion is that China will stop at nothing to top the medal table at these Olympics - a huge challenge given the USA took 102 medals in 2004, 39 more than China. And if they are to eclipse the US, gymnastics medals will be crucial, but playing at home is not always an advantage.

"So many people expect us to get gold medals and it really is a great pressure for us," says Cheng Fei. "Sometimes I find it hard to breathe or even cry under the pressure."