Women’s gymnastics is wildly popular in America.

For teenagers, the appeal is obvious; it’s the rare arena in which their peers are the best in the world. What motivates the rest of the population to watch athletes leap across a beam narrower than the diameter of a CD, or to watch young women slam their bodies in half while swinging from a pair of wooden bars? It can only be one thing: morbid fascination. Morbid because teenage girls are flirting with devastating failure; fascination because the sport requires immense fortitude.

Danger and difficulty define gymnastics. It is one of the few sports in which international officials deliberately increase the peril factor between Olympics.

Two of the nine Olympic judges are employed exclusively to calculate the difficulty of each routine and pre-determine its maximum score, known as a start value. Difficulty is so important that some routines – no matter how flawlessly executed – will never earn higher than a 9.7 or 9.8 because they are too easy. These days, a “10” no longer means perfection; it means dangerous perfection.

With difficulty comes pressure, particularly in the team event, which begins Sunday with a new format. In the past, a nation was allowed to discard its worst score on each apparatus. Now every score counts in the medal round. With the hopes of an entire nation riding on each teenager for a precious few seconds, someone will inevitably crack. One only hopes she’s not from home.

In all, there are four apparatus in women’s team gymnastics: beam, bars, vault, and floor.The most entertaining and popular is the floor exercise – perhaps because it dissipates the tension as athletes flip, skip, tumble, and run across a springloaded carpet while music plays in the background.

The team event was long dominated by the Russians, who won 10 of 11 gold medals between 1952 and 1992 (the gap came in 1984 when the Soviet Union boycotted L.A.) Then came Kerri Strug’s onelegged landing off the vault at Atlanta in 1996, which allowed the U.S. team to win an unexpected gold medal.

Despite the hype surrounding the U.S. squad after winning the team gold at the 2003 World Championships, the 2004 Olympians are a slightly different group that does not include a runaway favorite on the floor. Carly Patterson (Baton Rouge, La.) has the difficult maneuvers, but Courtney McCool (Kansas City, Mo.) is more expressive and artistic. Each will contribute greatly to the composite score, however.

Athens marks the Olympic debut of all six women on the U.S. gymnastics team. In addition to Patterson and McCool, both 16, they are Mohini Bhardwaj (25, Los Ange les), who recently received financial backing from Pamela Anderson; Annia Hatch (26, West Haven, Conn.), an ace on vault who who won bronze for Cuba at the 1996 World Championships but was left off the Atlanta Olympic team; Terin Humphry (18, Blue Spring, Mo.); and Courtney Kupets (18, Bedford, Texas.)

Perhaps the most beguiling gymnast is Svetlana Khorkina, 25, the pillar of the Russian team and the sport’s reigning diva. She helped her nation earn the past two silver medals in the Olympic team event as well as two individual gold medals on bars and a silver on the floor in 2000. Since then, she has taken acting lessons and performed in a Moscow play by Henry Miller.

Equally captivating is China’s Zhang Nan. Eighty-four pounds of pure radiance, Zhang is also the most versatile member of the Chinese team and most likely to emerge as the darling of Athens.

Five nations (China, Romania, Russia, Ukraine, and the U.S.) will be in the hunt for the team medals. The U.S. and defending Olympic gold-medal winner Romania are co-favorites because of their depth. Ukraine is solid but slightly less spectacular. Russia has a few stars from previous Games but is otherwise rebuilding; it could easily bend under the weight of its heavy legacy. China’s task will be to overcome inconsistency and nerves.

Overall, the competition is expected to be so close that one disastrous performance on a single apparatus could spoil everything. Will the winner be the group that outshines the rest, or simply the survivor of the fewest catastrophes? Let the rubbernecking begin.