PHILADELPHIA -- Shawn Johnson rumbles across the floor exercise mat like a sparkling bowling ball gaining speed and power until she reaches the corner and throws herself into a sonic boom of flips, twists and a forceful landing.
She offers a smile and swings her shiny ponytail.
Across the way, Nastia Liukin uncoils her legs and lifts herself onto the uneven bars.
In the next two minutes she twirls and twists herself into pretzel positions, doing one-handed circles and swinging from the top bar to the bottom bar with three breathtaking release moves before finishing with a double twist and landing lightly onto toes that have been nothing but pointing straight.
She bows her head slightly to the wild applause.
It is these two girls -- Johnson, 16, from West Des Moines, Iowa, and Liukin, 18, from Parker, Texas -- who appear poised to become two of the biggest Olympic stars and rivals for one of the most coveted Olympic gold medals in the women’s gymnastics all-around.
Tonight at the Wachovia Center they will display their gymnastics strengths and differences in the first of two rounds of competition at the U.S. Olympic trials.
Based on results over the last two years it is all but certain, barring an injury, that Johnson, the two-time defending U.S. champion and defending world champion, and Liukin, the only woman to beat Johnson in an all-around competition in two years, will have earned the two automatic spots to the six-woman Olympic team.
While Johnson and Liukin ache to win their sport’s ultimate prize, there is no chance they will turn their rivalry into Tonya-Nancy.
It was during the lead-up to the 1994 Winter Olympics when figure skater Tonya Harding allegedly participated in a plot to use a bar and whack the knee of rival skater Nancy Kerrigan at the U.S. National Figure Skating Championships, which served as the Olympics trials.
Kerrigan ultimately won a silver medal, but the scandal had dominated the Lillehammer Olympics because Harding was allowed to compete, adding drama that brought both record embarrassment and TV ratings to the sport.
It seems unlikely that Liukin, who is 5 feet 3 and 100 pounds, or the 4-9, 90-pound Johnson are plotting anything so dire.
Last week when Johnson was forced out of her home gym because of flooding, Liukin text messaged her, expressing concern and wishing Johnson luck. Johnson sent her thanks and signed her text, “Love, Shawn.”
“Shawn and Nastia are as different as can be,” says teammate Alicia Sacramone, who was captain of last year’s world gold medal-winning team. “They are different ages, they care about different stuff, their gymnastics is so different but ultimately they want the U.S. to do well. There’s no way we’ll have a Tonya-Nancy here.”
Kim Zmeskal, who was an Olympic gymnast in 1992 and is a former world champion, has watched Johnson and Liukin practice every month under the watchful eyes of U.S. team coordinator Martha Karolyi at Karolyi’s ranch near Houston.
“Of course the girls watch each other,” Zmeskal said last month.
“You can see out of the corner of their eyes, every month when they first arrive. They want to see what the other one is doing now.”
Liukin, who was born in Russia, has been coached and trained by her father Valeri, who was a gymnast for Russia, and her mother Anna, who was a rhythmic gymnast on the Russian team.
Many coaches considered Liukin the best American gymnast four years ago before the Athens Olympics, but Liukin was too young to qualify and fellow Texan Carly Patterson won the gold.
Since then, Liukin has suffered through injuries, growth spurts and watched with quiet frustration as Johnson arrived on the senior scene last year with a dramatic rush of wins at the Pan American Games, the national championships and the world championships.
And while Liukin was groomed from toddler-hood for gymnastic stardom, Johnson tumbled into the sport accidentally -- mostly because she was breaking furniture in her Iowa home while somersaulting off the cabinets.
Her coach, Liang Chow, came from his native China with a dream of opening a gymnastics academy and he did -- opening his own academy in West Des Moines, Iowa. His careful grooming of Johnson included sending a videotape of his young protege off to Karolyi.
Johnson has come of age at the perfect time for an Olympian.
At 16 she is still fresh and has avoided the kinds of stress fractures and dislocated knees and shoulders that come with being a veteran in the sport.
Liukin is proud that after battling a foot injury for much of last year, she has beaten Johnson at one competition this year -- the Tyson’s American Cup -- and finished a close second at the national championships.
“They are such totally different gymnasts,” Zmeskal said. “Shawn is great on the power events, the floor and the vault. Nastia is so good on the uneven bars and balance beam. It almost seems as if you like one or the other.”
When asked if she could import one of Liukin’s qualities into her own gymnastics, Johnson had a quick answer. “I’d love to do her uneven bars. Her one-handed swings, wow.”
Liukin has her favorite Johnson move too. “She’s doing two and a half twists on her vault,” Liukin said. “I’d like to have that.”
And they both want one other thing. An Olympic all-around gold medal.