POWAY —— Think synchronized swimming and an almost reflexive image pops into your mind: Esther Williams, gliding across the surface of a shimmering pool or diving through fiery hoops or somersaulting off a trapeze into a fog-shrouded lagoon —— ever smiling, smiling, smiling.

But this week, the public is invited to watch over 350 competitors ages 14 and over from eight different countries forego the fiery hoops and foggy lagoons, displaying instead the true grit and determination it takes to compete in the sport of synchronized swimming.

The U.S. Open Synchronized Swimming Championships at the Poway Community Swim Center boasts participants from the United States, China, Japan, Singapore, Canada, Chile, Puerto Rico and Great Britain.

All are prepared to debunk a nagging misconception that synchronized swimming is a snap.

"We have to give a good shout out to Esther, because if it weren't for her, we wouldn't be here," said Julee Lashley, coach of the event's host team, the Sweetwater Dolphins. "But just as technology advances, so does sports. And technically, we are nothing in comparison to how this sport started. These kids are trained and they are athletes."

Lashley described the sport as a combination of ballet, dance, gymnastics, water polo and figure skating. In the technical competitions, solo, duet, trio, and larger teams perform a set of exact movements, called elements, set to music that ranges from classical to pop.

According to Lashley, 50 percent to 75 percent of each routine is spent underwater, with the longest periods lasting a good 45 seconds. Couple that with magically holding themselves upside down, pencil-straight, spinning in place this way and that way in a set number of beats and in perfect unison —— the endurance and precision required is evident. Even their hands and fingers are splayed or pointed exactly the same way at precisely the same moment.

Routines last a little longer than three minutes for solo performances to just over four minutes for team events. Competitors are not allowed to push off from the bottom of the pool, and since they remain in the center of the deep end, the effect is akin to trying to dance a jig in a vat of Jell-O.

"It's crazy that people think the sport is so easy or so simple," said Kerri Browder of U.S. Synchronized Swimming and a spokesperson for the event. "You have to think of the endurance and the lung capacity. They spend most of their routines underwater. It's very, very difficult."

Musical choices set a tone for the choreography, which range from the whimsical to modern to classic. Colorful custom-made costumes create a watercolor painting in the pool, reflecting each routine's mood as well.

As with other more revered sports, the requirements to compete in synchronized swimming call for full commitment. The expense of travel, costuming, and endless cases of SPF 50 sunscreen can send shivers through a parent's pocketbook.

And, according to Lashley, the training is grueling.

"Most of these girls (train) anywhere from five to seven days a week, one, two, or three practices a day," she explained. Sometimes nine to 10 hours a day are spent working in the pool. But it doesn't stop when they pull themselves out.

"They do weight training, flexibility, yoga, Pilates, running, you name it," Lashley continued. "It all depends on if you're preparing for a meet, especially a meet of this magnitude."

The physical prowess of the athletes was not lost on Drew Mace, visiting from Alberta, Canada, and daughter Vanessa, 11, who has been involved in synchronized swimming for three years.

"It's like a ballet in water," said Mace. "You have to be so physically fit to do this. I mean, when you think how long they have to hold their breath underwater and do the moves that they do —— boy, they are really in shape."

And while Lashley laments a certain lack of community involvement in the sport, she knows that once people see synchronized swimmers in action, the perception that the sport is "just something pretty you do in the water" will change.

"Every sport has to fight its way up the hill," she concluded. "We're getting there."

The U.S. Open Synchronized Swimming Championships continue through Saturday at the Poway Community Swim Center. To attend Saturday's event, tickets cost $10 at the door. For the full schedule, check the Web site, www.usasynchro.org.