Stephen Panzarino dives into his fitness routine at the Lakewood Ranch YMCA with a splash at 5:45 a.m.

He's on the Sarasota YMCA Sharks Masters Swimming team, a club of adult swimmers. Members range from serious competitors who travel to national meets to people who just want to get into better shape by practicing with a group of like-minded water buffs.

Panzarino, a 50-year-old architect, started swimming with the Sharks last December after his 16-year-old daughter, Sidney, basically told him to put up or shut up. Sidney is on the Lakewood Ranch High School swimming team.

Dad talked a lot about competition. Daughter told him that he really needed to do something about it.

"I just turned 50 and said, 'OK, let's get back into the pool,'" Panzarino said.

He found a place to "just do it" through Masters Swimming.

In London, Olympic U.S. swimmers Michael Phelps and Ryan Lochte have shown how the human body can propel through water at an astounding rate. In pools throughout the country, including the one at the Lakewood Ranch Y, the Masters swimmers show how swimming is a lifetime pursuit.

The Sharks are part of U.S. Masters Swimming, a national organization founded in 1970. More than 700 clubs are now affiliated with U.S. Masters, according to its website. Their members range in age from 18 to 100-plus.

"I was a competitive swimmer from middle school through college," said Panzarino, who first joined a swim team after watching swimmer Mark Spitz win seven gold medals in the 1972 Olympics.

Today, after seven months of swimming with the Sharks, Panzarino has regained zest and lost 20 to 25 pounds. Sidney joins her dad for the early-morning workouts. They swim laps in the same lane.

"I feel that I'm in as good of shape as I've ever been," said Panzarino. "I'm not as tired as I used to be."

Locally, other Masters teams include the Original Sarasota Masters, which practices at the Arlington Park Aquatic Center. The Bradenton Masters suspended group practices at the G.T. Bray Aquatics Center several years ago after the team dwindled in numbers, said its coach Ted Bennett. He now offers one-on-one training.

The Sharks call their main location the "Shark Tank," the pool at the Selby Aquatic Center in Sarasota. To accommodate folks who live or work in Manatee County, practices are held four times a week at the Lakewood Ranch Y.

A core group of swimmers -- about 10 to 15 -- show up at the Lakewood Ranch Y pool to work out from 5:45 to 7:30 a.m. Mondays, Wednesdays and Fridays, and from 7:30 a.m. to 9 a.m. Saturdays.

Coach Ed Mench swims with the Lakewood Ranch group and provides the workout-of-the-day, a series of timed laps and interval training.

"First and foremost, it's just an excellent way to stay in shape," said Abby Schweigart, who works in sales and lives in Bradenton. She joined the Sharks last spring and swims at Lakewood Ranch.

Schweigart is a triathlete and plans to compete in a Half Ironman in Miami, where she will have to swim 1.2 miles. She swims with the Sharks to speed up her swim times and get coaching from Mench.

"I'm definitely getting much faster training with them," she said.

Schweigart swam on teams from kindergarten through high school, but "you forget little tips to be a better swimmer," she said.

Although many Shark members love to compete -- a group went earlier this summer to a national competition in Omaha, Neb. -- entering meets isn't necessary to be on the team.

There are Shark swimmers only interested in keeping fit, said head coach Rick Walker, who leads workouts at the Selby Aquatic Center. It's easier to stay motivated when working out with a group instead of swimming alone, he added.

"A lot of people think swimming is the best workout ever," said Walker.

"Obviously, you aren't pounding your feet. It's a non-impact sport. Not only are you working all your muscles but your aerobic system is getting a huge workout," he said.

"It's really the fountain of youth, in my opinion."

The team's best example is Bumpy Jones, a 79-year-old member who swam in the 1952 Olympics.

The Sharks hold an annual Bumpy Jones International Classic in honor of the team's most famous swimmer. The 2012 Classic was held in June at the Selby Aquatic Center.

Panzarino registered for the race, his first in decades. He swam the 50-meter breaststroke and 50-meter freestyle and came in first in his age group.

Susan Hemmingway, Herald health correspondent, can be reached at shemmingway@hotmail.com.

MASTERS SWIMMING

The U.S. Masters Swimming website offers a wealth of information for fitness swimmers. The site also lists teams in Florida and throughout the United States. Visit www.usms.org.

Local clubs

n Sarasota YMCA Sharks Masters: Group swims at Lakewood Ranch YMCA, 5100 Lakewood Ranch Blvd., and Selby Aquatics Center, 8301 Potter Park Drive, Sarasota. Information: Coach Rick Walker, 941-346-7946 or www.sharksmasters.org.

n Bradenton Masters: G.T. Bray Aquatics Center, 5502 33rd Ave. Drive W., Bradenton. The club isn't offering groups, but individual coaching is available. Information: Coach Ted Bennett, 941-713-7479.

n The Original Sarasota Masters: Arlington Park & Aquatic Center, 2650 Waldemere St., Sarasota. Information: Coach Peter Hegwein, 941-924-6908, or www.sarasotamasters.wordpress.com.