The sun is rising on this midweek day through pink-tinted clouds as early risers pad along Ala Moana Beach Park’s paved walkway area.

Next to a stretch of the path, Brenda Wong Yim, a 56-year-old fit enough to run a marathon on short notice, is warming up a group of about a dozen women and a few men — several of whom are older than 50 themselves — stretching on yoga mats and beach towels on a grassy patch.

"Stretch out that back. Think about form," Yim says in a tone that’s simultaneously perky and commanding.

Soon everybody is lifting a kettlebell, a cast-iron or steel weight used for core-strength training.

For the next 45 minutes or so, Yim, who has an extensive background in dance and a somewhat shorter history in sports, is in her element as she leads the free workout.

Yim completed her first Tinman triathlon at age 41, followed by her first marathon two years later. She went on to compete in Ironman events and, at age 50, was one of only four women to finish a grueling 100-mile endurance run organized by the Hawaiian Ultra Running Team, HURT. In addition, she has qualified multiple times to run in the Boston Marathon.

Despite those accomplishments, she’s still a bit surprised when someone refers to her as a gifted athlete.

"I don’t consider myself gifted. It’s a gift that I can do it," she says of her athleticism.

Growing up in the Makiki area, Yim started climbing trees and dashing around with neighborhood kids at a young age. She points to a scar on her right knee. "This is from childhood," she says, laughing. Whenever she got scraped up, she says, "I would not dare tell my mother" because that could bring the day’s playtime to an abrupt stop.

In an effort to add a touch of grace to Yim’s rambunctious ways, her mother enrolled her in dance class when she was 4 years old. Yim immersed herself in the art form so much that during her high school years she was exempted from PE classes due to her busy dance performance schedule.

Yim went on to dance professionally and teach dance for several years. After marrying Dr. Ernie Yim, a pulmonologist, the couple had six children. Yim shelved her dancing shoes when pregnant with their fifth child.

Years later, while juggling parenthood and work at her husband’s office, she signed up for a weekly step aerobics class where she added her own dance-inspired flourish to the moves. A triathlon coach who happened to be working out nearby spotted Yim’s high-energy exercising and offered to help train her for a Hawaii Tinman race, which comprises a 750-meter swim, 40-kilometer bike ride and 10-kilometer run.

Having no background in any sport, she had to ask, "What’s a triathlon?"

In the months that followed, Yim learned how to swim at Ala Moana Beach Park with help from a swim marshal; borrowed a neighbor’s bicycle for cycling around her neighborhood; and followed a novice distance running regimen. On the race day she had her share of bobbles but also had fun.

Plus, the experience help shape her "slow-boat-to-China" approach to fitness goals.

"You can do anything, just go slow," Yim says, adding that when she started preparing for the Tinman, she was excited to finish a 2-mile bike ride. These days, thanks to gradually pushing for longer distances, she might be up for a 200-miler.

Why does Yim continue to make an effort to stay active and set challenging fitness goals at a time when many peers are slowing down?

For one thing, she says, even though workouts can cause some short-term exhaustion, "you get more energy the more you do it."

Everybody hoisting kettlebells with Yim this morning agrees.

Yim began leading some of the Monday-Wednesday-Friday workouts at the beach park about two years ago in tandem with John Sarich, a part-time Hawaii resident who launched them as part of his Johnny’s Fit Ohana physical fitness programs.

Swinging her kettlebell around to the rhythm of an upbeat 1980s tune, Yim smiles and cheers the group on.

"Do it with zip!"

"Swing! Hup!"

"C’mon. Where’s that little bounce?"

While some of the tougher maneuvers prompt a few groans, there’s more laughter than grumbles. Everyone in the group appears to be having a good time.

The lively scene even prompts some passers-by, strolling along the nearby park path, to stop and try out a few moves.

For more information about the kettlebell workout, visit www.johnnysfitohana.com.