As a silvery stillness lingers over Waikiki Beach at dawn, a man plants his feet in the sand. With ritualistic focus he reaches for his petite partner, his left hand cradling her right foot, right hand holding her thigh. She leans onto his shoulder — and like a releasing latch, they both spring up, his outstretched arms raising her above his head. With a gymnast-like stance, she elongates her arms and points her toes.

His muscles contract and release and his weight shifts; straining, he holds her aloft for a few solid seconds. Then, as quickly as they’ve lifted into position, he releases her back down onto the sand. It’s a quiet dance of strength and grace, and complete trust in one another.

The two have ramped up their training in anticipation of the 2019 Pakaloha Tandem Surfing World Championship, scheduled at Kuhio Beach on Friday. The championship event is presented by the International Tandem Surfing Association, to which both belong.

They will repeat this morning exercise daily, as will a handful of other tandem surfing couples, as they prepare to compete at tandem surfing’s biggest event of the year.

>> More photos for ‘Tandem Surf World Championship’

The two continue a series of technically challenging lifts before heading to the water with a single longboard. Paddling out to the shore break, they will repeat their masterful maneuvers … but this time, on a moving surface, floating on the water, propelled by a wave.

Even from the shore, an especially tall silhouette can be spotted against the horizon as the two spring into breathtaking position.

The sets are gentle on this early Saturday morning in June, but ITSA co-president Tiffany Rabacal-Harper highlights the grit inherent to these extreme athletes:

“Tandem is seen as beautiful, in rolling, knee-high to shoulder-high Waikiki surf. Generally it is, but we have had championships in Makaha or even France where the conditions have been quite treacherous,” she notes. “It’ll be double overhead, with strong rip currents.

“Our guys are between 5-foot-6 and 6 feet, and then you add a girl on top who is 5-foot – that builds to over 11 feet. Their arms are in the air and the wave can still be another six feet above them.”

Her ITSA co-president is France’s Rico Leroy who will be in town for the championships, defending his current world title.

Also on the lineup are several Hawaii teams, and teams from South Africa and California, with the possibility of additional teams signing up.

Over the years, ITSA has held tour championships with up to eight events annually at various locations. However, the cost of travel comes from out of pocket, so single event championships have become the mainstay, with this year’s prize purse at $4,000. Host location has been shared lately between Hawaii and France.

Rabacal-Harper, a two-time world tandem title-holder, coaches teams in Hawaii, helping them practice and perfect the sports’ 72 sanctioned lifts.

Judges with binoculars sit high on scaffolding to watch the couples as the man takes a wave and lifts his partner into a series of four rehearsed poses. Scoring is based on surfing ability and acrobatics.

Longboard rules apply, so length of ride, wave choice, positioning and turns all come into play. Acrobatically, the judges are looking for excellent form. Falls result in deductions.

Men tend to have a strong surf background.

Women have to be at least half of their partner’s weight; they come from backgrounds that include dance, gymnastics, figure skating, contortion, aerial performance, acrobatics and cheerleading. They don’t need to know how to surf, but they do need to be strong swimmers.

“At first the girls might not be comfortable surfing, but they’re comfortable in the air,” says Rabacal-Harper. “When I first started, I’d rather be hanging upside down than trying to surf.”

It’s up to the couples how often they practice, both on solid ground and in the ocean. They juggle time around their busy working schedules. A gym in the University of Hawaii-Manoa athletic complex is open to acrobatics practice, including tandem, three days a week.

“The gym is the most contained environment I can give them,” says Rabacal-Harper. “We have falls occasionally, so in the gym there’s less distraction and a soft surface.”

The group includes stellar athletes like Hawaii lifeguard and champion waterman Kalani Vierra, or Lauren Oiye, who competed on the U.S. National Synchronized Swimming team, but welcomes anyone to come try the sport.

Women who compete tend to be in their 20s to 30s and men in their 40s to 50s. However, training for strength and endurance can make age irrelevant — as with Kathy Terada, who has been competing for decades and is in her mid-60s.

“We need mature men, because we can’t teach you the decades it took to get that surf knowledge,” says Rabacal-Harper. “The men are the ones picking the waves, doing the maneuvers, keeping their partner from hitting the board. They’ve got to be good watermen, making good judgment calls, not taking risky chances.”

“I took up tandem surfing because as I’ve gotten older, it’s harder to compete against the younger kids,” said longtime Waikiki Beach Boy Alika Willis.

“It’s also about the roots,” says Willis. “I’m just trying to continue our legacy at the beach.

“Back in the olden days, in Duke Kahanamoku time, the boards were way too heavy for the visitors to go out and enjoy the waves. So the beach boys would take the boards out for the visitors and surf with them. Later on some of the bruthahs, they’d take the girls and put them up on their shoulders. They got into some wild and crazy lifts. That’s where tandem surfing and competition started.”

A true waterman, Willis worked on Waikiki Beach, giving surf lessons and taking tourists out for canoe rides. He competes in all variety of water activities from canoe paddling to standup paddling — but finds tandem surfing to be one of the more difficult competitive watersports.

For some, the limelight draws contenders in. For others, tandem surfing is a way to connect with a longstanding tradition of Hawaiian watersports.

“On June 28, we will have some of the best teams in the world,” says Rabacal-Harper. “At least a couple of our Hawaii teams will give the reigning champions from France a run for their money – there’s a bit of a rivalry there.”

INTERNATIONAL TANDEM SURFING ASSOCIATION CHAMPIONSHIP

>> Where: Kuhio Beach, Waikiki

>> When: 8 a.m.-5 p.m. Friday

>> Cost: Free

>> Info: itsatandemsurf.org, ITSA on Facebook