The greatest athletes are those who compete against themselves. They’re their own biggest rivals, and they don’t need to be pushed by others. Instead, these phenomenal competitors are motivated by their own self image, by their own mind, and by their own desire to achieve the seemingly impossible goals they set for themselves.


“We’re going to try to walk five miles underwater,” Don Tran says. He’s driving, but even with his eyes on the road, there’s a glimmer of excitement in his facial expression. He hasn’t even mentioned the fact he’ll be carrying a 45-pound rock while he’s underwater. Don is straightforward and direct in his speech, but there’s something more when he talks about being underwater. Add in the element of a challenge and Don is buzzing. Add in his partner in this Feat of Strength, Kaj Larsen, and they’re both feeding off of each other’s energy.

 “We were going to do one mile, but we did some training on our own and figured we could do a mile easily alone in about an hour,” Don says. Naturally, they wanted more of a challenge. Kaj and Don are both at home in the water; Kaj is a combat veteran Navy SEAL (his father and grandfather having served in the Navy and the Marines, respectively) and Don is a former Marine Raider and Military Water Survival Instructor.

Still, no matter who you are, a five mile underwater rock carry is downright superhuman. It’s the inherent lingering danger that keeps them from leaning all the way into the thrill of what’s to come. These men know water, but knowing it so well means that they also intimately know every danger. When they talk about this challenge, there is a deep reverence for the ocean itself, both its beauty and its power. To complete this feat, they’ll have to override the most basic human instinct - breathing.

It’s why they found it so important that this Feat of Strength be completed with two people. “Always have two people when it comes to being underwater. Always,” Kaj makes clear early while in talks with the Ten Thousand team.

In addition to relying on one another, Don and Kaj have the legendary Northshore Lifeguards on their team which gives them the extra confidence to tackle this challenge. They know the water will be their biggest obstacle in this feat, but if all the cards fall into place, knowing the ocean could be their biggest asset, too.



Both men possess a specific set of skills, honed specifically for military duty, that will be harnessed to push their bodies and minds to new limits for this rock carry. Kaj and Don’s extensive underwater training is what brings completing this feat into the realm of possibility, otherwise this would be a “do not try this at home” kind of feat. They were both drawn to the water long before active duty, so it makes sense their connection to it would remain strong after, as they use their skills to raise awareness to a cause near to them.

Kaj and Don decided early on that this feat would be dedicated to Force Blue, a nonprofit that seeks to aid the lives of combat veterans returning to civilian life and work towards preserving and restoring the ocean. Much like Kaj and Don, many other veterans have spent hours of their lives sharpening underwater skills that originally seemed niche and nontransferable. Force Blue gives these veterans a new purpose for their existing skills, whether it be working restoring coral reefs after hurricanes or rescuing sea turtles. Giving these veterans a renewed sense of purpose can be life-changing for their mental wellness. Force Blue is equal parts about mental wellness and ocean conservation, knitting the two together so that the veterans can work in tandem with nature. They call it the “ultimate win-win” uniting the veteran and conservation communities to foster empathy and compassion.

It would be Force Blue’s mission that both men would think of with each and every step across the ocean floor.



The first time the Ten Thousand team checked in with Kaj, he was on a boat, quite literally at home on the water. Take one look at his social media and you’ll see him, fins and goggles on, exploring the oceans. Don is a cofounder of Deep End Fitness, an in-the-water functional fitness group workout. He’s fostered a whole community around pushing their limits, focusing on swim technique and deep breathing. With the Deep End Fitness community, Don has plenty of people to support him while he plans out specific workouts in addition to his existing pool workouts.

“I’ve been doing a lot of dumbbell carries in the water. The current plan is to do 25 meters at a time, about 17 steps, because without markers in the ocean I won’t know exactly how far I’m going, I’m going to come up and do 8 full recovery breaths and tap out with Kaj. I’m trying to do a mile a week by myself and see how far I can go. It takes about an hour but some weeks longer than that. So that’s the plan.”  

Kaj’s prep looks similar and is equally as daunting. He’s got a community of big wave surfers (who he credits as being the first people he saw doing underwater rock running) helping him train, always a buddy system. He’s got surfing great Laird Hamilton and Luca Padua in the pool with him and overseeing his training sessions.

Kaj and Don are both calm and collected as they detail what sounds superhuman. It is a testament to how fitness can translate outside of the workout - being underwater with such frequency requires you to be calm and collected under pressure, mental and physical acuity working hand in hand. Their ability to remain calm in the face of the near impossible is a skill they originally sharpened out of necessity. It makes it all the more thrilling when their excitement gets the better of them when they talk about the final event in Hawaii, both men grinning at the prospect of even trying to complete this feat.

Soon, all that’s left is to go to Waimea Bay.



When June 18th finally arrives, the weather in Oahu could not be more perfect. There are clouds in the sky, but they never block out the sun. It’s picturesque; nature is showing off. The water is rippling with reflections on the white sandy floor of the bay. It’s an invitation.

Kaj and Don are geared up in Ten Thousand Set shorts and Third Eye goggles. It’s all smiles and adrenaline as the final preparations are made - the ocean floor measured out, sunscreen slathered across skin, the 45-pound rock handed over from the lifeguards to Kaj and Don.

They start the rock run in a buddy carry, something they’ll return to multiple times during the feat. While Kaj carries the rock, Don holds onto his shoulders. It’s a constant reminder that you’re not walking the ocean floor alone, a grounding touch. At the top of the feat, it’s Kaj whose recovery breaths aren’t as restorative as he wants them to be, but he leans on his training and on Don to keep moving forward with hours to go.

Kaj and Don start the day with a small crew; a group of photographers and three lifeguards from the North Shore Lifeguard Association to make sure that everything is documented and if something goes wrong, there’s trained professionals to intervene. Lifeguard Mo Freitas hovers above them on a jetski from the moment they begin. As the challenge progresses, however, the crowd grows quickly. The waves are calm enough to swim and snorkel, and Hawaii is open for tourism. Waimea Bay attracts locals and tourists alike, and with the crew and equipment in the water and on the beach, Kaj and Don stick out. Beachgoers start to gather, wanting to be a part of the feat.  

They’re about halfway through when Don starts to feel uncomfortable. It’s fatigue settling in, physical exhaustion settling into the intercostal muscles that execute the mechanical aspect of breathing. The human physiological response to both physical and mental fatigue is pulling Don in two different directions. His fight response tries to speed up his heart, asking him to get more oxygen to all areas of his body. The flight response asks him, “how easy would it be to stop right now?” It’s only human - the sympathetic nervous system doesn’t care that they’ve got a task at hand, it’s just trying to keep them alive.

It’s also at about the halfway point when Kaj starts feeling comfortable, the recovery breaths feel deeper and more restorative. He starts to live comfortably in a parasympathetic state, a lowered heart rate and a lower need for oxygen. Even though they’ve been at this feat for about three hours, the movement in both his lungs and body begins to feel second nature. It couldn’t be more perfectly timed. In the same way that Don held both of them down for the first half, Kaj holds them down for the second half. They don’t quit.  

Six and a half hours from the time they began, ending in a buddy carry, the two men and a 45-pound rock cross a roped-out finish line, coming above water to celebrate with the team and the spectators.

The entire team takes underwater pictures. In the months to come, huge waves will carry surfers from the water to the shore with speed, but for now, the water slowly breaks against the shore. The ocean moves around them, unbothered, as if nothing happened at all, or even more - like Kaj and Don’s strength blend effortlessly into the power the ocean carries every single day. It’s a reminder at the end as to why they embarked on this feat in the first place - the need to take care of the water that sustains so much life on this planet, the strength and beauty around us at all times that we can all do more to appreciate.

Don & Kaj's Kit

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