Reflections Interview: Olivier Delfosse — From Pool Records to River Wins

Interview by Ben Lane

When Olivier Delfosse talks about swimming, the story stretches from a 1970s Brussels pool to the weed-choked bends of the Ebro and the long blue runways between Capri and Napoli. At 62, he still trains to win—not out of arrogance but out of appetite. “It’s just in me,” he says with a shrug. “Since I was five, I wanted to go fast. Faster than before.”

We spoke about growing up in the lanes, turning to open water, and why the last word at UltraEbre belongs to patience, rhythm, and the river itself.

“Faster than before”: the pool years

Olivier: I learned breaststroke first, then crawl, then the club in Brussels in 1971. Very quickly, I needed to go fast—faster than the others. We changed clubs to find better training—American-style sets in the late 70s—and by the end of that decade we were Belgian champions in the 4×100 m and broke the national record. We held titles for four years.

Life took over in the 90s—marriage, children, building a house, work—and I stopped. Then in 2008 an old friend called: Masters Worlds, a relay. We finished second. I told him, If I return, it’s for everything—200 free, 200 IM, 400, 800—backstroke, breaststroke, fly. I came back, raced European and World Masters, and won a lot in my age group.

By 2013, after a European Championship, I walked out of the pool exhausted and knew: I needed a different challenge.

Open water, open horizons

The pivot came with a promise to a friend who wanted to cross Gibraltar but needed a partner. “He had no fingers,” Olivier says simply. “We trained. We crossed. It was amazing—and it was the start.” From 2015 onward, he left pool competition behind (he still uses it for training) and embraced open water—early on with Oceanman, when fields were still small and experimental.

Between the ages of 50 and 59 he won “every race I made”—5 km, 10 km, even 25 km—overall or in category. The distances grew: 10 became 15, then 25, then 30. He speaks of Capri–Napoli with affection: one win in an open category, a second elite attempt a few months later that ended short. “It happens,” he smiles. “That’s open water. You never know what the sea or your body will do.”

The UltraEbre habit

Olivier is a regular at Spain’s UltraEbre (30 km). He has won it and also finished second several times. To him, the race has a distinct personality: a generous first half, a stubborn finish.

Olivier: The early kilometers are fast—the river gives you a gift. But near the delta, the water grows heavier, the wind can ruffle the surface, and you feel you are not moving. That’s UltraEbre’s truth: the race starts when you feel slow. Rhythm wins.

He’s candid about the chaos too: “Vegetation,” he says, forming a rope with his hands. “A huge surface of weed. Around the neck, the shoulder, the knees. Impossible to pass. My kayaker and I look for a way. A local swimmer knows and slips by. He wins. You learn; you come back.”

Training at 62: rhythm, not bravado

Olivier’s preparation is unsentimental: winter is for rest and gentle movement; the build begins in January. He still cycles and lifts early in the block to “wake up the body, lungs, and heart,” but he gradually pares back gym work as swim volume climbs. “Musculation helps sprint,” he says. “For long distance, rhythm is the muscle.”

A typical build looks like this:

• January–February: 2–3 pool sessions a week (3–4 km each), plus light strength and bike work.
• Spring: swim most days, mixing 4–6 km aerobic sets with technique and pull; gym fades.
• Final 8–10 weeks: one 10 km session every week, aiming for 2½–3 hours of continuous, disciplined pacing.

The will to win—and the respect to finish

Olivier’s mindset is frank: he lines up to win. That clarity shapes his choices—where to draft, when to push, how to protect stroke length. But he’s also quick to widen the lens.

Olivier: In mass-start races you may have 200–400 swimmers. Maybe 20 want to win. The rest are there for the distance, the personal challenge, the first 10 km, the cold, the crossing. I finish a 14 km lake race in three hours; some finish in six. At the podium, you see the last swimmers arrive—children running to their father, a superhero. The first and the last—it’s different, but it’s equally important. Same story, different pace.

How he builds the “finish”

On the hard days, Olivier doesn’t bargain with the distance; he replaces it with tasks. “I break the swim into stages and defend the rhythm,” he says. Fix the line, lengthen the stroke, keep feeds compact, breathe without panic. If the field surges, he doesn’t chase blindly; if the weeds arrive, he searches for clean water. The mental cue is simple: win the next section.

He also trains the feeling of the finish. In long sessions he simulates the Ebro’s arc—cruising early, then deliberately tightening the screws in the last hour when fatigue is honest. “You want to meet that feeling already once or twice a week,” he says. “Then, when the river asks for it, your body answers.”

Practical notes for UltraEbre hopefuls

• Give yourself six months. Start modestly, then aim for consistency.
• Build a weekly long swim (10 km) in the final 8–10 weeks, holding a sustainable metronome pace.
• Use variety to protect the brain: breathing patterns, short blocks of backstroke, pull+paddles.
• Draft with intent in the early kilometers; the river will sort the field later.
• Expect obstacles: vegetation rafts, wind ruffles. Don’t let five messy minutes steal the next thirty.
• Train your feeds and keep them short. (Olivier’s own intake is minimal; he stresses this is highly personal and must be practiced.)

Why he’s still here

The competitive edge remains—he won UltraEbre one year, finished second two others—but the motivation is bigger than a place on the results sheet. It’s the quiet arc of a season: winter softness, spring sharpening, summer confidence. It’s the knowledge that the first half of UltraEbre is a gift and the second half is a test—and that both are the point.

“You never know what will happen out there,” he says. “That’s the beauty. You prepare so well you have no fear—only the question: Can I catch the guy in front? And if not, can I still make my best rhythm? That’s the win I can control.”

He pauses, then grins. “Also, the family at the finish. That feeling never gets old.”

Olivier Delfosse is a France-based Belgian open-water racer and former pool national record-holder. A regular at UltraEbre, he builds seasons on disciplined rhythm work and weekly 10 km sets. At 62, he still lines up to win—while championing every swimmer’s finish, first or last.