How Léon Marchand Trains (Phelps's Coach, and a Stopwatch Instead of a Heart Monitor)

Every other athlete in this series trains against a physiological number: lactate, power, heart rate. Léon Marchand trains against a clock. Swimming is the one endurance sport where heart rate is nearly useless, so the world's best medley swimmer, coached by the man who built Michael Phelps, organises his training around pace per hundred metres and how much rest he's allowed between reps. It's a different instrument for the same job, and it maps almost perfectly onto how an amateur should set swim zones.

The Bowman lineage

Marchand is coached by Bob Bowman, who guided Michael Phelps to 23 Olympic golds. Marchand moved from France to train under Bowman at Arizona State, then followed him to the University of Texas, and as of 2026 trains in Bowman's professional group in Austin. Bowman has called both Phelps and Marchand "aerobic animals," and builds his programmes on a large aerobic foundation with sharp, precisely dosed speed and lactate work on top.

Marchand's range is enormous: world records in the 200m and 400m individual medley, plus Olympic golds in the 200m butterfly and 200m breaststroke at his home Paris Games. The individual medley forces competence across all four strokes, which is its own argument for training breadth rather than narrow specialisation.

Intensity, not duration

Marchand has described the shape of a Bowman session bluntly: no session runs longer than two hours, but nothing in it is easy and the rest is minimal. In his words, "for every two hours of training, we have one minute to recover." The volume is real, roughly 35 hours a week with about 20 in the pool across two sessions a day, six days a week, but the defining feature is how little recovery sits between the hard efforts.

That's the mechanism behind Bowman's "red pace" threshold sets, where the rest interval is kept deliberately short (hundreds on around ten seconds' rest, two-hundreds on twenty) so the swimmer is forced to hold race-relevant pace under fatigue rather than swimming fast with generous recovery. As Bowman puts it, a 200 with a minute of rest simply isn't red pace.

Why swimmers ignore heart rate

Here's the part that transfers directly to you. Heart rate, the metric half this series is built on, barely works in the water. Being horizontal and immersed blunts the heart-rate response, and reading a monitor mid-stroke is impractical anyway. So swimmers use the one signal that is precise, immediate and always available: pace per hundred.

The amateur version of a swimmer's threshold is Critical Swim Speed, and you can estimate it from two time trials:

Swim a 400 and a 200 as hard as you can hold, feed in the times, and you get your CSS: the pace that approximates your swimming threshold. From there, every set has an anchor. Your easy swims sit a few seconds per hundred slower, your threshold sets sit right around it, and your fast work sits above it. It is exactly what Bowman does with Marchand, scaled down: hold a known pace on controlled rest, rather than "swim hard."

The discipline is the same one that shows up everywhere in this series. Most amateur swimmers grind every length at a vague moderate effort with lots of wall-hanging in between, which builds neither a real aerobic base nor real speed. Anchoring to CSS and controlling the rest fixes both.

Strength, not size

Marchand's dryland work is built around stability and functional power (bands, sled work, core) rather than mass, because added bulk hurts the buoyancy and efficiency that make a swimmer fast. It's the same principle the cyclists and runners in this series follow: strength as a support for the sport, not a bodybuilding project bolted on beside it.

2026

Marchand strained an adductor at the French Championships in late June 2026 and withdrew from the rest of the meet as a precaution after winning the 400 IM. His stated target is the European Championships in Paris in August, his first senior Europeans, where he has spoken about attacking his own 400 IM world record. By the time you read this that may already have happened.

What you can actually steal from it

• Set your swim zones from a stopwatch, not a heart-rate strap. Heart rate doesn't work well in water. Critical Swim Speed is the swimmer's threshold, from two honest time trials.
• Control the rest, not just the pace. A hard rep with long recovery isn't threshold work. Shorten the rest to make the effort honest.
• Hold a known pace, don't "swim hard." A number replaces guesswork, exactly as it does for runners and cyclists.
• Train breadth if you can. Medley forces all four strokes. Even for a specialist, varied work builds a broader engine.
• Strength for stability, not size. Support the stroke, don't add mass that fights it.

Marchand looks like the exception in this series, the swimmer with no lactate meter and no power file. He isn't. He's doing the same thing as everyone else, controlling intensity against a precise external number. His number just happens to be a time on a pace clock, which is the one you can copy for free tomorrow.

More in this series: Kristian Blummenfelt, Alex Yee, Jakob Ingebrigtsen and elite rowers.

Sources

Marchand's training under Bob Bowman in Austin is reported by SwimSwam; his description of session intensity is from Swimming World, and Bowman's "red pace" threshold method from Swim Spam. His 400 IM world record (4:02.50, 2023, breaking Phelps's 2008 mark) is reported by World Aquatics and his 200 IM world record (1:52.69, 2025) by SwimSwam. His 2026 injury and European Championships plans are reported by European Aquatics. Weekly-volume figures come from secondary reporting and are given as approximate.

Cover photo by Tanis Coralee Leonhardi, CC BY-SA 4.0, via Wikimedia Commons.