Mats Terweisch doesn't fit neatly into the founder archetype. He's not a dropout. He didn't pivot out of a hedge fund. He was chasing a spot on the US national rowing team when he accidentally stumbled into one of the most formative startup environments of the last decade - and that detour ended up being everything.

Today he's the co-founder of HYBRD, a YC F24 company built around the hybrid athlete movement: people who refuse to choose between strength and endurance, and who are quietly reshaping the fitness industry. But to understand why Mats built HYBRD, you have to start with where he came from.

Mats was born in France to two German parents and moved to the US as a toddler, settling outside Philadelphia. His father is a business school professor who studies operations management and innovation - which meant the dinner table was, effectively, a startup seminar.

"We were always talking about ideas he was seeing in the ecosystem, ideas the students were having. I just thought it was the coolest thing."

He went to Bates College, studied economics, and wrote a senior thesis on AI and healthcare data. For a while, he genuinely thought he was headed toward academia - a PhD, research, the long game. But there was a catch.

"To do well in the PhD world, you had to get very specialized on a very narrow subfield of economics. And I realized I'm a little bit more of a generalist - I like to learn about a bunch of different things and then try and piece them together. I think that skill set is much more rewarded in the startup world."

There's something worth sitting with in that observation. The academic path optimizes for depth. The founder path rewards synthesis. Mats figured that out before most people his age had even started.

After Bates, Mats took a research assistant job at Harvard - not primarily because of the career trajectory, but because it let him train. He had a serious goal: make the US national rowing team.

Harvard gave him the community, the schedule, and proximity to a world he was quietly getting drawn into. He was already an early WHOOP user - he'd seen another rower wearing one and got pulled into the product's orbit. WHOOP had just opened its subscription to everyday consumers after years of being a pro-athletes-only device. Mats was hooked.

Then came the locker room conversation that changed everything.

A training partner mentioned he'd just joined WHOOP - maybe 150 people at the time, early 2020 - and asked Mats if he wanted to come check it out. Two weeks later, Mats was in.

He started at what's now called WHOOP Labs, where his job was deceptively scrappy: strap people up with heart rate monitors, run them through experiments in what was essentially a retrofitted closet, and collect the physiological data needed to train WHOOP's machine learning models.

Then COVID hit. The lab closed. So Mats and his colleague did what any reasonable person would do: they packed a van and drove to Austin.

It was the kind of unglamorous, deeply user-immersive work that doesn't make it into pitch decks - but it's exactly the kind of thing that builds judgment. Austin, as Mats would later come to understand, wasn't just a convenient location. It was ground zero for the hybrid athlete community he'd eventually build for.

After about a year and a half at WHOOP Labs, Mats made another pivot that would define his trajectory: a desk neighbor explained what product management actually was, and Mats immediately recognized himself in the description.

He got the PM role. He worked his way up. He shipped features around strength training. And along the way, he was quietly building the team that would eventually leave with him.

One of the underrated lessons in Mats's story is about how founding teams actually form - not in accelerators or Slack channels, but over years of working alongside people in the trenches.

Every one of HYBRD's co-founders came out of WHOOP:

It reads simply when he says it. But what it really represents is years of trust built through shared work - the kind you can't manufacture in a team-building exercise.

Austin keeps coming up when Mats talks about HYBRD. And that's not accidental.

The hybrid athlete movement - training for both strength and endurance simultaneously, refusing the old binary of "runner or lifter" - has exploded in the last few years. It's visible in the rise of obstacle racing, Hyrox, CrossFit's continued growth, and a generation of fitness content creators who look nothing like the bodybuilders or marathon runners of the past.

HYBRD is building for that athlete. And Mats has been circling this community since he was strapping WHOOP prototypes onto rowers and driving a van around Texas. The insight isn't just market timing - it's pattern recognition from years in the field.

Mats's path isn't a clean narrative of "I saw the problem, I built the solution." It's messier and more interesting than that. A few things stand out:

The generalist advantage is real - but you have to lean into it. Mats turned down the PhD path because he recognized he was wired differently. That self-awareness opened a door. The startup world doesn't just tolerate generalists; it depends on them.

Early-stage companies are talent networks, not just employers. WHOOP wasn't just a job for Mats — it was where he found his co-founders, developed his instincts, and built the credibility to go do something of his own. If you're early in your career, the company you choose is the community you're joining.

Proximity to users is a compounding asset. The van trip to Austin wasn't glamorous. But thousands of reps with actual users built a kind of intuition that no amount of survey data can replicate. Mats carries that into HYBRD.

Trust takes years to build - and then it moves fast. The HYBRD founding team didn't need to spend months evaluating each other. They already knew how each other worked under pressure. That's a structural advantage that's hard to replicate.

If you're a hybrid athlete, an investor tracking the fitness tech space, or a founder curious about how early WHOOP built its data flywheel - Mats and HYBRD are worth following.

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