Field Notes

How we build the coach — the thinking under the numbers.

We built a fatigue model. Then we tried to break it.

Most apps show you a confident number from a model that has never met you. We built a more honest one — and then spent weeks trying to prove it wrong before it touched your screen. It mostly failed. So we didn't ship it, and that's the point.

2026-07-16 · 7 min read

Sometimes we refuse your good news

Nail a personal best and most apps raise your FTP instantly. But the week you're flying is often the week your load is ramping hardest — and that's the worst moment to make every future target harder. So now and then, on purpose, we sit on the good news.

2026-06-24 · 4 min read

What kind of engine are you?

Two riders, the same FTP, completely different gifts — one wins the bunch kick, the other rides everyone off their wheel on the long climb. A single number can't tell them apart. The shape of their power curve tells them apart in a second.

2026-06-24 · 4 min read

Your FTP is a fresh-legs number

Hour one, you hold 280 watts and chat. Hour three, the same climb gives you 250 — same legs, same day. That fade is durability, it's as individual as your sprint, and your plan probably pretends it doesn't exist.

2026-06-24 · 4 min read

Your HRV isn't low. It's low for you.

Two riders can sit 30 points apart on heart-rate variability and both be perfectly fine. A single 'normal' line drawn for everyone tells you almost nothing. Here's why we read your HRV against your own history.

2026-06-24 · 5 min read

Why we don't chase your heart rate in Zone 2

Ride easy for long enough and your heart rate creeps up even though your effort hasn't changed. Here's why heart rate is the wrong thing to chase in Zone 2 — and what to anchor to instead.

2026-06-20 · 9 min read