Calories: a number nobody should trust
Every fitness screen loves a calorie counter. It is easy to understand, grows during the class, and looks like a reward. It is also mostly wrong.
Heart rate from a chest strap is accurate. Energy expenditure is not measured at all: it is estimated from heart rate, age, weight and a formula built on someone else’s body. A Stanford study of seven popular wrist devices (Shcherbina and colleagues, Journal of Personalized Medicine, 2017) found heart rate mostly within a few percent, while energy expenditure was off by 27% for the best device and 93% for the worst.
A number that can be wrong by a third or more doesn’t help anyone train better. It does make people “earn” their food, or feel that a hard class “didn’t count”. So we don’t show it — and your members won’t miss a number that was never true.
Points and leaderboards: the wrong race
Points reward time in high zones, so the fastest way to win is to stay near maximum heart rate as long as possible — exactly what a coach doesn’t want from a beginner in week one. A leaderboard turns people of different ages, fitness and goals into a race, and the people at the bottom are the ones most likely to quit.
Competition has its place in sport. A studio class is where people come back week after week, and that is what we build for. So there are no points and no leaderboards — not even as an option.
What members see instead
- Zone colour during the class: am I where this round wants me?
- % of my own maximum: comparable with myself, not with the neighbour.
- Time at high intensity after class: an honest measure of a hard session.
- Recovery over weeks: does my heart rate come down faster in the rests? Fitness you can feel.
Signals, not scores.
A score asks people to compare themselves with each other. A signal tells one person what matters for them right now — and leaves the decision to them.