September 20, 2026

Why we will never ask what your kid weighs

Most fitness apps want a number — weight, calories, a before photo. Here is why a training app for children should not have any of them, and what we track instead.

Open almost any fitness app and the first thing it wants is a number about your body. Weight, height, a goal weight, sometimes a photo. The app is built around that number, and everything it shows you afterwards is a comparison against it.

For an adult who has chosen that, fine. For a ten-year-old, it is a strange thing to hand them, and we do not do it.

What we ask for

A first name and the sports they play.

That is the whole record. No surname, no date of birth, no age, no photo, no school, no address, and no way for anyone — including us — to contact your child directly. The parent holds the account. Every email we send goes to the parent.

There is nothing in the product a stranger can reach a child through: no messaging, no comments, no public profiles, no leaderboard against other families.

What we do not ask for, and will not add later

No weight. No height. No body measurements. No calories, eaten or burned. No photos, before or after. No body-fat estimate, no BMI, no "goal physique."

This is not an oversight we are getting around to. It is the design.

Why

Two reasons, and the second is the one that matters more.

The first is that the numbers are wrong for children anyway. A child's body is changing for reasons that have nothing to do with training. Weight goes up during a growth spurt. It goes up when a kid puts on muscle. Tracking it during adolescence produces a line that mostly measures puberty, and then invites someone to draw a conclusion from it.

The second is that a number invites a comparison, and a comparison invites a feeling. Show a twelve-year-old a weight trend and they will have an opinion about it. They will have an opinion about the direction, and about how it compares to the kid next to them at practice. You cannot show someone a number about their body and also control what they conclude from it.

The upside of tracking it is small — none of it makes a kid better at soccer. The downside is a thing you cannot take back once a child has started thinking about it. That is not a close call.

What we track instead

Whether they showed up.

Which workout they did, and when. A streak that grows when they train and resets when they skip a day. Week and month dials so a parent can see the pattern without asking. Badges for consistency — a week in a row, a month, a hundred workouts — never for intensity and never for anything measured off the child.

The estimated length of a session, because "how long will this take" is a fair question. That is calculated from the drills in it, not from anything timed on the kid.

The honest version of the trade

Effort-based tracking is less satisfying than body-based tracking. A number that moves feels like proof. "Fourteen days in a row" is a quieter kind of evidence.

But fourteen days in a row is the thing that actually made them better, and the number on a scale was never going to tell them that. Consistency is the input. Everything a young athlete wants — a better first touch, being faster to the ball, not being the one who fades in the last ten minutes — comes out of turning up repeatedly, not out of monitoring a measurement.

So we track the input, tell them when they are doing it, and leave their body out of it entirely.

You can read exactly what is stored, and delete all of it in one click, in our privacy policy. It is short, and it is specific.