A kids workout that watches back

Most searches for a workout for kids end on a video: a cheerful instructor, a countdown, and a living room where one child copies every move while the other watches from the sofa. Kids workout videos and exercise videos for kids are easy to put on and impossible to check — the video carries on whether anybody moves or not.

Hopla is the other kind. It is not a video; it is 35 free movement games where the webcam is the controller. The browser tracks the kid's arms, legs and head on your own device, and the game answers what the body does: jump and the ninja clears the bamboo, march with the knees high and the climb goes up, punch fast and the straw targets burst, run on the spot and you outrun the fire spirit. Stop, and it stops. That is the part no workout video can do.

A ten-minute kids workout

A round is one minute, so a workout is a handful of rounds back to back. Jump & Duck for the legs and the heart rate, Bamboo Climb for high knees, Big and Small for stretching up tall and curling down to the floor, Power Smash for fast arms, and Race the Flame to finish flat out. Do the set twice and that is ten minutes. Each game has four ranks — Rookie is very forgiving for a four-year-old, Pro and Legend step it up, Master is a proper workout for a 12- to 14-year-old — and a better round earns a better medal.

Points are never taken away, so a kid who runs out of breath just scores more slowly; nothing punishes them for it. Two kids can work out side by side, each on their own rank and sharing one score, so siblings of different ages train as a team. Free, no account, no download, no equipment beyond a webcam and two metres of floor — and the camera image is processed in the browser and never leaves the device. More on the game side of it in exercise games for kids.