Depth

The competition rule is that the top surface of the legs at the hip joint finishes lower than the top of the knees. Pose estimation gives neither of those. It gives joint centres.

Which means the line is not where the joint centres meet. The top of the knee sits about four centimetres above the knee joint — roughly a tenth of a thigh — and the hip crease sits close to the hip joint. So by the time the two centres are level, the crease is already below the top of the knee and the rep is good. Every figure here is measured against that line rather than against level.

That offset is an anatomical estimate and it varies by person, which is part of why there are three answers and not two. Anything finishing within a twentieth of a thigh of the line comes back as too close to call. A tool that printed a confident verdict on a millimetre would be inventing precision it does not have.

Nothing here is in centimetres. Turning pixels into real distance needs a known length in the shot and there isn’t one, so every figure is either an angle or a fraction of your own thigh. Both survive the camera being closer or further away; neither survives it being off to one side, which is what the warning about the angle is for.

The video is read in your browser. The model and the code that runs it are served from this site rather than from Google, so using this does not tell anyone else that you did. There is no upload, and no copy of your lift anywhere but your phone.

It is not a referee. Three people watching the same rep from three chairs will disagree, and so will this.