What to use for on spot indoor steps?

To make it very clear 

Playing for hours while holding a game controler = hand doesn't swing

Step on spot = for hours i lift one leg, put down, than the other, no distance, no "walking forward", no jumping, just steeping on spot

And YES, it works, i losed already over 25 kg via this AND diet (BOTH are needed, without one i maintain or gain weight) over a period of a year or so that is more realistic than me going to gym or other stuff that is TORTURE with 0% enjoyment 

Issues: garmin doesn't recognise steps done like this for obvious reasons ~ few hundreds of steps after hours 

Pseudo solutin: put on leg and easily 50000+ steps a day. This is a pseudo solution as it's annoying to wear the watch like this... So hoping there is an alternative. Aka

Request/question: is thare an activity that would recognise what i do while garmin is on my arm (no arm swinging)?