The trouble with #BeatSaber is that it's decpetively hard on shoulders/upper back and wrists. In my case, it's also hard on my foot as I shift my weight about to help in reaching far notes and dodging walls. (The Index is set up in Standing Only config as my place is too small for moving around.) It is possible to play sitting down on an armless chair, but it's actually harder that way and strains the torso more. It's one hell of a reminder that I'm not a teenager with infinite muscle endurance any more.
All this means I can't just stand there and play it for 12 hours straight