The Minimalist Gym (Patreon)

There is a story called The Human Hamster over at the Metalbond website. It's an overall dark story that starts out depressing and gets worse, but the main feature is a prison that is designed to be as small as possible at any point for the given activities. It includes a mini-gym where the inmate is required to a certain rotation of sets, or he'll be punished.

There is a follow up to that story called The Bare Minimum Cage which is more interesting from a non-story point of view. The author gives a good try at designing a box that can allow for all activities for an inmate with the minimal room possible, while at the same time trying to make it as close to sensory deprivation as possible. It's basically a coffin where the top collapses in so much that you can rotate from lying on your back to lying on your front. But it can rotate into upright position and expand out to allow for standing, showering eating, etc. 

In this upright position the text describes how the floor is a treadmill, and you don't really have much of a choice to start running once it starts moving. Press against the sides of the box perhaps, but that is even more taxing. A second exercise is for the now ceiling to move down. Once low enough the inmate can start pushing it up, effectively squatting. By modifying the resistance and how low it will go per cycle the behavior can be modeled a bit to create the most effective squat program possible within the limitations.

When reading this I thought that this is exactly how I want forced exercises to be implemented. It's not a "do this or you'll be punished in a separate step". It's "do whatever you want, but actually doing the exercise will give you the least pain". Immediately I saw another opportunity with no modifications to the box.

The ceiling of the coffin when rotated upright is to the side of the inmate. That means the side of the box can already move in. For the inmate to push it out again requires arm, leg, and core muscles, so suddenly we have some sort of exercise for other muscles.

My second exercise thought was to get some jumping going. If there is a warning, e.g. a countdown sound, you could give the treadmill floor a bull fence electric shock. You'll very soon realize that standing on the floor when that happens is to be avoided.

Finally I realized that if the box rotates to the lying down position, then pushing the ceiling up would be another exercise for arms and legs. Perhaps not worth it, but free from additional implementation.

I don't really have a story in mind where I can use this. I want to use it for muscle building, and I'm not that sure how effective this would be since it's not very targeted exercises. But I guess it would be hard not to build some muscles if this is all you do.