Using Katsu in a Constrained Space?

Katsu is being used underwater with aqua nuts. They're mimicking what would happen if we sent the spaceship to Mars. We've used them in submarines. Just doing some simple bicep curls, some hand clenches,. Some tricep extensions, squats by your bunk. It's an ideal way in a confined space that you can get a workout If you don't have the luxury of going down to gym or even walking around your, your neighborhood.