Spinward's number crunching shows just how difficult it could be to find space for crew, esp marines, to keep themselves in shape. A gym can be squeezed into a pretty small area though, (we have one set up in a 2.4 x 3.8m space with TV, Pelaton, weights and benches for two, equipment storage and room for two workout sessions at a time - which means there's a bit of unused wasted space when it's not being used). So if a barracks environment was designed with grav-bunks and shared freshers, if you could achieve an increased efficiency with space use in a 4dt stateroom for 4 pers, if you could increase the left over space from 1.6 per two staterooms to 3, then four staterooms would provide an area the size of what I have at home for that exercise area (and I'm certain marines would keep it much cleaner than we do!). Combine the live strength & endurance training with VR scenario sims and holo weapon-ranges (really just a step up from the virtual ranges used in NATO-level militaries today) and you could likely keep a section of marines in fair shape over an extended period of time.Or just common space for the ship's troops to exercise and train in at the very least, because there's very little of it in the FASA plans otherwise. (This is not uncommon on the early designs...)