[Barrin92]

>Forcing yourself to become a gym rat from being sedentary has unclear benefits regarding hard outcomes.

'hard' does a lot of work in that sentence. Try running up a few flight of stairs if you're sedentary compared to when you're in reasonable shape or try to take a fall if you're skinny compared with some more muscles on your skeleton, or just sitting in your chair for eight hours for that matter.

This is basically 'torture the data long enough until it tells you what you want' to finding an excuse to not hit the gym. Some studies on elderly people with vague exercise programs with probably no change in physique tells you nothing about middle-aged adults.