No it's definitely if you can look straight down and see your own dickI used to think it had a lot to do with aesthetics weightlifting numbers and running.
I cut a bunch of weight and started lifting weights at all kinds of rep ranges. I started making sure I could run two or three miles at a pretty quick pace for an average Joe (or 7 minute pace). I practice putting on a 35lb pack and being able to just walk it for 12 or 15 miles.
I considered this to be in shape. no blood pressure problems no health problems and enough performance not to be picked last.
None this really mattered for injury prevention though. Tweak the shoulder and couldn't work out the right way for months.
Now I'm hyperfixated on figuring out how to maintain health with injury prevention. And one of the best ways to do injury prevention is to dynamically load your body in safe ways so that it's prepared for heavy weights in all kinds of angles. Then when you're lifting that couch and forget not to rotate and look over your shoulder you don't hurt your back and slip a disc.
That's being in shape. Being able to Play a pickup game of football and not feel like you broke something the next day because you're over 30. Age without shoulders being rebuilt because you did too much pushing exercise and never learned to do a lot of scapular involvement. No knee problems because you learned how to jump and not just squat.
30 plus being in shape means consistent work output, a relatively low body fat, and no injuries ever.