Your joints are in good shape?
No, in Romanian this is really about the physical shape of the joints.
apparently yes - both, literal shape and general condition
see https://dexonline.ro/intrare/form%C4%83/21534 (2)
a fi în formă = to be in (good) shape
Not in a context like this. Only when referring to people. "Jucătorul este în formă "
The weirdest flirting tip I ever heard.
Oh I do hope someone will come up and tell me I have shapely joints! (Great elbows? Superb knuckles? )
Interesting! This must be one of those cultural differences. I had never heard about the good shape of joints before, other than in a medical sense, that is.