These seem like cool expressions if they were applied to a masculine person, but if I heard those I'd feel insulted. I think they come from a time when being thicc was not a good thing. You don't want to be seen to be strong, muscular or curvy when the 'ideal' is a beanpole

(That said, I have always had thunder thighs and I still see it as a negative expression, but use it as a term of endearment now for mine)