Bone and muscle loss in the space are caused by lack of gravity. We're terrestrial animals, so our skeletal system growth is contingent on NEEDING one. No gravity pull, no need for bones. This has nothing to do with any nonsense about "radio signals from Earth". 

 hmm ok i know nothing, first of all

but id say there's prolly some nuance somewhere. 
there's always nuance and some interaction. 

i dont know where or have much interest in finding it for this specific topic, but I'd dare to bet on it fr fr