"He lost control of his legs."
Translation:Él perdió el control de sus piernas.
It is my understanding that in Spanish, one does not use "el posesivo" (in this case - sus) when talking about parts of the body. instead one should use the relevant definite article - in this case "las". I have reported this but if anyone thinks differently, please let me know.
I was naturally using ...Control de las piernas... too. But the real question is why do you have to use "el control" why can't you just say "control"
My original response: El perdio control de las piernas
Correct response: El perdio el control de sus piernas
"control" is an abstract noun, so it's not surprising Spanish would prefer using a definite article (consider "la responsabilidad," "el amor")
Use of the article is not universal, but very strongly favored: http://bit.ly/2tqCVv7
It'd be great if a native speaker could clarify further.