Um, no they do not suggest any such thing. A person is not necessarily going to get injuries from slamming another persons head into the ground. Nor do you necessarily get injuries from hitting someone.
But where is the proof that Zimmerman ever attempted to defend himself with less than deadly force? I don't think that bodes well for Zimmerman. It seems his only "defensive" act was to shoot Trayvon.
This is absolutely why you don't want armed doughy wannabe's walking around acting like they are cops.