The evidence quite clearly shows Zimmerman followed Martin.
Yes, he did follow Martin. Briefly, and only in the sense that he went in the same direction Martin had gone in order to maintain a visual. He went to the next spot which would permit him to view southward, and hopefully see which way the person ran. Of course, when he got there he didn't actually see where Martin had gone. Either because it was dark, or Trayvon hid somewhere, or Trayvon just got too far south before George got to the "T" junction, or some combination of these things.
He didn't pursue him, or attempt to close the distance and come into direct contact with him. That's what most people wish to smuggle in with the word "follow" when they say it.
But yes, he did briefly follow Martin. He may even have picked up his pace a bit, but I do not think there's any reason to believe he "ran after" Trayvon.
Wind noises =/= running noises. And I hear no strain in GZ's voice when he says "Yeah" and "Okay" to indicate he's exerted himself at that point. It was the sound of the wind which tipped the dispatch off to the fact that George was out of his truck, not the sound of any heavy breathing, huffing and puffing, or footfalls. None of those sounds are present. I'm not saying wind and running can't both happen, of course they can. What I'm saying is, one doesn't indicate the other.
I'm basing most of what I'm saying here on George's testimony, which I haven't seen any good reason to disregard yet, because it seems to me to fit the evidence quite well other than a few minor issues which I think are attributable to trauma and a bad memory.
So, say what you will about what I think happened... but at least it's based on something. It's based on the person most intimately involved in all the events that night, start to finish, and what he says happened. It's augmented by the fact that his account matches physical and eyewitness evidence in several key ways.
Whereas theories about George catching up to Travyon, attempting to detain him, throwing the first punch (and apparently missing), having his firearm already out and waving it around... or using some sort of accomplice to flush his "quarry" from the south back to his position... or lying to dispatch before he was in any legal peril about where he was and where Trayvon was... all of these theories are not only silly, they are based on nothing whatsoever. They are founded on pure imagination and desire, and nothing more.
So do I think George followed Trayvon? Yea. Do I think he "ran after" Trayvon? No. Even if it could be demonstrated to me that he did "run after" Trayvon, I don't think there's evidence that this lasted more than a few seconds, or happened again after he said "okay" and I don't think there's evidence Trayvon could have known George did so.
ETA: I think the fact that he didn't see Trayvon when he got to the "T" junction is a strong indication he didn't run there.