If your familar with the mainstream horror flicks like "Dawn of the Dead"(2004) and "28 Days Later".. saying they running zombies are new, WRONG!
They have existed before in early foreign horror movies that you should definitely watch! there was of course Umberto Lenzi's 1980 Horror/Sci-fi/action shocker "Nightmare City" ( a.k.a. City of the Walking Dead) which featured the first running zombies but these zombies also drove cars, have cruddy faces, and weild weapons including sucking blood like vampires.
Then there was "Lifeforce", "Return of the Living Dead trilogy", 'The Stuff" and "Zombi 3" that also had zombies that ran.
This is like the 5th time you've brought this up. "28 Days Later" isn't "mainstream", it doesn't feature "zombies", and nobody ever claimed that. This whole "running zombies" is such a dead issue...nobody cares.
If you want to argue semantics, the people in "28 Days Later" were still very much alive and not considered "zombies". They were merely infected with "rage" or whatever it was.
"28 Days Later" is an independent U.K. movie that ended up showing in the US about 3 years after it was originally released, and even then, it only made it to 1,400 screens nationwide, compared to what most would consider mainstream, like "Land of the Dead", showing on 2,300 which is more of a mainstream release.