fast zombies???

so, i never got the idea that zombies are/could be fast. sure, it makes sense that zombies could be fast but it feels more realistic for them to be slow. i do think it depends on how you think about the creation of zombies and how they work. 

If they've been created the same way that 28 days later (a viral infection stemming from an already existing brain-disease or rage/instinct), then it would make sense that zombies could be fast. If they're not technically dead and more sick/infected then they would probably be fast. Often times the only thing holding people back is their through process about what they're trying to do. So, if the critical thinking parts of the brain gets shut down and the person is running on pure survival instinct, it would make sense for these zombies to be fast. 

However, if the zombies are more like the Dawn of The Dead zombies (killed by the zombie infection, then self-revived kinda also by the virus), then the fast zombies wouldn't work. If the body and brain have already been shut down, the muscles and joints could very much have started to break down and there would be no way that these zombies could be fast. though, if they aren't dead for long, the muscles could have just run on pure instinct and be faster than they were in life.

But, if the zombies are like the Night of The Living Dead (idk how that started actually but there were people brought back from graves and shit i think) then there would be no way that the zombies would be fast. i think i'm thinking about this too much, i have nothing else to do tbh.

what do you guys think? would fast zombies make sense or nah? do you even like the idea of fast zombies or do you prefer the more traditional idea of zombies being slow?