The new trend in sprints and marathons seems to be the inclusion of the walking dead, which is a strange decision. There's a Zombie 5k in Golden Gate Park this weekend and a zombie run of unspecified length leaving from Union Square a week later. Overall, this is a new move for the undead too, exercising with such vigor, although they have been known to dance in groups for decades.
The idea of running zombies didn't really exist until 2002's 28 Days Later, and those were people infected with a rage virus, not true undead at all. Two years later, we got the remake of Dawn of the Dead, which featured more agile corpses than were traditional at the time, and there seems to have been no stopping the spread of "runners" ever since. Zombieland in 2009 gave as its rule number one that cardiac exercises were necessary in combating the once walking dead.
We've reached the point as a culture where animated corpses have become exercise aids. The Zombies, Run! app automates the process of running to avoid getting eaten, harnessing our fears to make us stronger. I guess this is a thing now.