DENVER (CBS4) – With the nice weather runners are hitting the trails and roads to get healthy and log mileage. Many are taking their smartphones with them, but not to make phone calls.

Some athletes say running smartphone apps are cheaper than a personal trainer and just as effective.

“Every now and then the zombies chase you and you have to outrun the zombies,” Paul Majors said.

Majors says on most days he is able to outrun the pursuing creatures.

“If you go too slow the zombies catch you,” he said.

Lest you think Majors is somewhat delusional, he’s actually talking about a running app called Zombies Run! that is helping him train. The app provides running support but also tells stories along the way.

“It’s sort of like a video game, but as you run along this story unfolds and there are all these different storylines.”

The storyline throws in zombies to chase the user into running faster.

“I use Strava, and it tracks your miles with GPS and it has training programs too,” Jason Sour said.

Sour is training for the Colfax Half Marathon and says having technical support keeps him honest about the speed and distance of his runs.

“If I wasn’t tracking it would be hard to know my progress,” Sour said.

Anita and her running buddy say they motivate each other but rely on MapMyRun to keep them heading in the right direction.

“It makes sure I keep my pace up and it gives you your splits, so it kind of gives you a goal and it will map out the run that you did,” Anita said.

Most of the training apps are free or cost just a couple of dollars. There are also apps for cyclists.

LINKS: MapMyRun  |  Zombies Run!  |  Strava