Previous trail runners have commented on the difficulty of the terrain:

In fact, there are more trail runners here than we thought possible.

Some trail runners attach lightweight crampons to the bottom of their shoes to aid with traction in the snow and on ice.

Some trail runners use ultra light hiking poles (which are often not allowed during competition) to increase speed and stability.

There are 40 million trail runners nationwide as of 2005, according to the Outdoor Industry Foundation, up 22.1 percent from 1998.

I'm considering hiking with trail runners instead of boots.

Get a pair of good trail runners.

Floyd made a throw to third base that allowed the trail runner to sneak into second.

For an experienced trail runner, overall it is an easy trail.

There are more advanced weeks for trail runners, adventure racers and triathletes.