If you’ve read my novel “Ultra,” you know all about pacers. Pacers are the lind-hearted lunatics who volunteer to “pace” runners for the final 20 or 30 miles of an ultra-marathon.

Being a pacer is a tough job. First, they have to run twenty or thirty miles – on forest trails, in the middle of the night.

They also need to open to abuse. Runners can get mean after 70+ miles.

Most of all, a good pacer needs to know when to push, and when to back off. On that front, here’s 90 seconds of solid advice.