WHY DON'T MILE MARKERS MATCH UP WITH MY GPS?

I am a 21-year-old female runner, and I have completed two half-marathons and two full marathons. I am a PR-seeker and eventually would like to qualify for the Boston Marathon. One of my biggest problems with achieving a PR during a race has to do with discrepancies between my GPS watch and the race-course measurements.

road race management, advice to runnersDave McGillivrayAugust 31, 2009gps, mile markers, course management, course clocks, course certification, USATF certified course

GPS PHENOMENON

During the past year, I have received a number of emails from runners who have participated in a few races I have directed complaining that the course was "too long."

advice to race directorsDave McGillivrayJuly 1, 2009gps, course certification, USATF certified courseComment

MOVING ROAD CONES