How long was Portland Course Anyway?

Well, if you ask ME it was 26.47.

I got an email from the Portland Marathon Association yesterday telling us how successful Portland was this year. WHO are they trying to convince? Me? Because IMO  it was a flop! Ok, that is a little dramatic but I am holding a serious grudge against Mother Nature for that day and am suffering from PTSD as a result of the conditions and the looooooooooooooong course. Ok, anywho…I got this email and at the very end of the long email I found this small blurb and wanted to share it with you all. It is good info to know not only about Portland but about how they actually certify and measure courses. In turn it tells YOU and ME how to run a course so that we only run 26.2, or 13.1 or whatever the actual distance is supposed to be. And I know this to work because in the Mercer Island half back in March I hit 13.13 on my Garmin at the end of that race, pretty darn close to 13.1 don’t you think? And I ran the course just as they suggest in this blurb. So read and learn my fellow runners, read and learn:

Portland Marathon course—trust us, it's certified in every way.

By Les Smith, Event director; Richard Busby, Course Technical Director; Lee Barrett, USATF/RRTC National Certifier for Oregon

We have received inquiries from several participants in the Portland Marathon held on October 10, 2010. To sum them up they all asked: “Why was the distance measured by my GPS watch longer than the official Marathon distance of 26.22 miles?” “Is the course wrong?” Experience has shown that the comparison of a marathon course measured by the approved method with the read-out by on a GPS watch worn by a runner on race day reveals the GPS readings are slightly longer than the certified distance. Because of such long course concerns, we recently measured the marathon course following a route more like that a runner would take, than cutting each corner as required for certification.

We used a Jones counter, the standard instrument used to certify courses, and a Garmin Forerunner 305 GPS watch. The Jones counter had the route we took being 26.27 miles long and the Garmin recorded 26.35 miles. The Portland Marathon was measured using the procedure required by USA Track and Field, (USTF) Road Running Technical Committee, the governing body for US road running. The course was also certified by USTF/RRTC and IAAF/AIMS. USTF and AIMS have strict methodology for measuring courses for certification.

The standard measurement device used is a Jones counter which is attached to the front wheel of a standard bicycle and must be calibrated before and after the measurement ride. A Jones counter typically shows around 15,300 counts per mile, or about one count every three inches. Our course was measured in this fashion by two very experienced and certified course measurers.

The measurement process requires measuring the shortest-possible distance a runner can run on race day. To ensure this, the measuring bicycle is required to ride 30 cm from the curb at each corner. The measurer must also ride the straightest line through curves and turns. The goal of this is to make sure that on race day all participants run at least the full distance of the marathon or other certified distance, as the case may be.

The former Chair of the RRTC has estimated that for the Portland Marathon course, with something like 36 turns, a runner going 1 meter wider than the shortest possible route on each turn would run an extra 53.6 meters. To permit our measurement team to follow this process as closely as possible, the measurement of the Portland Marathon course was done early on a weekend day to minimize traffic allowing us to measure the shortest route possible. On race day with over 10,000 other participants, running that “shortest distance” course would prove to be extremely difficult due to, among other things, runner traffic and the location of water stations.

The course certification process also requires the inclusion of a “short course prevention factor, “The measurer must add 1 meter of additional length to the course for every 1,000 meters of course length. Thus a 10 km certified course is measured to be 10,010 meters long. And, a certified marathon course has an additional 42 meters added to its length.

It is well recognized that GPS devices available to the general public are about 1% percent inaccurate when compared to the mechanical measurement of a known distance using the bicycle counter mentioned above.

Many factors can affect the accuracy of a GPS watch. Tall buildings along the route, rain, trees covering the course, elevation changes and the number of satellite signals received all affect the accuracy of the GPS measurement.

When the inability of the runner to run the shortest course on race day and the small inaccuracy of the GPS watch are combined, GPS readings of 26.50 miles for a certified 26.22-mile marathon are not unusual. These factors do not mean that the course is not accurate. All it means is that the GPS actually measured the distance that you, the runner, covered on race day. You did a great job because you can know for sure that you ran the full marathon distance! We know that this year was particularly challenging due to the weather, so your challenge was even more difficult to accomplish, but you completed it. Congratulations!

Ok, now that THAT has been cleared up I am off to run 5 miles of trails, well firmly packed dirt, around The Hubs new work place. Should be fun. Hopefully.