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Runners who complete the Christie Clinic Illinois Marathon next April can be certain they’ve raced a full 26.2 miles. And any runner who might set a record in one of the races will know their accomplishment will be officially recognized.

The race course was recently recertified by marathon Co-Director Mike Lindemann and Doug Thurston, race director of the Big Sur International Marathon, who is certified by the International Association of Athletics Federations to measure race courses.

“It’s one of those things that runners don’t think about how it happens or who makes it happen. If the course is set up right, they shouldn’t have to think about it,” said Thurston, who has been certifying race courses for 25 years. “But plenty of courses are not measured or set up right, and runners know it. When it works right, it’s invisible. When it works wrong, it’s very visible. But it’s an important part of the runner experience. Runners expect an accurate course.”

The certification process is governed by USA Track and Field, which requires courses to be recertified every 10 years. Course certification ensures race participants that the courses are accurate, allows records set on the course to be recognized and allows the marathon to serve as a qualifier for the Boston Marathon.

Anyone can measure a course by following the USATF procedures and using a specific piece of equipment called a Jones Counter. It is a device that attaches to the wheel of a bicycle and displays “clicks” or “counts” based on the number of wheel rotations.

The course measurement requires a lot of math. Before the course is measured, the cyclists must ride a calibration course four times. Lindemann and Thurston laid out a 1,000-foot course along a flat, straight stretch of First Street, which they each rode twice to determine how many clicks on the Jones Counter it took to ride that distance. They averaged that number for each of their counters (17,822 clicks per mile for Lindemann’s counter) and used it to extrapolate the number of clicks per mile.

A “short course prevention factor” of 0.1% is added for each mile to ensure the measurement does not come up short of the race distance. That means about 5.28 feet per mile is added to the race distance, or about 138 feet for the whole course.

Courses must be measured twice, or once each by two measurers. Lindemann and Thurston spent 10 or 11 hours on Aug. 3 measuring the marathon and half-marathon courses, and another few hours on Aug. 4 measuring the 5K course. The 10K course was not remeasured due to construction along the route. Lindemann will remeasure it in the spring.

Because the finish line on the 50-yard line of Memorial Stadium will not move, the two measured the course backward from there.

Along the course, Lindemann and Thurston stopped when their counters indicated they reached each mile. They marked the course and made notes of the location, indicating its distance from a permanent marker such as an intersection, streetlight or fire hydrant. For example, mile 18 is described as on Crescent Street and its distance from Jefferson Middle School. They also recorded the locations where timing mats will appear on the course, such as at the 10K mark. The two averaged about 4 miles per hour while measuring.

When the course is measured, those measuring it must take the shortest possible path for runners — for example, as close to the curb as possible on right turns; on a diagonal tangent if runners must cross from one side of a street to another; and straight down the middle of a curving road.

The new course markings are quite close to the old ones, and the start line has been moved back about 50 feet, due to subtle changes along the course caused by construction, Lindemann said.

Many runners use GPS watches and some will question race directors about a course being too long based on what their watches show. Thurston said commercial GPS watches are 99% accurate.

“That means they are 1% inaccurate. That may not sound like much, but that’s 52 feet every mile,” he said. “In a 10-mile race, that’s over 500 feet that’s accumulated.”

Also, he said, “runners are not always running the shortest possible route because of crowding on the course, or maybe they had to dodge people at an aid station or maybe they had to use a porta potty.”

Jodi Heckel, a writer for the University of Illinois News Bureau, is a runner and triathlete. Her email is jheckel@news-gazette.com, and you can follow her on twitter (@jodiheckel).

Jodi Heckel, a writer for the University of Illinois News Bureau, is a runner and triathlete. Her email is jheckel@news-gazette.com, and you can follow her on twitter (@jodiheckel).