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Formula for a Certified Course
E=MCH^2: The Formula for a Certified Marine Corps Historic Half Marathon Course
On May 20 in Fredericksburg, VA approximately 8,000 runners will run a certified 13.1 miles at the Marine Corps Historic Half marathon. Some participants will have consulted a course map prior to the race; others may use GPS-enabled watches to chart their run; and a great many will simply follow the crowd and observe the mile markers along the way to gauge the race distance. But how can runners be sure they are covering the full advertised 13.1 mileage?
Enter Vic Culp, executive director of Race Timing Unlimited located in Fredericksburg, VA. Culp plays a very important role in the Historic Half: He is the course measurer. With experience certifying over 100 road race courses, Culp conducts a thorough certification process taking place in the months prior to the race with the support of the MCM Operations team. Read on for a fascinating look into how the Marine Corps Historic Half marathon course takes shape:
MCM: How is USA Track and Field (USATF) involved in the course certification process?
Culp: USATF developed the guidelines and manuals. Once I finish measuring a course, I send a hand-drawn map and records of the measurement counts to the Virginia USATF certifier. He reviews my measurement counts and calculations for errors. If all is clean, he then assigns a course number and files the paperwork with USATF, where the map is posted on the usatf.org website.
MCM: What qualifications are necessary to become a race course certifier?
Culp: Anybody can become a course measurer. USATF has an 80-page booklet that explains the process. If one can follow the instructions and has the drive to get up early in the morning on weekends and ride a bike in a straight line in traffic, they can measure a course. It helps to be strong with math, a strong cyclist and have good far vision.
MCM: How long have you been certifying?
Culp: 17 years. The first course I measured was the River Run 5k in Fredericksburg in March 1995.
MCM: What instruments do you use to measure distances?
Culp: To start the measurement process, we use a 100-foot steel tape. At 69 degrees Fahrenheit and 10 pounds of pressure, a 100-foot steel tape is 100 percent accurate. Using physics, the actual length of a 100-foot steel tape can be calculated when the temperature is not 69 degrees Fahrenheit. Steel expands at a higher temperature. Laying the tape end to end, we have measured a 1/5 mile calibration course on Kenmore Ave. in Fredericksburg. To mark each end of the calibration course, we have driven a PK nail into the pavement.
When doing a course measurement, I use my bicycle with a Jones counter on the front wheel. For every revolution of the front wheel, the Jones counter records exactly 20 clicks, as the device is 100 percent mechanical. Riding the bicycle on my Kenmore Ave. calibration course, I can determine the number of clicks per mile and by multiplying by five the number of clicks per 1/5 mile. Depending on air temperature and the amount of air in my front tire, the clicks per mile will be between 14,990 and 15,030 or about four inches per click.
After calibrating, I ride the course twice and if the two measurements are within .08 percent clicks, the measurements are considered valid. I then ride the calibration course again to make sure there have been no material differences in the clicks-per-mile. With these procedures, the measurement is accurate within 1/10 of 1 percent or 16 feet for a 5K.
MCM: Often runners comment on discrepancies between Garmin distances and the certified race distances. How do you explain this?
Culp: There are a couple of reasons where the Garmin measures a course longer than the advertised distance. When measuring, we are required to ride the shortest possible route that a runner can take, which includes being one foot from the tangent of any turn and straight line diagonals between opposing turns. In the actual race, some runners do not take these shortest routes because of crowded road conditions or inattention.
GPS devices are accurate to between one to 10 meters. The GPS device takes a reading every one to five seconds. When doing a distance calculation, the GPS will calculate the distance between each reading and add this to the total distance covered. So, when running down a straight road when a reading is done, the GPS device might record a point that is one to 10 meters from where one is actually at, which might be to one’s left or right. The next reading might be to one’s left or right. This creates a series of points, connected with a zigzag line, which would indicate a running distance longer than one actually covered.
MCM: How long does it take to certify a half marathon course?
Culp: The process normally takes me about one hour-per-kilometer. So a half marathon takes about 21 hours.
MCM: As someone with intimate knowledge of the Marine Corps Historic Half course, what are your thoughts on this race?
Culp: The course and race are challenging. Because of the distance of the race, to keep the entire race within the city, the hills cannot be avoided. Central Park is one of the higher elevations in the city at about 250 feet as opposed to about 30 feet on Caroline Street. To start and finish in Central Park, the downhill at the start and uphill at the finish cannot be avoided. The worst hill at the finish is not Hospital Hill, but rather, the long uphill in mile 12 on Cowan Boulevard. This is one race where a runner needs to take advantage of the downhill in the beginning and try not to run negative splits.