I'm uneducated in the current official measuring rules and how they relate to the real world. Please help me understand course measuring.
What is the length of a marathon with the SCPF added? Does adding 1% makes it about 26.46 miles? Do they add about 17.6 yards to each mile segment when locating the split points so there is 1777.6 yards between mile splits?
thanks
SCPF is 0.1% (not 1%), so about 42.195 meters for a marathon.
It's 0.1%.
The short course prevention factor adds 1 meter for every km which equates to 10m for 10km & 42.195 meter for the marathon.
When a course is measured, the measurer will incorporate the short course prevention factor into all splits.
For example:
Courses are measured using a direct drive mechanical device mounted on the axle called the Jones Counter. It counts approximately 11 counts per meter depending on tire size.
Before and after each measurement,the counter is calibrated against a straight line distance of at least 300 meters. This calibration course is measured with a steel tape taking into account the expansion of the tape due to temperature.
The measurer rides several times over the calibration course (minimum of 4). Knowing the average number of counts for the calibration course, the measurer can calculate the number of counts per mile. The measurer will then add the short course prevention factor for each of those miles. If the calculations determine that a mile = 18100 counts, approximately 18 counts will be added = 18118 counts per mile.
A post calibration is performed after the measurement and adjustments are made if needed.
an additional quarter mile changed his name and rewrote:
I'm uneducated in the current official measuring rules and how they relate to the real world. Please help me understand course measuring.
Do they add 1/26th of the aprox 42m to each mile segment when locating the split points?
thanks
Thank you all for the correction to 0.01%
Not 0.01%, 0.1%.
Courses are measured three times using above methods and the average measurement must be at least 42.195 meters long, even if all three individual measurements are not. Really good course measurers can get all three measurements precisely within 6-7 meters so that 42 meter requirement is pretty safe.
D Katz wrote:
The short course prevention factor adds 1 meter for every km which equates to 10m for 10km & 42.195 meter for the marathon.
When a course is measured, the measurer will incorporate the short course prevention factor into all splits.
For example:
Courses are measured using a direct drive mechanical device mounted on the axle called the Jones Counter. It counts approximately 11 counts per meter depending on tire size.
Before and after each measurement,the counter is calibrated against a straight line distance of at least 300 meters. This calibration course is measured with a steel tape taking into account the expansion of the tape due to temperature.
The measurer rides several times over the calibration course (minimum of 4). Knowing the average number of counts for the calibration course, the measurer can calculate the number of counts per mile. The measurer will then add the short course prevention factor for each of those miles. If the calculations determine that a mile = 18100 counts, approximately 18 counts will be added = 18118 counts per mile.
A post calibration is performed after the measurement and adjustments are made if needed.
Thank you for that full and complete answer.
No problem
fyi
USATF requires two measurements for a course to be certified in the US not 3). Internationally, only one measurement is required but most of the times there are at least two.
If a record (USA or World)is broken, a verification measurement by an IAAF "A" grade measurer is required unless two IAAF "A" (or one "A" & one "B") perform the original measurement.