By David Monti
April 22, 2011
(c) 2011 Race Results Weekly, all rights reserved

(22-Apr) - Geoffrey Mutai's time at last Monday's Boston Marathon was indeed fast, but according to an analysis released today by the independent Association of Road Racing Statisticians (ARRS) his mark should not be viewed as excessively aided.

Writing in this week's "Analytical Distance Runner," the official ARRS publication, chief analyst Ken Young wrote: "It should also be noted that Geoffrey Mutai (KEN) who ran 2:03:02 (in Boston), was ranked #2 on the ARRS competitive rankings and he had been ranked #1 for four weeks earlier in the year.  When Haile Gebrselassie (ETH) set the current world record of 2:03:58.2, he was ranked #10 in the world.  Hence, it is not surprising that Mutai could be capable of significantly bettering the world record.  Too bad that he ran this on a course that is not eligible for records."

According to the Young's Race Time Bias (RTB) calculation, a measure of how fast athletes run based on their previous performances over all distances, the times at Boston were 1:37 fast for the men and 1:42 seconds fast for the women.  That worked out to 2.29 seconds per kilometer for the men and 2.41 seconds per kilometer for the women.  Both figures are well within the 5 seconds per kilometer value the ARRS uses to disqualify performances as excessively aided.

"The net drop is worth about 3 sec/km," Young continued.  "The observed times were roughly 2.4 sec/km faster than expected for the 43 elite runners making up the time comparisons.  Hence, one could conclude that the wind aid was sufficient to balance out the effect of the hills (such as they are)."

Young also pointed out that there were years at Boston where athletes ran much faster per kilometer than this year, based on what would be expected.  The fastest year for men was 1981 when times were fast by 3.8 seconds per kilometer (2:40 total), and 1988 and 1991 for the women, where times were 4.2 seconds per kilometer (2:57 total) fast.

Interestingly, Young points out that the RTB for Boston over all years for which the ARRS has kept data averages out to +0.3 seconds per kilometer, essentially the same as a flat course.  That would seem to indicate that over a long span of time the effects of the weather have canceled out (favorable and unfavorable), and the up and down nature of the course generally produces honest times, even if the course falls by 3.23 meters per kilometer, more than three times the amount allowed for setting world records.

The male and female athletes who ran the fastest based on what was expected were Ecuador's Franklin Tenorio, whose 2:17:56 was 8:51 fast, and Colombia's Yolanda Caballero, whose 2:26:17 was 11:01 fast.

"These RTB values for Boston are well within the range for statistically valid performances and marks from this race are included in the ARRS rankings," Young concluded.


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