Road Race Stats - Marathons & Other Running Races

Wednesday, June 22, 2005

Grandma's Marathon Split Comparisons

Running a consistent pace throughout a marathon is much easier said than done. I've looked at the first and second half splits of last Saturday's Grandma's Marathon in Duluth Minnesota. Only about 22% of the runners were able to keep their first and second half times within 5 minutes of each other. About 75% ran the second half over 5 minutes slower. Only about 10% of the runners ran the second half faster.

It's interesting to note how similar this is to the Knoxville Marathon. The Grandma's Marathon runners were a tad more consistent. In the Knoxville Marathon only about 20% of the runners were able to keep their first and second half times within 5 minutes of each other (2% fewer than Grandma's). The weather was quite a bit different between these races. For Knoxville, the temperature went from 41°F to 55°F. For Grandma's, the temperature went from about 55°F to 69°F. Even though Knoxville was cooler, there was more temperature variation. This could be why Knoxville had about 1% fewer runners who ran the second half faster.

In looking at the splits, it's interesting to see how consistency varies with finish times. One would expect that the faster runners (who might be more serious and experienced) would have more consistency. For consistency I mean keeping their first and second half times within 5 minutes of each other. That does seem to be the case. Below is a summary of the percentage of runners who had about equal splits (+/-5 minutes) broken down by overall chip finish times.

These are very similar to the Knoxville Marathon results except for runners who finished under 3hr and over 6hr. Knoxville Marathon was much smaller and only had 19 runners in each of those extremes. Grandma's Marathon had 168 under 3hr and 141 over 6hr. So that may explain the difference in percentage and why Grandma's Marathon has a consistent trend showing a higher likelyhood of pace consistency with faster times.

Finish Percent of runners who
Times kept 1st/2nd half splits
within 5 minutes
----------- -----------------------
under 3hr: 67%
3 to 3.5hr: 46%
3.5 to 4hr: 33%
4 to 4.5hr: 19%
4.5 to 5hr: 9%
5 to 5.5hr: 8%
5.5 to 6hr: 3%
over 6hr: 2%
Overall: 22%

Below are the stats in table formats derived from the Grandma's Marathon results page. The halfway times are assumed to be chip times.

Half Split Changes for Under-4hr Runners

Split ChangeMarathon Chip Times
Under 3hr3 to 3.5hr3.5 to 4hr
More than 5m faster5 (3%)15 (2.2%)61 (3.6%)
Less than 5m faster30 (17.9%)78 (11.5%)196 (11.6%)
Less than 5m slower83 (49.4%)236 (34.7%)362 (21.4%)
More than 5m slower50 (29.8%)349 (51.3%)1062 (62.8%)
Unknown 2 (0.3%)11 (0.7%)

Half Split Changes for 4hr-to-5.5hr Runners

Split ChangeMarathon Chip Times
4 to 4.5hr4.5 to 5hr5 to 5.5hr
More than 5m faster45 (2.5%)44 (3.2%)13 (1.8%)
Less than 5m faster92 (5.2%)55 (4%)13 (1.8%)
Less than 5m slower242 (13.7%)74 (5.4%)43 (6%)
More than 5m slower1385 (78.2%)1195 (87%)647 (90.2%)
Unknown7 (0.4%)6 (0.4%)1 (0.1%)

Half Split Changes for Over-5.5hr Runners and Overall

Split ChangeMarathon Chip Times
5.5 to 6hrOver 6hrTotal
More than 5m faster6 (1.8%)2 (1.4%)191 (2.8%)
Less than 5m faster3 (0.9%)2 (1.4%)469 (6.8%)
Less than 5m slower7 (2%)1 (0.7%)1048 (15.2%)
More than 5m slower324 (94.7%)136 (96.5%)5148 (74.8%)
Unknown2 (0.6%) 29 (0.4%)


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