Negative Splits
"Negative Splits" usually means the second half of the race is faster than the first. This has been promoted by many experienced runners and experts for a long time. Why does it work? The author is not aware of any scientific studies elucidating the reason for running negative splits to be a good strategy for racing. The following is the author's hypothesis:Running involves the coordination of multiple systems of the body (e.g. metabolic system, muscular system, etc.). Every system has a sort of inertia in a broad sense. It takes some time after a race starts for the inertias to fade away. During the initial phase of a race (e.g. the first three miles of a marathon), the cost in terms of energy consumption, accumulation of lactic acid or microscopic muscle damage is higher than later phases at the same pace. The performance of a race is limited by some accumulative factors. For shorter distances such as 10K or shorter that are run above the lactate threshold, the limiting factor is the accumulation of lactic acid. For longer distances such as marathon that are run well below the lactate threshold, the limiting factors are accumulated microscopic muscular damage, energy exhaustion, accumulated imbalance of body fluid electrolytes, or depletion of some elements. Starting slowly and gradually increasing the speed help minimize these accumulative factors in a race.
Here are a few examples of how negative splits worked:
- Ronaldo Da Costa set a new marathon world record with a time of 2:06:05 at Berlin Marathon in 1998. His half way splits: 1:04:42, 1:01:23. The lead pack km splits are as follow (Ronaldo Da Costa took the lead soon after the half way):
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Ronaldo Da Costa took the lead
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(source: IAAF)
Catherine Ndereba smashed the world record by 59 seconds at 2001 Chicago Marathon with a time of 2:18:47. Her half way splits: 1:10:14, 1:08:32.
Her 5K splits:
5-K: 17:41
10-K: 34:09; 17:04
15-K: 50:39; 16:53
20-K: 1:06:45; 16:41
25-K: 1:22:49; 16:34
30-K: 1:39:04; 16:31
35-K: 1:55:21; 16:29
40-K: 2:11:45; 16:28
Ndereba covered the first 10 miles in 54:18 and the second 10 miles in 51:54. That 51:54 split is only 38 seconds slower than the women's world record for 10 miles-- 51:16 at that time.Her half way splits are 1:10:15 and 1:08:32. That second split is just 2 seconds slower than her half-marathon winning time (1:08:30, a course record) in the Philadelphia Distance Run a few weeks before the marathon. She ran her personal best for the half-marathon, 1:07:54, in The Netherlands the March that year.
When Paula Radcliffe smashed the world record at 2002 Chicago Marathon, her
splits were 1:09:05 for the first half and 1:08:13 for the second half.
(source: Runner's
World)
When Deena Castor won the bronze medal of marathon at 2004 Athens Olymics (the first Olympic marathon medal for America since 1984), she ran the second half faster than any other athletes (including the gold and silver medal winners - Mizuki Noguchi and Catherine Ndereba). In an interview, Castor said: "My entire game plan was to run a conservative first 10-K. Coach Vigil and I had talked it over dozens of times, agreeing that it was critical not to overheat early. It didn't bother me to see the others go out faster. At one point, I think I was in 26th place, but I was totally focused on myself. I didn't have any other runners in my mind " (courtesy of Runner's World).
(Originally written on 10/13/2001)
