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Posted: January 8, 2005
Athletics: Running Even Splits In The Marathon
Are You Using the Same Strategy as the Pros?
By: Al Morris, Ph.D.,FACSM
If you want to run a PR time in the marathon, it's very important to run equal halves. In fact, over the years many athletes, elite and non-elite, have demonstrated that the ideal scenario is to run the first half of the race slightly slower than the last half. When you start slowly you allow your body to adjust to the pace and the exertion, which leaves you with enough reserves to run the second half as quickly as the first, or EVEN FASTER!
Negative Splits Make A Positive Difference
The top men and women in the 2002 Boston Marathon admirably demonstrated the advantages of running negative splits (the second half run faster than the first). The lead men ran a very strategic race, which resulted in a half-marathon split time of 1:05:21. At the half-way point there was a lead pack of approximately two dozen runners that included the defending champion, Lee Bong-Ju of Seoul, Korea, Silvio Guerra from Ecuador, and Rogers Rop from Kenya, a relative youngster at the age of 26, who was running only his second marathon. Rop ran the second half in 1:03:41, and won the race with a time of 2:09:02. Even on the difficult point-to-point course, with major hills in the second half, Rop was able to run negative splits, which resulted in a win. The second place finisher, Kenyan Christopher Cheboiboch (another youngster, 25), also ran 1:05:21 for the first half and came back with a 1:03:44 for the second.
The defending women's champion, Catherine Ndereba, returned in 2002. Besides the world record holder Kenyan, there were strong runners from China, Ethiopia, and Japan. Two Kenyans, a Chinese runner and an Ethiopian runner passed the halfway point in 1:10:43. Shortly after the Newton hills, one of the Kenyan athletes, Margaret Okayo, pulled ahead of Ndereba to win in 2:20:43, breaking the previous women's record by just over a minute. Okayo ran the second half in 1:10, nearly a minute faster than the first. Ndereba, who finished second, also ran the second half faster in 1:10:29.
Pacing Produces PP's And World Records!
Ethiopia's Belayneh Dinsamo held the world marathon record of 2:06:50 for ten long years. He set the record by running nearly exact splits of 4:50 per mile for the entire 26 miles. His second half split time was only ten seconds slower than the first half. Then in 1998 Ronaldo da Costa from Brazil ran the first half of the Berlin Marathon in 1:04:42, and followed that with an almost unbelievable 1:01:23, for a new world record of 2:06:05. He ran arguably the fastest second half marathon in history. No male runner has duplicated the 3:19 differential since. The amazing Khalid Khannouchi broke the 1998 record in 1999 by running a 2:05:42 (1:03:07 first half, followed by a 1:02:35 second.) Then in 2002 he broke his own record in London with a 2:05:38, running nearly perfectly even splits for both halves.
Like the men, the women's marathon world record had stood for many years (14) before it was broken in 1999 when Kenyan Telga Loroupe ran 2:20:43, beating Norwegian Ingrid Kristensen's record by nearly a minute. Loroupe ran the second half of her record-breaking race just a minute slower than the first. 2001 saw the women's record broken twice in one week. Japanese champion Naoko Takahashi took the women's record under 2:20 for the first time in history in Berlin, running splits of 1:09:48 and 1:09:58 for a sensational 2:19:46. Only six days later, Catherine Ndereba lowered that time to 2:18:47, running split times of 1:10:15 and 1:08:32 in Chicago. Then in the 2002 London Marathon, first-time marathoner Paula Radcliffe from Great Britain ran a remarkable 2:18:56, good enough for the win, the fastest first time marathon, and the second fastest marathon finish ever by a woman. She also achieved another milestone: a second half split nearly equal to Dinsamo's record-breaking time. Radcliffe ran the second half in 1:08, nearly three minutes faster than the first.
The Physiology Involved In Running Negative Splits
Marathon runners use fats and carbohydrates as fuel; fats are burned only aerobically, carbohydrates are burned both aerobically and anaerobically. Carbohydrates are the fuel of choice, however they will last only about 18-20 miles in even the most gifted runners who start the race fully loaded. This is why you must run slowly enough initially to stay "aerobic", so you'll use a little bit of fat as fuel. By burning this fat on the flame of carbohydrate, you spare some carbohydrate for use later in the race. But if the you get excited and go out at a pace that can't be sustained, you will become anaerobic and use too much carbohydrate (stored muscle glycogen), which will cause you to reduce your pace and fall behind.
According to distance running researcher Dr. Dave Costill, aside from the limits imposed on runners by heredity and the ability to train hard, diet is the single most important factor the athlete can manipulate if he or she is going to succeed at the marathon distance. Pre-race diets high in carbohydrates allow you to store muscle glycogen and to use the stored glycogen late in the marathon. If you haven't consistently eaten a high carbohydrate diet (65% or even more in the days just prior to the event) you will not be fully tanked up with stored glycogen reserves. The marathon is raced at about 80-95% or more of maximum oxygen capacity (VO2max). At this intensity the predominant fuel is carbohydrate, which must be stored if you want to maintain a steady pace for the entire marathon.
Also, most distance runners have a predominance of slow twitch fibers in their lower legs. These fibers prefer to function aerobically, and they use both fats and carbohydrates as fuel. However, all runners have some larger muscle fibers in the same muscles called fast twitch fibers that, although they prefer to function anaerobically, also at times use aerobic fuels from fats and muscle glycogen. When the runners in the lead pack surge, they use some stored muscle glycogen in their fast twitch fibers as the pace increases. Surges don't last long, since runners often are running above their lactate threshold, which promotes faster depletion of glycogen reserves and a corresponding earlier collapse or slowdown.
Truly elite runners are capable of running at a very high percentage (approximately 80-95%) of their VO2max for the entire marathon distance. This unique ability is partly genetically endowed, but to a great extent it's developed over time through consistent training and a high carbohydrate diet. Elite athletes also develop an extraordinary sense of pacing by repeatedly practicing pacing during training and shorter races (from 10Ks to the half-marathon). The sense of pace pays off during the marathon when they can sense any slight pacing disruption and react to it. They teach their bodies how to run at such a fast, yet aerobic effort by specific training (such as practicing surges and longer sustained intervals), frequent racing at shorter distances, and eating significant amounts of carbohydrates after training and racing to replenish muscle glycogen.
Mimic The Pros And Reap The Benefits
1. Practice running at marathon goal pace during some of your training runs.
Al Morris, Ph.D., FACSM, ran his best race off even pacing in 1978 with a 2:44. He ran several others, but came nowhere near his best time, so he retired with 36 marathons under his belt.
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