Don’t run so fast in the beginning- is negative-split the deal?

How do you plan and execute a longer endurance swimrun race like the Rockman Swimrun? Do you go hard in the beginning to set up a comfortable lead (positive split) or do you start of relatively moderat and increase during the race (negative split)? Check out (below) what Coach Fredrik Sillen has to say on this topic.

/The WoS Team

Here you’ve trained and trained for the big running goal of the year. You’ve cut down on the level of training the week before and feel strong and refreshed. You’ve recharged with energy and fluid, and the butterflies in the stomach has started the production of a number of different body-types-drugs such as adrenaline. And at the sound of the starting gun, all racers rush-off like a runaway herd of wildebeest. With this in mind, it’s not surprising that many runners run a little faster than they should in the beginning of the race.

You can of course run as fast as you want in the beginning. But one should know that virtually all world records in long-distance running is beaten when the first and second half is run equally fast, or when the second half faster than the first, a so-called ‘negative split’. In general, for the elite there’s not much difference between the first and second half, where the second usually is slightly faster. When Dennis Kimetto beat the men’s world record in Berlin in 2014 (2:02:57), the second half was only 37 seconds faster than the first. In Berlin this weekend, Kenenisa Bekele finished with the second fastest marathon time in history, only six seconds from a new record (2:03:03). In this race however the first half was 42 seconds faster than the last half of 21 km.

When Paula Radcliffe set her phenomenal record of 2:15:25 in London in 2003, the first half was covered in 68.02 minutes, compared to the second in 67.23 minutes, i.e. 39 seconds faster.

But what does the average jogger do? Well, not like the elite, and I’m not talking about the joggers running at a slower paced than the elite, but most run the first half of a marathon significantly faster than the other half. It feels good in the beginning and when you look at the clock, it’s so easy to think “well it goes a little fast now, but it’s good if I’m a bit ahead of schedule for later in the race when I get tired”.

This way of thinking is bad in most cases. Now, the people behind the Strava app has gone through the numbers of those who have used the app in different marathons in the United States. In the picture below you see how it looks (picture from Competitor Running). Dark grey mean that the first half was faster than the second, light grey that both halves were about equally fast (how exactly is not clarified however) and the orange coloured ones are those who ran with negative split. In the Boston Marathon, the bar on the far right, only 1.9 percent managed to be faster in the end. The race where most managed to get a negative split, the Chicago marathon, the leftmost bar, however only as low as 8.5 percent.

How many runner using Strava during their races, included in this review is not clear? And as I said, what counts as “equally fast” is also not clear. But in my experience and those I train, these numbers are not that far from reality. I often recommend runners that have a watch that measures speed, to wear it during a race. I know that some people always want to keep track of heart rate and speed while competing with others, where some prefer to go on their gut feeling. But also you “emotional runners” out there (including myself), can benefit greatly by keeping track of the initial speed at the start of a race. I remember once at a duathlon-competition, when after a few minutes looking at the watch, thinking to myself that I was really good at not going so fast in the beginning, only to realize that my 3.15 min/km speed simply wasn’t reasonable for a runner like me.

Summary: Read the title again! And practice to run the second half of your runes faster than the first.

/This article is a summary translated from its Swedish original (found here), written by the legendary Swedish specialist running coach, Fredrik Zillén.

Fredrik, the Founder of Spring Snabbare (Run Faster), has coached several ÖtillÖ medalists with their running technique.