It’s funny how we accept conventional wisdom as just that: wisdom. Ask any runner what is the best way to pace a marathon and they will almost certainly say run it at an even pace or with a negative split (negative split is 2nd half faster than 1st).
But, why is this? Simple, it’s because this is the advice that has been handed down over the years from respected coaches, published in books and magazines, bandied about in forums, and recommended by experienced runners in running clubs all over the world. But where did they get their information from? Do we know? Maybe we should check it out, because if we take a look at how the elite runners perform in the marathon we might get a surprise.
Below are some figures from the top one hundred finishers at some of the fastest marathon courses in the world. These races attract the very best runners on the planet. Specifically, the figures give the percentage of those same top 100 runners who ran a negative split.
| Race | 1st place time | 100th place time | Top 100 with negative split |
|---|---|---|---|
| Fukuoka 2011 |
2:07:36 | 2:31:48 | 1% |
| Berlin 2011 |
2:03:38 | 2:33:32 | 14% |
| Chicago 2012 |
2:05:37 | 2:33:08 | 8% |
| London 2012 |
2:04:44 | 2:36:28 | 6% |
Clearly, running a negative-split marathon is a rare thing.
Actually, it shouldn’t surprise us at all, running is extremely hard and uncomfortable during the latter part of a marathon. Although running at the intensity of marathon pace is well within us, as the miles pass by the discomfort becomes increasingly difficult to overcome. The legs hurt, the feet hurt, in fact the whole body hurts so much that the mental effort required to keep running at our goal pace is very often too much to bear. But it’s not just the mental effort, it is well documented that running a marathon at even pace will result in a gradual increase in heart rate too, i.e. it becomes physically more demanding to maintain a constant pace. The result? We cannot maintain our pace, our heads drop, our target time vanishes into the distance and by that time it’s too late, we have entered the marathon runner’s worst scenario: a negative mental state.
Running at a constant pace for 26.2 miles is a huge challenge, so why are we setting ourselves up for failure during the race by attempting to do something that even the very best in the world rarely manage? The runner’s mental state is an absolutely huge determinant of their performance, and of course, it increases in importance according to the distance of the race. We should be running a strategy that preserves a healthy mental state for as long as possible and not one that destroys it.
But, why we are advised to target a negative split? Most of the reasons are psychological: if you run a negative split you will be passing other runners and feeling good about speeding up. Yes, that’s great — in theory. The problem is that it’s just too far out of reach to make it anything other than a fool’s goal. Anyone who has run a marathon and found themselves slowing down during the second half will know what a demoralising experience it can be. The reason it’s demoralising is because our race stops going according to plan. Slowing down has all those negative connotations: I am more tired than I should be, it’s hurting too much, I can’t keep going at this speed, everyone around me is handling this better than me.
But, wait a minute, what happens if we actually plan and expect to slow down as the miles pass by (because this is what happens)? All those negative thoughts cease to exist; we stay on track, content that everything is going according to our plan and we are more able to focus on our race rather than our disappointment for the way things are going.
It’s a bold move to alter the way we think about ideas that seem set in stone. Nevertheless, without doubt, the data indicates that we should question why we chase such a challenging target as the negative marathon split. The chances of failure are extremely high and the consequences of realising that failure during the race can kill any possibility we had of running a satisfactory race. It could be far better to adjust our own times, either our goal finishing time to allow for some slowing down, or our race splits so the early miles are run slightly faster to bring us in on time allowing for that slow down.
If you want to read more about this, the GB ultra runner (and sports scientist), Stuart Mills, has some fascinating insights on endurance running pacing strategy.
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