It has always been my understanding, my goal to run a negative split. If that is not possible, well then at least one should run an even split, right?
Early on, I recorded splits in my calendar for every run. This was something I practiced daily. But, how often do runners succeed in this quest? Or, maybe there is evidence the start-fast/crash-and-burn system works just fine?
Everyone Slows Down.
An analysis of the 1995 and 1997 100-km IAU World Challenge race run over a flat 10-km loop course in the Netherlands (Lambert, Dugas et al. 2001), showed the fastest group of runners in both races maintained higher speeds for longer than did the slower groups. The fastest, or best runners had superior fatigue resistance….but both groups slowed progressively.
The study showed that faster runners completed the race while still running at about 90% of their initial pace. Slower runners finished at about 70% of their initial pace. Still, both groups slowed in the second half.
A 2005 informal online poll of marathon runners showed that 73% of runners who ran slower in the second half had still managed to record a PR.
It had been awhile since I had uploaded the data from my runs, so I was a little curious about the splits from the race I ran a few weeks ago.
The first mile came in around marathon pace and by mile 2, I was running at my typical half marathon race pace. I held to this pace pretty tightly – in between the hills.
Total elevation gain for this course was 916 feet with the toughest hill between miles 10 and 11. My pace showed the full effect. I finished strong with each of the last 2 miles run at my fastest average pace of the race.
Even still, my second half was 4 minutes slower than the first half – I did not achieve a negative, or even split.
Start Slow, Finish Strong.
Still, starting out too fast – or slowing down too much – may be more hazardous than you realize.
In March, Runner’s World reported a new Spanish study that shows marathon runners who slow down the most during the race have more muscle damage. The researchers divided finishers into two groups: those who slowed less than 15% from their start pace (22 of the 40), and those who slowed more than 15% from their start pace (18 of the 40). Further tests revealed the second group had more muscle damage than the runners who slowed less than 15%.
It is important not to start out too fast, whether you aim for a negative split or not. If you feel yourself gasping for air, coughing or ready to puke anywhere in the first 2/3 of the race, you’ve probably gone out too fast. You will deplete your glycogen stores and come to a complete and miserable halt long before the finish.
Stop and re-group as quickly as you can no matter how far along you are in the race. You should let your pace advance naturally, evenly. Race day adrenaline and your training will pair up to innately make this pace a fast race-pace instead of your typical training-pace.
So, save the sprint for breaking the tape at the finish line!
Yes, I vote for Start Slow, Finish STRONG.