What It Means to Run a Negative Split

runners in race
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The term "negative splitting" refers to running the second half of a race faster than the first half. It is a pacing tactic for running as well as for other sports such as swimming. You can do negative splits for any distance of race, from 5K up through marathons, and use it for training runs as well. It's most commonly used as a racing strategy for long distance races such as a half or full marathon.

For instance, if you're running a marathon and you run the first 13.1 miles in 2:01:46, and then run the second 13.1 miles in 1:59:30, you ran a negative split.

Negative splitting is often called the ideal way to run a long distance race such as a half or full marathon. Many runners do the opposite by going out too fast in the beginning, and then slowing down significantly in the second half of the race. It's a common mistake because you feel rested and strong in the beginning, so it's tempting to go out fast. Runners think that they're "putting time in the bank," but the strategy often backfires, as they burn through their stored energy in the first half and feel fatigued in the final miles.

Achieving a negative split requires a lot of discipline and practice, both in training and the race itself. Most people can't do it in their first marathon. But, generally, if you can hold back and conserve your energy in the first half of the race so that you can run faster in the second half, you'll perform much better overall.

Positives

A more conservative pace at the beginning of the race gives your muscles more time to warm up. Many big races are very crowded in the first few miles, so you may be running a bit slower anyway. Running a negative split also decreases your risk of hitting the wall in the late miles of a half or full marathon.

In addition, running faster and stronger in the second half of the race is a much more enjoyable experience than crashing and slogging through the final miles.

Negatives

The best-laid plans of runners often go awry. You need to be able to accurately stay on pace in order to even attempt negative splits. You should use a timing app or Garmin to ensure you are on the pace you are aiming for.

Running a little bit slower early in a long distance race can be difficult because you'll feel full of energy and you may feel frustrated that other runners are passing you. Running a negative split half or full marathon requires a lot of patience and can be a difficult mental challenge to pull off.

Another drawback is that the course terrain or conditions may not be conducive to running a negative split. While you may have held back for the first half of the course, you may discover that wind, heat, dehydration, hills, runner's trots or other factors are rearing their ugly heads on the back half of the course. Now you can't speed up to your intended negative split pace.

Practice Negative Splits

If you plan to use a negative split pacing strategy on race day, practice it in your training runs. Aim to finish some of your long runs by picking up the pace for the second half of your run.

You can use the strategy with some of your shorter runs, too. Once a week, do one of your shorter runs at easy pace for the first half and pick it up to your intended marathon pace for the second half. Finishing strong during training runs not only prepares you mentally and physically to run a negative split on race day, but it will also boost your overall running confidence.

Source:

Santos-Lozano A, Collado PS, Foster C, Lucia A, Garatachea N. Influence of sex and level on marathon pacing strategy. Insights from the New York City race. Int J Sports Med. 2014 Oct;35(11):933-8. doi: 10.1055/s-0034-1367048.

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