Negative splits, explained
By Abel Rodriguez
A negative split means running the second half of a race faster than the first. It sounds simple, and it is the single most dependable pacing strategy for anything from a 5K to a marathon.
Why it works#
Early miles feel easy because you are fresh and tapered, and that is exactly when it is easiest to overspend. Every second you bank early tends to cost two later.
The first half of a marathon should feel almost boring. If it feels good, you are probably running it right.
How much slower to start#
You do not need a dramatic difference. A gentle ramp is enough:
- 5K and 10K: start 1 to 2% slower than goal pace
- Half marathon: start 2 to 3% slower
- Marathon: start 3 to 4% slower, then ease down in the final 10K
Try your own numbers in the Splits tool: set your goal time, drag the slider toward Fast finish, and see what each kilometer should look like.