How do people actually pace a marathon?
The most common pattern is pronounced slowing: 46.9% of eligible finishes. The full-course profile also shows how pace changes within those broad blocks.
Calculated directly from 3,517,336 complete, plausible split records in the public export.
How we measured it. For each runner, divide section pace by their full-marathon average pace and subtract one. Plot the median of these individual percentages at each checkpoint; zero is that runner’s own marathon pace. A median curve is not itself one runner’s race and need not integrate to zero.
Full methodology & sources
Compare elapsed time over 0–12.43 mi with 12.43–24.85 mi. Faster: more than 2% faster; similar: within 2%; moderate slowing: more than 2% through 10%; pronounced slowing: more than 10%. The final 1.36 mi appears in the profile but not this equal-distance classification. These are descriptive categories, not slowdown episodes or measured half-marathon splits.
Use complete, strictly increasing elapsed checkpoints at 3.11, 6.21, 9.32, 12.43, 15.53, 18.64, 21.75, 24.85 and 26.22 mi. Clock strings must parse as H:MM:SS or M:SS. No missing splits are interpolated.
Remove exact duplicate race records, ignoring database IDs, ingestion timestamps and source URLs. Retain finishes from 90 minutes to 12 hours with every section between 3.22 and 32.19 minutes/mi. These quality filters can exclude genuine unusual performances; the analysis describes this eligible cohort, not every entrant.
Each observation is a race finish. The same person can appear in multiple races. No runner identities are linked across races. Public cells require at least 100 observations; matched comparisons additionally require at least 20 per group in each stratum.
Apply the reviewed source-quality edition exclusions for this exact export after the timing checks. Known invalid split grids, incomplete ingestion, unreconciled HOLD editions and a selected top-finisher field do not contribute to the analyses or prior benchmarks. Report source exclusions separately; an already invalid timing row is not counted twice. Missing age or recorded gender alone does not exclude an otherwise eligible finish from the overall cohort. Other sparse editions are not declared incomplete merely from their size.
The typical pace profile
Pace difference (%) · higher is slower
Points average the preceding section. The final section is 24.85–26.22 mi; lines do not locate pace changes within a section.
Median of individually normalized section paces. Below zero is faster than the runner’s own marathon average.
View exact values and sample sizes
| Course section | The typical pace profile | Observations |
|---|---|---|
| 0–3.11 mi | -5.1% | 3,517,336 |
| 3.11–6.21 mi | -5.8% | 3,517,336 |
| 6.21–9.32 mi | -4.9% | 3,517,336 |
| 9.32–12.43 mi | -3.4% | 3,517,336 |
| 12.43–15.53 mi | -0.9% | 3,517,336 |
| 15.53–18.64 mi | 1.1% | 3,517,336 |
| 18.64–21.75 mi | 5.3% | 3,517,336 |
| 21.75–24.85 mi | 8.9% | 3,517,336 |
| 24.85–26.22 mi | 4.4% | 3,517,336 |
How the second 12.43 mi compares with the first
Percent (%)
The final 1.36 mi is excluded from this equal-distance comparison.
View exact values and sample sizes
| Group | How the second 12.43 mi compares with the first | Observations |
|---|---|---|
| Faster second 12.43 mi | 3.9% | 3,517,336 |
| Similar 12.43 mi blocks | 14.4% | 3,517,336 |
| Moderate slowing | 34.8% | 3,517,336 |
| Pronounced slowing | 46.9% | 3,517,336 |