2k / 1.6k / 1.2k + 800m + 4 × 400m
Source: own Strava export
A descending threshold-to-VO2 session moved from controlled sustained work into faster repetitions. The narrowing structure increased speed demand while the short recoveries preserved residual load between efforts.
The threshold blocks quickened from 3:44/km to 3:41/km and 3:37/km, before the 800m rep at 3:30/km led into 400m repetitions at 3:22/km, 3:18/km, 3:23/km and 3:23/km. Heart rate reached 170 on the 800m and rose to 176 on the final 400m; the speed set held together despite that rising response.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 2:48 | 3:30/km | 170 | 1:53 |
| 2 | 1:21 | 3:22/km | 167 | 0:45 |
| 3 | 1:19 | 3:18/km | 170 | 0:45 |
| 4 | 1:21 | 3:23/km | 173 | 0:45 |
| 5 | 1:21 | 3:23/km | 176 | 0:45 |
What the engine saw
- 5 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 59s.
Calibration flags
- Running power threshold estimated from the athlete's half-marathon best efforts (60-min power 476 W, 95% of 20-min power 460 W). Treat power zones and load as ±3%.
- Zones and running threshold are one snapshot, read 2 Jul 2026 and applied to every session in the archive. An older session is scored against today's zones, not the zones the athlete trained with then.
Engine read · editorial decode by Splits
Time in zone
The rep pace re-expressed for flat ground and cool air, the effort, not the clock. The gap between actual and true effort is the day's hidden work: conditions were taxing the clock.