4 × 300m
Source: own Strava export
A speed-to-threshold interval session moved from one-minute speed reps into four 10-minute blocks. The sequencing demanded a clean change of gear, with two-minute jogs after the opening reps and three-minute jogs between the longer efforts; the shorter recoveries kept the first set mechanically sharp, while the longer recoveries reset the second set.
The one-minute reps ran 3:15/km, 3:13/km, 3:11/km and 3:13/km, with heart rate rising from 155 to 169 before settling at 164 and 168. The 10-minute blocks progressed from 3:51/km to 3:50/km, 3:50/km and 3:45/km, with heart rate at 178, 176, 178 and 176. The longer work held together and finished faster.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 1:00 | 3:15/km | 155 | 2:00 |
| 2 | 1:00 | 3:13/km | 169 | 2:00 |
| 3 | 1:00 | 3:11/km | 164 | 2:00 |
| 4 | 1:00 | 3:13/km | 168 | 2:00 |
What the engine saw
- 4 work intervals detected from lap markers, confirmed by clear pace separation.
- Rep paces descend across the set (a cut-down / progression).
- Recoveries average 120s.
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.