4 × 200m
Source: own Strava export
A descending fartlek set with four work blocks was designed to move from 5k-paced longer efforts to faster short reps, then carry that speed into a 20-minute marathon-pace close. Jog recoveries kept the work continuous and prevented the session from becoming a series of isolated sprints.
The pace sharpened as the efforts shortened, reaching 3:04/km on the first 30-second rep and 2:53/km on the first 15-second rep, before fading to 3:12/km and 3:11/km respectively. Heart rate rose from 172 on the first 30-second rep to 180 on the second and 182 in the 15-second block. The 20-minute close at 4:02/km and HR 174 kept the session anchored in sustained running rather than pure speed.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 0:30 | 3:04/km | 172 | 0:30 |
| 2 | 0:30 | 3:08/km | 180 | 0:30 |
| 3 | 0:30 | 3:08/km | 179 | 0:30 |
| 4 | 0:30 | 3:12/km | 179 | 0:30 |
What the engine saw
- 4 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 30s.
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. Adjustments are modest on this one; on a hot day or a hilly route this is where the real work hides.