3k threshold + 5 × 800m
3k threshold 5 × 800m
Source: own Strava export
A two-part quality session: a single 3 km block at threshold, then five 800 m repetitions off short 200 m floats. The threshold rep ran 3:44/km at HR 172, right at the top of the aerobic band; the 800s dropped to roughly 3:33/km with power on the reps around 495 to 515 W, comfortably above the ~465 W running threshold and into the VO₂ band. Pairing a sustained threshold block with shorter, faster reps trains two systems in one outing, the steady strength of threshold and the turnover of VO₂-range running.
The 800s were strikingly even, several within a second per km of each other, heart rate climbing from 172 to a 177 ceiling and holding rather than spiking. Cadence lifted from about 86 on the steady running to 92 on the reps, the usual tell of dropping into race gear. The day was warm at around 23°C, which nudges the true cost of the faster reps a little above what the raw splits show.
The gap between the threshold rep (HR 172) and the 800s (HR 177) is narrow, so there is room to separate the two stimuli more sharply, either by running the threshold block a touch harder or the 800s a touch faster. For a 50 km build this is exactly the kind of session that keeps leg speed alive while the long runs carry the endurance load.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 2:49 | 3:31/km | 176 | 0:58 |
| 2 | 2:52 | 3:35/km | 177 | 1:04 |
| 3 | 3:00 | 3:45/km | 173 | 1:05 |
| 4 | 2:54 | 3:37/km | 176 | 1:04 |
| 5 | 2:54 | 3:37/km | 175 | 1:01 |
Pace & heart rate
What the engine saw
- 5 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 62s.
- Matches the athlete's own session label.
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%.
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.
More decodes
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