Intervalsconfidence 0.83
6 × 1km
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
6 × 1km
Distance
21.2 km
Moving
99:30
Rep pace
4:02/km
Avg HR
159 bpm
Reps
6
Shape of the sessionEasyWorkFastest
cool down
0:006 × work / float99:30
The decode
Six 1km reps formed a cut-down interval session. The 349-second average recoveries separated the efforts, while the structure demanded faster running late rather than simple repetition.
The pace moved from 4:05/km and 4:04/km to 4:14/km, then sharpened through 4:02/km, 3:54/km and 3:53/km. Heart rate peaked at 195 on rep two, fell to 165 on rep three, then held at 157, 157 and 159 for the final three reps.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 4:05 | 4:05/km | 176 | — |
| 2 | 4:04 | 4:04/km | 195 | — |
| 3 | 4:14 | 4:14/km | 165 | — |
| 4 | 4:02 | 4:02/km | 157 | — |
| 5 | 3:54 | 3:54/km | 157 | — |
| 6 | 3:53 | 3:53/km | 159 | 5:49 |
0.83
confidence
What the engine saw
- 6 work intervals detected from lap markers, confirmed by clear pace separation.
- Rep paces descend across the set (a cut-down / progression).
- Recoveries average 349s.
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
Heart rate
Z1
Recovery2%
Z2
Endurance12%
Z3
Tempo35%
Z4
Threshold47%
Z5
VO₂max4%
Pace
Z1
Easy26%
Z2
Endurance60%
Z3
Tempo14%
Z4
Threshold0%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery0%
Z2
Endurance8%
Z3
Tempo75%
Z4
Threshold15%
Z5
VO₂max2%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+3.9%
Effort & efficiency
0.74
Running effectiveness
speed per watt/kg, reps
5.6 w/kg
Power-to-weight
rep average
2.50
Efficiency factor
norm. power per bpm
1.02
Variability index
1.0 = perfectly even power
2.9%
Rep consistency
pace spread across reps, lower is tighter
4292 kJ
Total work
mechanical energy
1473 kcal
Energy
estimated burn
1449 bpk
Cardiac cost
heartbeats per km
51%
Above threshold
≥ 164 bpm (Z4+)
+0:21/km
Split balance
positive split, slower 2nd half
Conditions-adjusted pace23°C · +81 m
Actual
4:02/km
Grade-adjusted
4:02/km
Heat-adjusted
3:54/km
−8s/km
True effort
3:54/km
−8s/km
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.