Intervalsconfidence 0.83
4 × 1km
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
4 × 1km
Distance
10.8 km
Moving
65:48
Rep pace
5:14/km
Avg HR
143 bpm
Reps
4
Planned vs actual · TrainingPeaksPlanned not setRan 1:05:48 · 10.8 kmIF 1.02TSS 114
Shape of the sessionEasyWorkFastest
cool down
0:004 × work / float65:48
The decode
It was a four-repetition interval set: 4 × 1km, with recoveries averaging 417s.
The reps ran in 5:18, 5:24, 4:55 and 5:17, for 4000m in 20:54 at 5:13/km. Heart rate was 127, 140, 138 and 134, and the set finished at 5:17/km.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 5:18 | 5:18/km | 127 | — |
| 2 | 5:24 | 5:24/km | 140 | — |
| 3 | 4:55 | 4:55/km | 138 | — |
| 4 | 5:17 | 5:17/km | 134 | 6:57 |
0.83
confidence
What the engine saw
- 4 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 417s.
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
Recovery52%
Z2
Endurance23%
Z3
Tempo16%
Z4
Threshold8%
Z5
VO₂max0%
Pace
Z1
Easy92%
Z2
Endurance7%
Z3
Tempo0%
Z4
Threshold0%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery23%
Z2
Endurance52%
Z3
Tempo13%
Z4
Threshold12%
Z5
VO₂max1%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+13.2%
Effort & efficiency
0.70
Running effectiveness
speed per watt/kg, reps
4.6 w/kg
Power-to-weight
rep average
2.18
Efficiency factor
norm. power per bpm
1.06
Variability index
1.0 = perfectly even power
3.5%
Rep consistency
pace spread across reps, lower is tighter
1386 kJ
Total work
mechanical energy
880 kcal
Energy
estimated burn
992 bpk
Cardiac cost
heartbeats per km
8%
Above threshold
≥ 164 bpm (Z4+)
+1:05/km
Split balance
positive split, slower 2nd half
Conditions-adjusted pace28°C · +66 m
Actual
5:13/km
Grade-adjusted
5:13/km
Heat-adjusted
4:58/km
−15s/km
True effort
4:58/km
−15s/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.