Intervalsconfidence 0.83
4 × 1km
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
4 × 1km
Distance
13.2 km
Moving
60:35
Rep pace
3:54/km
Avg HR
153 bpm
Reps
4
Planned vs actual · TrainingPeaksPlanned not setRan 1:00:35 · 13.2 kmIF 1.33TSS 177
Shape of the sessionEasyWorkFastest
warm up
cool down
0:004 × work / float60:35
The decode
This was a two-block tempo session built around 10-minute efforts, with a 5:00 recovery between them.
The four 1 km work reps moved from 3:55/km to 3:53/km, with heart rate rising from 165 to 176 and the set holding together.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 3:55 | 3:55/km | 165 | — |
| 2 | 3:55 | 3:55/km | 172 | — |
| 3 | 3:53 | 3:53/km | 170 | — |
| 4 | 3:53 | 3:53/km | 176 | — |
0.83
confidence
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).
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
Recovery27%
Z2
Endurance39%
Z3
Tempo8%
Z4
Threshold15%
Z5
VO₂max11%
Pace
Z1
Easy42%
Z2
Endurance32%
Z3
Tempo25%
Z4
Threshold1%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery0%
Z2
Endurance21%
Z3
Tempo49%
Z4
Threshold23%
Z5
VO₂max6%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR-0.4%
Effort & efficiency
0.71
Running effectiveness
speed per watt/kg, reps
6.0 w/kg
Power-to-weight
rep average
2.65
Efficiency factor
norm. power per bpm
1.03
Variability index
1.0 = perfectly even power
0.4%
Rep consistency
pace spread across reps, lower is tighter
1733 kJ
Total work
mechanical energy
932 kcal
Energy
estimated burn
865 bpk
Cardiac cost
heartbeats per km
27%
Above threshold
≥ 164 bpm (Z4+)
-0:43/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace24°C · +50 m
Actual
3:54/km
Grade-adjusted
3:54/km
Heat-adjusted
3:46/km
−8s/km
True effort
3:46/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.