Intervalsconfidence 0.83
3 × 2.1km
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
3 × 2.1km
Distance
18.4 km
Moving
84:48
Rep pace
3:44/km
Avg HR
151 bpm
Reps
3
Planned vs actual · TrainingPeaksPlanned 59:44 · 14.0 kmRan 1:24:48 · 18.4 kmIF 1.34TSS 253
Shape of the sessionEasyWorkFastest
warm up
cool down
0:003 × work / float84:48
The decode
It was a threshold set of three 8:00 work intervals with 2:00 easy recoveries.
The reps ran at 3:45/km, 3:47/km and 3:41/km, while heart rate rose from 166 to 174 to 178. The set finished with its fastest rep.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 8:00 | 3:45/km | 166 | 2:00 |
| 2 | 8:00 | 3:47/km | 174 | 2:00 |
| 3 | 8:00 | 3:41/km | 178 | 2:00 |
0.83
confidence
What the engine saw
- 3 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 120s.
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
Recovery32%
Z2
Endurance24%
Z3
Tempo6%
Z4
Threshold9%
Z5
VO₂max28%
Pace
Z1
Easy64%
Z2
Endurance14%
Z3
Tempo16%
Z4
Threshold6%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery2%
Z2
Endurance50%
Z3
Tempo20%
Z4
Threshold20%
Z5
VO₂max8%
Z6
Anaerobic1%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+5.3%
Effort & efficiency
0.74
Running effectiveness
speed per watt/kg, reps
6.1 w/kg
Power-to-weight
rep average
2.71
Efficiency factor
norm. power per bpm
1.06
Variability index
1.0 = perfectly even power
1.1%
Rep consistency
pace spread across reps, lower is tighter
2415 kJ
Total work
mechanical energy
1319 kcal
Energy
estimated burn
905 bpk
Cardiac cost
heartbeats per km
38%
Above threshold
≥ 164 bpm (Z4+)
+0:31/km
Split balance
positive split, slower 2nd half
Conditions-adjusted pace19°C · +177 m
Actual
3:45/km
Grade-adjusted
3:45/km
Heat-adjusted
3:41/km
−4s/km
True effort
3:41/km
−4s/km
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.