Intervalsconfidence 0.83
3 × 1km
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
3 × 1km
Distance
9.6 km
Moving
45:50
Rep pace
3:52/km
Avg HR
153 bpm
Reps
3
Shape of the sessionEasyWorkFastest
warm up
cool down
0:003 × work / float45:50
The decode
It was a 3 × 1km interval set with recoveries between the work intervals.
The reps ran 3:58/km, 3:45/km and 3:53/km. Heart rate was 157, 179 and 168, with the fastest rep also producing the highest reading.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 3:58 | 3:58/km | 157 | — |
| 2 | 3:45 | 3:45/km | 179 | 5:02 |
| 3 | 3:53 | 3:53/km | 168 | 2:04 |
0.83
confidence
What the engine saw
- 3 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 213s.
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
Recovery23%
Z2
Endurance35%
Z3
Tempo15%
Z4
Threshold17%
Z5
VO₂max11%
Pace
Z1
Easy60%
Z2
Endurance6%
Z3
Tempo28%
Z4
Threshold6%
Z5
VO₂max0%
Z6
Speed1%
Power
Z1
Recovery7%
Z2
Endurance31%
Z3
Tempo23%
Z4
Threshold29%
Z5
VO₂max10%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR-3.2%
Effort & efficiency
0.72
Running effectiveness
speed per watt/kg, reps
6.0 w/kg
Power-to-weight
rep average
2.66
Efficiency factor
norm. power per bpm
1.08
Variability index
1.0 = perfectly even power
2.3%
Rep consistency
pace spread across reps, lower is tighter
1119 kJ
Total work
mechanical energy
680 kcal
Energy
estimated burn
794 bpk
Cardiac cost
heartbeats per km
27%
Above threshold
≥ 164 bpm (Z4+)
-0:44/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace15°C · +34 m
Actual
3:52/km
Grade-adjusted
3:52/km
Heat-adjusted
3:52/km
True effort
3:52/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.