Intervalsconfidence 0.83
3 × 1.6km
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
3 × 1.6km
Distance
10.3 km
Moving
47:35
Rep pace
3:38/km
Avg HR
150 bpm
Reps
3
Planned vs actual · TrainingPeaksPlanned 10.0 kmRan 47:35 · 10.3 kmIF 1.33TSS 138
Shape of the sessionEasyWorkFastest
warm up
cool down
0:003 × work / float47:35
The decode
The session was a three-repetition interval set of 1609m, with reps long enough to avoid constant pace changes within each effort.
The first two reps matched at 5:46 and 3:35/km, before the third slowed to 5:59 and 3:43/km. Heart rate fell from 175 to 162 to 154 across the reps.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 5:46 | 3:35/km | 175 | 1:30 |
| 2 | 5:46 | 3:35/km | 162 | 0:54 |
| 3 | 5:59 | 3:43/km | 154 | 8:10 |
0.83
confidence
What the engine saw
- 3 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 212s.
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
Recovery30%
Z2
Endurance40%
Z3
Tempo18%
Z4
Threshold5%
Z5
VO₂max7%
Pace
Z1
Easy67%
Z2
Endurance4%
Z3
Tempo10%
Z4
Threshold20%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery2%
Z2
Endurance51%
Z3
Tempo17%
Z4
Threshold18%
Z5
VO₂max12%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR-3.9%
Effort & efficiency
0.74
Running effectiveness
speed per watt/kg, reps
6.2 w/kg
Power-to-weight
rep average
2.69
Efficiency factor
norm. power per bpm
1.06
Variability index
1.0 = perfectly even power
1.7%
Rep consistency
pace spread across reps, lower is tighter
1298 kJ
Total work
mechanical energy
703 kcal
Energy
estimated burn
830 bpk
Cardiac cost
heartbeats per km
12%
Above threshold
≥ 164 bpm (Z4+)
-0:30/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace18°C · +20 m
Actual
3:38/km
Grade-adjusted
3:38/km
Heat-adjusted
3:35/km
−3s/km
True effort
3:35/km
−3s/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.