Intervalsconfidence 0.88
4 × 6-min
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
4 × 6-min
Distance
9.6 km
Moving
40:34
Rep pace
3:46/km
Avg HR
163 bpm
Reps
8
Planned vs actual · TrainingPeaksPlanned not setRan 40:34 · 9.6 kmIF 1.41TSS 133
Shape of the sessionEasyWorkFastest
warm up
cool down
0:008 × work / float40:34
The decode
It was a four-by-six-minute interval set with 1:00 recoveries between the work blocks.
The work blocks ran at 3:45/km, 3:43/km, 3:47/km and 3:47/km. Heart rate moved from 166 to 170, 166 and 173 across the set, with the pace holding at 3:47/km for the final two blocks.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 3:43 | 3:43/km | 166 | — |
| 2 | 2:17 | 3:48/km | 171 | 1:00 |
| 3 | 3:40 | 3:40/km | 170 | — |
| 4 | 2:20 | 3:49/km | 176 | 1:00 |
| 5 | 3:47 | 3:47/km | 166 | — |
| 6 | 2:13 | 3:48/km | 175 | 1:00 |
| 7 | 3:48 | 3:48/km | 173 | — |
| 8 | 2:12 | 3:46/km | 178 | 1:00 |
0.88
confidence
What the engine saw
- 8 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 60s.
- Matches the athlete's own session label.
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
Recovery6%
Z2
Endurance25%
Z3
Tempo9%
Z4
Threshold36%
Z5
VO₂max24%
Pace
Z1
Easy37%
Z2
Endurance6%
Z3
Tempo49%
Z4
Threshold7%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery0%
Z2
Endurance22%
Z3
Tempo25%
Z4
Threshold44%
Z5
VO₂max9%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR0%
Effort & efficiency
0.73
Running effectiveness
speed per watt/kg, reps
6.0 w/kg
Power-to-weight
rep average
2.63
Efficiency factor
norm. power per bpm
1.03
Variability index
1.0 = perfectly even power
1.2%
Rep consistency
pace spread across reps, lower is tighter
1041 kJ
Total work
mechanical energy
663 kcal
Energy
estimated burn
714 bpk
Cardiac cost
heartbeats per km
60%
Above threshold
≥ 164 bpm (Z4+)
-0:23/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace32°C · +48 m
Actual
3:46/km
Grade-adjusted
3:46/km
Heat-adjusted
3:32/km
−14s/km
True effort
3:32/km
−14s/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.