Intervalsconfidence 0.83
4 × 1km
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
4 × 1km
Distance
11.3 km
Moving
49:50
Rep pace
3:56/km
Avg HR
144 bpm
Reps
4
Shape of the sessionEasyWorkFastest
warm up
0:004 × work / float49:50
The decode
It was a four-repetition interval session, with 1km work bouts after 7km of warmup.
The reps ran 4:04/km, 3:51/km, 3:52/km and 3:56/km. Heart rate was 157, 159, 157 and 157, with the set holding between 3:51/km and 3:56/km after the opening rep.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 4:04 | 4:04/km | 157 | — |
| 2 | 3:51 | 3:51/km | 159 | — |
| 3 | 3:52 | 3:52/km | 157 | — |
| 4 | 3:56 | 3:56/km | 157 | — |
0.83
confidence
What the engine saw
- 4 work intervals detected from lap markers, confirmed by clear pace separation.
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
Recovery45%
Z2
Endurance23%
Z3
Tempo31%
Z4
Threshold0%
Z5
VO₂max0%
Pace
Z1
Easy25%
Z2
Endurance50%
Z3
Tempo24%
Z4
Threshold0%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery0%
Z2
Endurance8%
Z3
Tempo33%
Z4
Threshold53%
Z5
VO₂max5%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR-0.5%
Effort & efficiency
0.72
Running effectiveness
speed per watt/kg, reps
5.9 w/kg
Power-to-weight
rep average
2.92
Efficiency factor
norm. power per bpm
1.02
Variability index
1.0 = perfectly even power
2.2%
Rep consistency
pace spread across reps, lower is tighter
1481 kJ
Total work
mechanical energy
795 kcal
Energy
estimated burn
749 bpk
Cardiac cost
heartbeats per km
0%
Above threshold
≥ 164 bpm (Z4+)
-0:38/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace21°C · +52 m
Actual
3:55/km
Grade-adjusted
3:55/km
Heat-adjusted
3:50/km
−5s/km
True effort
3:50/km
−5s/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.