Intervalsconfidence 0.83
3 × 1km
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
3 × 1km
Distance
7.7 km
Moving
37:37
Rep pace
3:41/km
Avg HR
154 bpm
Reps
3
Shape of the sessionEasyWorkFastest
warm up
cool down
0:003 × work / float37:37
The decode
It was a three-repetition interval session, with a 1851 m warmup, three 1000 m work intervals, and a 2608 m cooldown.
The reps ran in 3:31/km, 3:45/km and 3:46/km, with heart rate rising from 162 to 169 and then holding at 169. The 3000 m work segment averaged 3:41/km, followed by 261 m at 3:40/km.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 3:31 | 3:31/km | 162 | — |
| 2 | 3:45 | 3:45/km | 169 | — |
| 3 | 3:46 | 3:46/km | 169 | — |
0.83
confidence
What the engine saw
- 3 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
Recovery12%
Z2
Endurance40%
Z3
Tempo21%
Z4
Threshold27%
Z5
VO₂max1%
Pace
Z1
Easy68%
Z2
Endurance0%
Z3
Tempo19%
Z4
Threshold11%
Z5
VO₂max2%
Z6
Speed0%
Power
Z1
Recovery8%
Z2
Endurance56%
Z3
Tempo4%
Z4
Threshold18%
Z5
VO₂max14%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+3.4%
Effort & efficiency
0.71
Running effectiveness
speed per watt/kg, reps
6.4 w/kg
Power-to-weight
rep average
2.55
Efficiency factor
norm. power per bpm
1.10
Variability index
1.0 = perfectly even power
3.0%
Rep consistency
pace spread across reps, lower is tighter
808 kJ
Total work
mechanical energy
541 kcal
Energy
estimated burn
752 bpk
Cardiac cost
heartbeats per km
28%
Above threshold
≥ 164 bpm (Z4+)
+0:20/km
Split balance
positive split, slower 2nd half
Conditions-adjusted pace21°C · +7 m
Actual
3:41/km
Grade-adjusted
3:41/km
Heat-adjusted
3:35/km
−6s/km
True effort
3:35/km
−6s/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.