Intervalsconfidence 0.83
4 × 1km
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
4 × 1km
Distance
10.5 km
Moving
62:34
Rep pace
5:01/km
Avg HR
164 bpm
Reps
4
Shape of the sessionEasyWorkFastest
warm up
0:004 × work / float62:34
The decode
This was a four-repetition interval set over 1,000 m reps, with recoveries averaging 345s.
The reps ran at 5:11/km, 4:57/km, 5:10/km, and 4:44/km. Heart rate rose from 145 to 174 across the set.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 5:11 | 5:11/km | 145 | — |
| 2 | 4:57 | 4:57/km | 151 | 5:45 |
| 3 | 5:10 | 5:10/km | 163 | — |
| 4 | 4:44 | 4:44/km | 174 | — |
0.83
confidence
What the engine saw
- 4 work intervals detected from lap markers, confirmed by clear pace separation.
- Rep paces descend across the set (a cut-down / progression).
- Recoveries average 345s.
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
Recovery9%
Z2
Endurance12%
Z3
Tempo20%
Z4
Threshold26%
Z5
VO₂max33%
Pace
Z1
Easy78%
Z2
Endurance22%
Z3
Tempo1%
Z4
Threshold0%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery42%
Z2
Endurance19%
Z3
Tempo25%
Z4
Threshold14%
Z5
VO₂max0%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+10%
Effort & efficiency
0.67
Running effectiveness
speed per watt/kg, reps
5.0 w/kg
Power-to-weight
rep average
2.08
Efficiency factor
norm. power per bpm
1.11
Variability index
1.0 = perfectly even power
3.7%
Rep consistency
pace spread across reps, lower is tighter
1324 kJ
Total work
mechanical energy
962 kcal
Energy
estimated burn
1109 bpk
Cardiac cost
heartbeats per km
59%
Above threshold
≥ 164 bpm (Z4+)
+0:38/km
Split balance
positive split, slower 2nd half
Conditions-adjusted pace25°C · +85 m
Actual
5:00/km
Grade-adjusted
5:00/km
Heat-adjusted
4:48/km
−12s/km
True effort
4:48/km
−12s/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.