Intervalsconfidence 0.83
5 × 900m
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
5 × 900m
Distance
5.6 km
Moving
29:41
Rep pace
4:02/km
Avg HR
145 bpm
Reps
5
Shape of the sessionEasyWorkFastest
cool down
0:005 × work / float29:41
The decode
It was a five-repetition interval set with recoveries averaging 138s.
The work progressed from 4:33/km to 3:35/km across the set, with heart rate rising from 134 to 162 while the cut-down held together.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 4:20 | 4:33/km | 134 | 1:51 |
| 2 | 3:57 | 4:15/km | 149 | 2:39 |
| 3 | 3:29 | 4:01/km | 148 | 2:15 |
| 4 | 3:18 | 3:45/km | 156 | 2:58 |
| 5 | 3:04 | 3:35/km | 162 | 1:50 |
0.83
confidence
What the engine saw
- 5 work intervals detected from lap markers, confirmed by clear pace separation.
- Rep paces descend across the set (a cut-down / progression).
- Recoveries average 138s.
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
Recovery40%
Z2
Endurance19%
Z3
Tempo26%
Z4
Threshold15%
Z5
VO₂max1%
Pace
Z1
Easy39%
Z2
Endurance27%
Z3
Tempo17%
Z4
Threshold12%
Z5
VO₂max6%
Z6
Speed0%
Power
Z1
Recovery35%
Z2
Endurance3%
Z3
Tempo32%
Z4
Threshold31%
Z5
VO₂max0%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+9%
Effort & efficiency
0.76
Running effectiveness
speed per watt/kg, reps
5.5 w/kg
Power-to-weight
rep average
2.58
Efficiency factor
norm. power per bpm
1.22
Variability index
1.0 = perfectly even power
8.6%
Rep consistency
pace spread across reps, lower is tighter
547 kJ
Total work
mechanical energy
379 kcal
Energy
estimated burn
762 bpk
Cardiac cost
heartbeats per km
16%
Above threshold
≥ 164 bpm (Z4+)
+0:05/km
Split balance
positive split, slower 2nd half
Conditions-adjusted pace25°C
Actual
4:00/km
Grade-adjusted
4:00/km
Heat-adjusted
3:51/km
−9s/km
True effort
3:51/km
−9s/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.