Intervalsconfidence 0.88
12 × 30s on / 2.5min off
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
12 × 30s on / 2.5min off
Distance
8.9 km
Moving
45:53
Rep pace
2:49/km
Avg HR
146 bpm
Reps
12
Planned vs actual · TrainingPeaksPlanned 12.0 kmRan 45:53 · 8.9 kmIF 1.17TSS 104
Shape of the sessionEasyWorkFastest
warm up
cool down
0:0012 × work / float45:53
The decode
This was a 12-rep sprint set: 30s work bouts separated by 2:30 recoveries.
The reps covered 155m to 195m at 2:34/km to 3:13/km. Reps 7-10 slowed to 3:03, 3:09, 2:50 and 3:13/km before the final two returned to 2:41 and 2:39/km. Heart rate reached 156 on rep 3 and was 146 and 148 on the final two.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 0:30 | 2:40/km | 125 | 2:30 |
| 2 | 0:30 | 2:42/km | 147 | 2:30 |
| 3 | 0:30 | 2:54/km | 156 | 2:30 |
| 4 | 0:30 | 2:34/km | 142 | 2:30 |
| 5 | 0:30 | 2:47/km | 149 | 2:30 |
| 6 | 0:30 | 2:41/km | 149 | 2:30 |
| 7 | 0:30 | 3:03/km | 151 | 2:30 |
| 8 | 0:30 | 3:09/km | 151 | 2:30 |
| 9 | 0:30 | 2:50/km | 145 | 2:30 |
| 10 | 0:30 | 3:13/km | 153 | 2:30 |
| 11 | 0:30 | 2:41/km | 146 | 2:30 |
| 12 | 0:30 | 2:39/km | 148 | 2:24 |
0.88
confidence
What the engine saw
- 12 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 149s.
- 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
Recovery27%
Z2
Endurance60%
Z3
Tempo12%
Z4
Threshold0%
Z5
VO₂max0%
Pace
Z1
Easy82%
Z2
Endurance3%
Z3
Tempo1%
Z4
Threshold2%
Z5
VO₂max0%
Z6
Speed11%
Power
Z1
Recovery11%
Z2
Endurance63%
Z3
Tempo12%
Z4
Threshold2%
Z5
VO₂max3%
Z6
Anaerobic9%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+8.9%
Effort & efficiency
0.91
Running effectiveness
speed per watt/kg, reps
6.5 w/kg
Power-to-weight
rep average
2.59
Efficiency factor
norm. power per bpm
1.13
Variability index
1.0 = perfectly even power
7.1%
Rep consistency
pace spread across reps, lower is tighter
950 kJ
Total work
mechanical energy
672 kcal
Energy
estimated burn
772 bpk
Cardiac cost
heartbeats per km
0%
Above threshold
≥ 164 bpm (Z4+)
+0:17/km
Split balance
positive split, slower 2nd half
Conditions-adjusted pace20°C · +22 m
Actual
2:49/km
Grade-adjusted
2:49/km
Heat-adjusted
2:45/km
−4s/km
True effort
2:45/km
−4s/km
The rep pace re-expressed for flat ground and cool air, the effort, not the clock. Adjustments are modest on this one; on a hot day or a hilly route this is where the real work hides.