Intervalsconfidence 0.83
5 × 1.4km
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
5 × 1.4km
Distance
16.5 km
Moving
70:00
Rep pace
3:38/km
Avg HR
163 bpm
Reps
5
Planned vs actual · TrainingPeaksPlanned 1:11:00Ran 1:10:00 · 16.5 kmIF 1.33TSS 203
Shape of the sessionEasyWorkFastest
warm up
cool down
0:005 × work / float70:00
The decode
A five-rep threshold set with five-minute jog recoveries was designed to expose a sustained effort and its heart-rate response. Equal work and recovery durations kept the session controlled, while the threshold demand accumulated across the set.
The first four reps held between 3:36/km and 3:38/km as heart rate rose from 172 to 176, then the fifth slowed to 3:42/km at 173. The pace held together through four reps before fading on the final effort.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 5:01 | 3:37/km | 172 | 4:60 |
| 2 | 5:00 | 3:37/km | 173 | 4:60 |
| 3 | 5:01 | 3:36/km | 176 | 5:00 |
| 4 | 5:02 | 3:38/km | 175 | 5:01 |
| 5 | 5:01 | 3:42/km | 173 | 9:54 |
0.83
confidence
What the engine saw
- 5 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 359s.
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
Recovery6%
Z2
Endurance10%
Z3
Tempo38%
Z4
Threshold18%
Z5
VO₂max28%
Pace
Z1
Easy24%
Z2
Endurance40%
Z3
Tempo7%
Z4
Threshold29%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery0%
Z2
Endurance9%
Z3
Tempo56%
Z4
Threshold35%
Z5
VO₂max0%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+5.1%
Effort & efficiency
0.77
Running effectiveness
speed per watt/kg, reps
6.0 w/kg
Power-to-weight
rep average
2.46
Efficiency factor
norm. power per bpm
1.02
Variability index
1.0 = perfectly even power
1.0%
Rep consistency
pace spread across reps, lower is tighter
1749 kJ
Total work
mechanical energy
1145 kcal
Energy
estimated burn
728 bpk
Cardiac cost
heartbeats per km
46%
Above threshold
≥ 164 bpm (Z4+)
+0:03/km
Split balance
positive split, slower 2nd half
Conditions-adjusted pace27°C
Actual
3:38/km
Grade-adjusted
3:38/km
Heat-adjusted
3:28/km
−10s/km
True effort
3:28/km
−10s/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.