Intervalsconfidence 0.83
6 × 3.5min
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
6 × 3.5min
Distance
20.3 km
Moving
89:34
Rep pace
3:35/km
Avg HR
146 bpm
Reps
6
Planned vs actual · TrainingPeaksPlanned 14.0 kmRan 1:29:34 · 20.3 kmIF 1.38TSS 283
Shape of the sessionEasyWorkFastest
warm up
cool down
0:006 × work / float89:34
The decode
This was a six-repetition interval set, built around 3:30 work and 1:30 recoveries. The short recoveries demanded repeated fast running without full clearance, while the long cooldown kept the session from becoming a pure speed workout.
The first five reps stayed between 3:32/km and 3:39/km, and the shortened final rep was 3:38/km. Heart rate peaked at 160 on rep four, then fell to 143 and 146 on reps five and six, so the set did not show a rising HR trend.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 3:30 | 3:32/km | 140 | 1:30 |
| 2 | 3:30 | 3:35/km | 150 | 1:30 |
| 3 | 3:30 | 3:32/km | 150 | 1:30 |
| 4 | 3:30 | 3:39/km | 160 | 1:30 |
| 5 | 3:30 | 3:32/km | 143 | 1:30 |
| 6 | 2:36 | 3:38/km | 146 | 0:01 |
0.83
confidence
What the engine saw
- 6 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 75s.
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
Recovery21%
Z2
Endurance73%
Z3
Tempo4%
Z4
Threshold2%
Z5
VO₂max0%
Pace
Z1
Easy41%
Z2
Endurance31%
Z3
Tempo10%
Z4
Threshold17%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery1%
Z2
Endurance25%
Z3
Tempo37%
Z4
Threshold24%
Z5
VO₂max10%
Z6
Anaerobic3%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+14%
Effort & efficiency
0.75
Running effectiveness
speed per watt/kg, reps
6.2 w/kg
Power-to-weight
rep average
2.90
Efficiency factor
norm. power per bpm
1.06
Variability index
1.0 = perfectly even power
1.4%
Rep consistency
pace spread across reps, lower is tighter
2526 kJ
Total work
mechanical energy
1336 kcal
Energy
estimated burn
762 bpk
Cardiac cost
heartbeats per km
2%
Above threshold
≥ 164 bpm (Z4+)
+0:33/km
Split balance
positive split, slower 2nd half
Conditions-adjusted pace19°C · +203 m
Actual
3:35/km
Grade-adjusted
3:35/km
Heat-adjusted
3:31/km
−4s/km
True effort
3:31/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.