Intervalsconfidence 0.83
5 × 400m
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
5 × 400m
Distance
9.6 km
Moving
43:46
Rep pace
3:36/km
Avg HR
153 bpm
Reps
5
Planned vs actual · TrainingPeaksPlanned 12.0 kmRan 43:46 · 9.6 kmIF 1.36TSS 133
Shape of the sessionEasyWorkFastest
warm up
cool down
0:005 × work / float43:46
The decode
It was a five-repetition interval set, with 90-second efforts and 45-second recoveries. Three 4-minute steady segments preceded the reps.
The work paces were 3:40/km, 3:34/km, 3:37/km, 3:38/km and 3:32/km, with the final repetition fastest. Heart rate was 158, 162, 160, 170 and 166.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 1:30 | 3:40/km | 158 | 0:45 |
| 2 | 1:30 | 3:34/km | 162 | 0:45 |
| 3 | 1:30 | 3:37/km | 160 | 0:45 |
| 4 | 1:30 | 3:38/km | 170 | 0:45 |
| 5 | 1:30 | 3:32/km | 166 | 7:21 |
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 124s.
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
Recovery14%
Z2
Endurance39%
Z3
Tempo28%
Z4
Threshold20%
Z5
VO₂max0%
Pace
Z1
Easy56%
Z2
Endurance1%
Z3
Tempo22%
Z4
Threshold19%
Z5
VO₂max1%
Z6
Speed0%
Power
Z1
Recovery7%
Z2
Endurance35%
Z3
Tempo18%
Z4
Threshold16%
Z5
VO₂max20%
Z6
Anaerobic4%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+5.3%
Effort & efficiency
0.70
Running effectiveness
speed per watt/kg, reps
6.6 w/kg
Power-to-weight
rep average
2.78
Efficiency factor
norm. power per bpm
1.08
Variability index
1.0 = perfectly even power
1.3%
Rep consistency
pace spread across reps, lower is tighter
1030 kJ
Total work
mechanical energy
683 kcal
Energy
estimated burn
697 bpk
Cardiac cost
heartbeats per km
20%
Above threshold
≥ 164 bpm (Z4+)
-0:07/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace20°C · +38 m
Actual
3:36/km
Grade-adjusted
3:36/km
Heat-adjusted
3:32/km
−4s/km
True effort
3:32/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.