Intervalsconfidence 0.83
4 × 1km
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
4 × 1km
Distance
11.6 km
Moving
70:21
Rep pace
5:12/km
Avg HR
150 bpm
Reps
4
Planned vs actual · TrainingPeaksPlanned 10.0 kmRan 1:10:21 · 11.6 kmIF 1.02TSS 121
Shape of the sessionEasyWorkFastest
cool down
0:004 × work / float70:21
The decode
This was a sand run structured around 1.5 km easy, 7 km on sand, and 1.5 km easy.
The recorded 4,000 m work segment averaged 5:12/km, with 1,000 m efforts of 5:17/km, 5:13/km, 5:14/km and 5:04/km. Heart rate was 128, 139, 138 and 137 across the four efforts.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 5:17 | 5:17/km | 128 | — |
| 2 | 5:13 | 5:13/km | 139 | — |
| 3 | 5:14 | 5:14/km | 138 | — |
| 4 | 5:04 | 5:04/km | 137 | 6:01 |
0.83
confidence
What the engine saw
- 4 work intervals detected from lap markers, confirmed by clear pace separation.
- Rep paces descend across the set (a cut-down / progression).
- Recoveries average 361s.
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
Recovery42%
Z2
Endurance14%
Z3
Tempo28%
Z4
Threshold15%
Z5
VO₂max0%
Pace
Z1
Easy83%
Z2
Endurance17%
Z3
Tempo0%
Z4
Threshold0%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery20%
Z2
Endurance53%
Z3
Tempo7%
Z4
Threshold19%
Z5
VO₂max1%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+24%
Effort & efficiency
0.68
Running effectiveness
speed per watt/kg, reps
4.7 w/kg
Power-to-weight
rep average
2.08
Efficiency factor
norm. power per bpm
1.06
Variability index
1.0 = perfectly even power
1.5%
Rep consistency
pace spread across reps, lower is tighter
1628 kJ
Total work
mechanical energy
1007 kcal
Energy
estimated burn
1101 bpk
Cardiac cost
heartbeats per km
15%
Above threshold
≥ 164 bpm (Z4+)
+1:12/km
Split balance
positive split, slower 2nd half
Conditions-adjusted pace28°C · +71 m
Actual
5:12/km
Grade-adjusted
5:12/km
Heat-adjusted
4:57/km
−15s/km
True effort
4:57/km
−15s/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.