Intervalsconfidence 0.83
4 × 1km
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
4 × 1km
Distance
9.7 km
Moving
40:38
Rep pace
3:44/km
Avg HR
146 bpm
Reps
4
Planned vs actual · TrainingPeaksPlanned 54:33 · 12.0 kmRan 40:38 · 9.7 kmIF 1.43TSS 136
Shape of the sessionEasyWorkFastest
warm up
cool down
0:004 × work / float40:38
The decode
The session used four five-minute efforts at half-marathon pace, with two-minute jog recoveries, between a warm-up and cooldown.
The four 1000 m work reps cut down from 3:45/km to 3:42/km, with the first two at 3:45/km. Heart rate rose from 148 to 155 across the set, while the recoveries were 4:41/km, 4:56/km and 4:52/km.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 3:45 | 3:45/km | 148 | — |
| 2 | 3:45 | 3:45/km | 152 | — |
| 3 | 3:43 | 3:43/km | 154 | — |
| 4 | 3:42 | 3:42/km | 155 | — |
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).
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
Recovery32%
Z2
Endurance45%
Z3
Tempo20%
Z4
Threshold3%
Z5
VO₂max0%
Pace
Z1
Easy25%
Z2
Endurance31%
Z3
Tempo39%
Z4
Threshold5%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery0%
Z2
Endurance16%
Z3
Tempo33%
Z4
Threshold43%
Z5
VO₂max8%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+8.5%
Effort & efficiency
0.73
Running effectiveness
speed per watt/kg, reps
6.1 w/kg
Power-to-weight
rep average
2.97
Efficiency factor
norm. power per bpm
1.02
Variability index
1.0 = perfectly even power
0.7%
Rep consistency
pace spread across reps, lower is tighter
1172 kJ
Total work
mechanical energy
618 kcal
Energy
estimated burn
686 bpk
Cardiac cost
heartbeats per km
3%
Above threshold
≥ 164 bpm (Z4+)
-0:10/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace24°C · +63 m
Actual
3:44/km
Grade-adjusted
3:44/km
Heat-adjusted
3:36/km
−8s/km
True effort
3:36/km
−8s/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.