Intervalsconfidence 0.83
5 × 1km
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
5 × 1km
Distance
15.8 km
Moving
67:54
Rep pace
3:42/km
Avg HR
156 bpm
Reps
5
Planned vs actual · TrainingPeaksPlanned 59:38 · 14.0 kmRan 1:07:54 · 15.8 kmIF 1.37TSS 212
Shape of the sessionEasyWorkFastest
warm up
cool down
0:005 × work / float67:54
The decode
A 3km marathon-pace segment followed by five 1km threshold reps was a progressive mixed set. The 200m floats kept the work continuous rather than fully resetting it, while the headwind raised the cost of holding threshold effort.
The reps held together from 3:47/km on the third to 3:38/km on the last, with 3:40/km repeated twice. Heart rate rose from 165 on the opening rep to 181 on the second, then stayed at 179-180 through the remaining work.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 3:43 | 3:43/km | 165 | 0:55 |
| 2 | 3:40 | 3:40/km | 181 | 0:58 |
| 3 | 3:47 | 3:47/km | 179 | 0:58 |
| 4 | 3:40 | 3:40/km | 179 | 0:59 |
| 5 | 3:38 | 3:38/km | 180 | 0:58 |
0.83
confidence
What the engine saw
- 5 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 57s.
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
Endurance27%
Z3
Tempo11%
Z4
Threshold18%
Z5
VO₂max23%
Pace
Z1
Easy36%
Z2
Endurance35%
Z3
Tempo19%
Z4
Threshold9%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery0%
Z2
Endurance15%
Z3
Tempo46%
Z4
Threshold29%
Z5
VO₂max8%
Z6
Anaerobic1%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+10.3%
Effort & efficiency
0.74
Running effectiveness
speed per watt/kg, reps
6.1 w/kg
Power-to-weight
rep average
2.71
Efficiency factor
norm. power per bpm
1.03
Variability index
1.0 = perfectly even power
1.3%
Rep consistency
pace spread across reps, lower is tighter
1842 kJ
Total work
mechanical energy
1078 kcal
Energy
estimated burn
743 bpk
Cardiac cost
heartbeats per km
41%
Above threshold
≥ 164 bpm (Z4+)
+0:00/km
Split balance
even split
Conditions-adjusted pace20°C · +55 m
Actual
3:42/km
Grade-adjusted
3:42/km
Heat-adjusted
3:37/km
−5s/km
True effort
3:37/km
−5s/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.