Intervalsconfidence 0.83
Afternoon Run
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
Afternoon Run
Distance
12.6 km
Moving
55:15
Rep pace
4:05/km
Avg HR
158 bpm
Reps
4
Planned vs actual · TrainingPeaksPlanned 1:08:00 · 14.0 kmRan 55:15 · 12.6 kmIF 1.53TSS 213
Shape of the sessionEasyWorkFastest
warm up
cool down
0:004 × work / float55:15
The decode
A descending interval ladder with one-minute recoveries was an upper-zone-2 aerobic session that progressed into tempo work. The short recoveries kept the aerobic demand continuous, while the cut-down made the final reps the point of the session rather than a separate speed block.
The effort tightened decisively: pace moved from 4:20/km and 4:14/km to 3:53/km and 3:54/km, while heart rate rose from 157 to 159 to 171 and 172. The final rep held 3:54/km after 3:53/km, so the progression stayed intact.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 12:00 | 4:20/km | 157 | 1:00 |
| 2 | 10:00 | 4:14/km | 159 | 1:00 |
| 3 | 8:00 | 3:53/km | 171 | 1:00 |
| 4 | 6:00 | 3:54/km | 172 | 1:00 |
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 60s.
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
Recovery19%
Z2
Endurance8%
Z3
Tempo37%
Z4
Threshold25%
Z5
VO₂max12%
Pace
Z1
Easy30%
Z2
Endurance43%
Z3
Tempo27%
Z4
Threshold0%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery2%
Z2
Endurance9%
Z3
Tempo42%
Z4
Threshold45%
Z5
VO₂max3%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+2.5%
Effort & efficiency
0.72
Running effectiveness
speed per watt/kg, reps
5.7 w/kg
Power-to-weight
rep average
2.63
Efficiency factor
norm. power per bpm
1.02
Variability index
1.0 = perfectly even power
4.9%
Rep consistency
pace spread across reps, lower is tighter
1351 kJ
Total work
mechanical energy
873 kcal
Energy
estimated burn
694 bpk
Cardiac cost
heartbeats per km
37%
Above threshold
≥ 164 bpm (Z4+)
-0:26/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace28°C · +19 m
Actual
4:05/km
Grade-adjusted
4:05/km
Heat-adjusted
3:53/km
−12s/km
True effort
3:53/km
−12s/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.