Intervalsconfidence 0.83
4 × 1.1km hills
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
4 × 1.1km hills
Distance
13.5 km
Moving
60:50
Rep pace
3:42/km
Avg HR
147 bpm
Reps
4
Planned vs actual · TrainingPeaksPlanned 16.0 kmRan 1:00:50 · 13.5 kmIF 1.38TSS 191
Shape of the sessionEasyWorkFastest
warm up
cool down
0:004 × work / float60:50
The decode
This was a hill session: four repetitions of three 20-second uphill efforts with jog-down recoveries, followed by four minutes at strong half-marathon pace and two minutes easy.
The four work intervals cut down from 3:52/km to 3:40/km and 3:37/km before holding at 3:38/km. Heart rate rose from 137 to 177 across the set.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 4:02 | 3:52/km | 137 | 1:30 |
| 2 | 4:00 | 3:40/km | 139 | 1:21 |
| 3 | 4:01 | 3:37/km | 152 | 1:45 |
| 4 | 4:01 | 3:38/km | 177 | 2:01 |
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 99s.
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
Recovery43%
Z2
Endurance37%
Z3
Tempo6%
Z4
Threshold6%
Z5
VO₂max7%
Pace
Z1
Easy56%
Z2
Endurance18%
Z3
Tempo15%
Z4
Threshold9%
Z5
VO₂max1%
Z6
Speed1%
Power
Z1
Recovery5%
Z2
Endurance18%
Z3
Tempo42%
Z4
Threshold18%
Z5
VO₂max16%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+1.6%
Effort & efficiency
0.72
Running effectiveness
speed per watt/kg, reps
6.3 w/kg
Power-to-weight
rep average
2.88
Efficiency factor
norm. power per bpm
1.05
Variability index
1.0 = perfectly even power
2.7%
Rep consistency
pace spread across reps, lower is tighter
1586 kJ
Total work
mechanical energy
915 kcal
Energy
estimated burn
723 bpk
Cardiac cost
heartbeats per km
13%
Above threshold
≥ 164 bpm (Z4+)
-0:32/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace21°C · +190 m
Actual
3:41/km
Grade-adjusted
3:41/km
Heat-adjusted
3:36/km
−5s/km
True effort
3:36/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.