Intervalsconfidence 0.83
6 × 900m
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
6 × 900m
Distance
16.0 km
Moving
70:07
Rep pace
3:49/km
Avg HR
163 bpm
Reps
6
Planned vs actual · TrainingPeaksPlanned 1:20:00Ran 1:10:07 · 16.0 kmIF 1.34TSS 209
Shape of the sessionEasyWorkFastest
warm up
cool down
0:006 × work / float70:07
The decode
Six 3:30 hard repetitions off 1:30 recoveries made this an interval session. The 30-minute low-intensity lead-in set up repeated hard running rather than one continuous effort, with the fixed recoveries keeping the demand high across the set.
The first four reps held between 3:46/km and 3:48/km before the final two moved to 3:52/km. Heart rate rose from 172 to 182 by rep five, then finished at 180, showing accumulating load without a late collapse.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 3:30 | 3:46/km | 172 | 1:30 |
| 2 | 3:30 | 3:48/km | 177 | 1:30 |
| 3 | 3:30 | 3:46/km | 179 | 1:30 |
| 4 | 3:30 | 3:47/km | 180 | 1:30 |
| 5 | 3:30 | 3:52/km | 182 | 1:30 |
| 6 | 3:30 | 3:52/km | 180 | 1:30 |
0.83
confidence
What the engine saw
- 6 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 90s.
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
Recovery8%
Z2
Endurance35%
Z3
Tempo4%
Z4
Threshold18%
Z5
VO₂max35%
Pace
Z1
Easy45%
Z2
Endurance25%
Z3
Tempo30%
Z4
Threshold0%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery1%
Z2
Endurance6%
Z3
Tempo58%
Z4
Threshold32%
Z5
VO₂max2%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+4.2%
Effort & efficiency
0.75
Running effectiveness
speed per watt/kg, reps
5.8 w/kg
Power-to-weight
rep average
2.50
Efficiency factor
norm. power per bpm
1.02
Variability index
1.0 = perfectly even power
1.1%
Rep consistency
pace spread across reps, lower is tighter
1786 kJ
Total work
mechanical energy
1157 kcal
Energy
estimated burn
755 bpk
Cardiac cost
heartbeats per km
53%
Above threshold
≥ 164 bpm (Z4+)
-0:34/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace34°C · +39 m
Actual
3:48/km
Grade-adjusted
3:48/km
Heat-adjusted
3:32/km
−16s/km
True effort
3:32/km
−16s/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.