Intervalsconfidence 0.83
6 × 800m
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
6 × 800m
Distance
12.8 km
Moving
53:59
Rep pace
3:27/km
Avg HR
162 bpm
Reps
6
Planned vs actual · TrainingPeaksPlanned 15.0 kmRan 53:59 · 12.8 kmIF 1.42TSS 181
Shape of the sessionEasyWorkFastest
warm up
cool down
0:006 × work / float53:59
The decode
Six 800m VO2 intervals used 60-second recoveries. The preceding steady effort and recovery left little room to reset, making the planned progression difficult once the opening pace ran ahead of the session’s intended shape.
The set moved from 2:36 to 2:40, 2:45, 2:49, 2:51 and 2:50; heart rate rose from 154 to 181 after the first rep, then held at 179, 179, 179 and 180. The pace did not hold, but the final two reps stayed together.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 2:36 | 3:15/km | 154 | 1:00 |
| 2 | 2:40 | 3:20/km | 181 | 1:00 |
| 3 | 2:45 | 3:26/km | 179 | 1:00 |
| 4 | 2:49 | 3:31/km | 179 | 1:00 |
| 5 | 2:51 | 3:34/km | 179 | 1:00 |
| 6 | 2:50 | 3:33/km | 180 | 1:00 |
0.83
confidence
What the engine saw
- 6 work intervals detected from lap markers, confirmed by clear pace separation.
- 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
Recovery12%
Z2
Endurance27%
Z3
Tempo15%
Z4
Threshold14%
Z5
VO₂max32%
Pace
Z1
Easy45%
Z2
Endurance14%
Z3
Tempo10%
Z4
Threshold21%
Z5
VO₂max8%
Z6
Speed2%
Power
Z1
Recovery0%
Z2
Endurance18%
Z3
Tempo36%
Z4
Threshold31%
Z5
VO₂max11%
Z6
Anaerobic3%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+3.5%
Effort & efficiency
0.76
Running effectiveness
speed per watt/kg, reps
6.4 w/kg
Power-to-weight
rep average
2.67
Efficiency factor
norm. power per bpm
1.04
Variability index
1.0 = perfectly even power
3.4%
Rep consistency
pace spread across reps, lower is tighter
1431 kJ
Total work
mechanical energy
889 kcal
Energy
estimated burn
724 bpk
Cardiac cost
heartbeats per km
46%
Above threshold
≥ 164 bpm (Z4+)
-0:25/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace25°C · +73 m
Actual
3:26/km
Grade-adjusted
3:26/km
Heat-adjusted
3:18/km
−8s/km
True effort
3:18/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.