Intervalsconfidence 0.83
6 × 800m
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
6 × 800m
Distance
7.9 km
Moving
38:31
Rep pace
3:53/km
Avg HR
142 bpm
Reps
6
Planned vs actual · TrainingPeaksPlanned 12.0 kmRan 38:31 · 7.9 kmIF 1.32TSS 110
Shape of the sessionEasyWorkFastest
warm up
cool down
0:006 × work / float38:31
The decode
Six 800-900m reps formed an interval set with 1:30 recoveries. The fixed work duration and short recoveries made repeatability more important than a single fast repetition.
The pace sharpened to 3:43/km by rep three, then fell to 4:02/km before settling at 3:57/km and 3:58/km. Heart rate reached 160 on the final rep, the highest reading of the set, while the slower closing pace showed that the set had not held its early speed.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 3:15 | 3:51/km | 155 | 1:30 |
| 2 | 3:15 | 3:47/km | 137 | 1:30 |
| 3 | 3:15 | 3:43/km | 139 | 1:30 |
| 4 | 3:15 | 4:02/km | 141 | 1:30 |
| 5 | 3:15 | 3:57/km | 143 | 1:30 |
| 6 | 3:15 | 3:58/km | 160 | 5:48 |
0.83
confidence
What the engine saw
- 6 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 133s.
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
Recovery46%
Z2
Endurance37%
Z3
Tempo9%
Z4
Threshold8%
Z5
VO₂max0%
Pace
Z1
Easy47%
Z2
Endurance12%
Z3
Tempo35%
Z4
Threshold6%
Z5
VO₂max1%
Z6
Speed0%
Power
Z1
Recovery20%
Z2
Endurance18%
Z3
Tempo21%
Z4
Threshold32%
Z5
VO₂max10%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+7.6%
Effort & efficiency
0.73
Running effectiveness
speed per watt/kg, reps
5.9 w/kg
Power-to-weight
rep average
2.83
Efficiency factor
norm. power per bpm
1.13
Variability index
1.0 = perfectly even power
2.8%
Rep consistency
pace spread across reps, lower is tighter
826 kJ
Total work
mechanical energy
551 kcal
Energy
estimated burn
698 bpk
Cardiac cost
heartbeats per km
8%
Above threshold
≥ 164 bpm (Z4+)
+0:15/km
Split balance
positive split, slower 2nd half
Conditions-adjusted pace18°C · +19 m
Actual
3:53/km
Grade-adjusted
3:53/km
Heat-adjusted
3:50/km
−3s/km
True effort
3:50/km
−3s/km
The rep pace re-expressed for flat ground and cool air, the effort, not the clock. Adjustments are modest on this one; on a hot day or a hilly route this is where the real work hides.