Intervalsconfidence 0.83
5 × 400m
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
5 × 400m
Distance
7.7 km
Moving
36:24
Rep pace
3:25/km
Avg HR
152 bpm
Reps
5
Shape of the sessionEasyWorkFastest
warm up
cool down
0:005 × work / float36:24
The decode
The session was an interval set of five 400m reps with 60s recoveries.
The reps ran in 1:24, 1:22, 1:26, 1:22 and 1:16, with the final rep the fastest at 3:10/km. Heart rate was 156, 159, 162, 152 and 160.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 1:24 | 3:30/km | 156 | 1:00 |
| 2 | 1:22 | 3:25/km | 159 | 1:00 |
| 3 | 1:26 | 3:34/km | 162 | 1:00 |
| 4 | 1:22 | 3:24/km | 152 | 1:00 |
| 5 | 1:16 | 3:10/km | 160 | 1:00 |
0.83
confidence
What the engine saw
- 5 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
Recovery36%
Z2
Endurance15%
Z3
Tempo16%
Z4
Threshold24%
Z5
VO₂max9%
Pace
Z1
Easy54%
Z2
Endurance2%
Z3
Tempo11%
Z4
Threshold14%
Z5
VO₂max14%
Z6
Speed5%
Power
Z1
Recovery21%
Z2
Endurance26%
Z3
Tempo3%
Z4
Threshold26%
Z5
VO₂max23%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+8%
Effort & efficiency
0.79
Running effectiveness
speed per watt/kg, reps
6.2 w/kg
Power-to-weight
rep average
2.77
Efficiency factor
norm. power per bpm
1.13
Variability index
1.0 = perfectly even power
4.0%
Rep consistency
pace spread across reps, lower is tighter
841 kJ
Total work
mechanical energy
543 kcal
Energy
estimated burn
759 bpk
Cardiac cost
heartbeats per km
32%
Above threshold
≥ 164 bpm (Z4+)
+0:10/km
Split balance
positive split, slower 2nd half
Conditions-adjusted pace20°C · +30 m
Actual
3:24/km
Grade-adjusted
3:24/km
Heat-adjusted
3:20/km
−4s/km
True effort
3:20/km
−4s/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.