Intervalsconfidence 0.83
10 × 400m
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
10 × 400m
Distance
17.6 km
Moving
86:17
Rep pace
3:34/km
Avg HR
157 bpm
Reps
10
Shape of the sessionEasyWorkFastest
warm up
cool down
0:0010 × work / float86:17
The decode
Ten 400m reps followed by a 2km effort made this a speed-endurance set. The one-minute recoveries kept the work dense, and the closing effort extended the demand after the final rep.
The reps ranged from 3:25/km to 3:44/km without a late collapse. Heart rate was variable early, then reached 163 on the final rep; the closing 2km at 3:46/km lifted it to 177.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 1:30 | 3:44/km | 157 | 1:00 |
| 2 | 1:25 | 3:32/km | 139 | 1:00 |
| 3 | 1:29 | 3:43/km | 142 | 1:00 |
| 4 | 1:22 | 3:25/km | 140 | 1:00 |
| 5 | 1:25 | 3:32/km | 148 | 1:00 |
| 6 | 1:26 | 3:35/km | 159 | 1:00 |
| 7 | 1:26 | 3:35/km | 153 | 1:00 |
| 8 | 1:23 | 3:28/km | 162 | 1:00 |
| 9 | 1:24 | 3:31/km | 161 | 1:00 |
| 10 | 1:24 | 3:30/km | 163 | 1:00 |
0.83
confidence
What the engine saw
- 10 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
Recovery11%
Z2
Endurance28%
Z3
Tempo22%
Z4
Threshold30%
Z5
VO₂max9%
Pace
Z1
Easy49%
Z2
Endurance29%
Z3
Tempo8%
Z4
Threshold12%
Z5
VO₂max3%
Z6
Speed0%
Power
Z1
Recovery13%
Z2
Endurance13%
Z3
Tempo37%
Z4
Threshold24%
Z5
VO₂max12%
Z6
Anaerobic1%
Z7
Neuro0%
Aerobic decoupling · Pa:HR-0.9%
Effort & efficiency
0.77
Running effectiveness
speed per watt/kg, reps
6.1 w/kg
Power-to-weight
rep average
2.66
Efficiency factor
norm. power per bpm
1.10
Variability index
1.0 = perfectly even power
2.7%
Rep consistency
pace spread across reps, lower is tighter
2199 kJ
Total work
mechanical energy
1270 kcal
Energy
estimated burn
870 bpk
Cardiac cost
heartbeats per km
39%
Above threshold
≥ 164 bpm (Z4+)
-0:02/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace23°C · +203 m
Actual
3:33/km
Grade-adjusted
3:33/km
Heat-adjusted
3:27/km
−6s/km
True effort
3:27/km
−6s/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.