Intervalsconfidence 0.83
7 × 800m
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
7 × 800m
Distance
9.5 km
Moving
43:30
Rep pace
3:36/km
Avg HR
163 bpm
Reps
7
Shape of the sessionEasyWorkFastest
warm up
cool down
0:007 × work / float43:30
The decode
The session was a seven-repetition 800m interval set with 60s recoveries, completed in 32 C heat.
The first two reps were 3:21/km and 3:25/km, followed by 3:33/km for reps three and four before slowing to 3:49/km, 3:41/km and 3:50/km. Rep heart rate stayed between 172 and 178, peaking at 178 on the fourth rep.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 2:41 | 3:21/km | 172 | 1:00 |
| 2 | 2:44 | 3:25/km | 175 | 1:00 |
| 3 | 2:51 | 3:33/km | 174 | 1:00 |
| 4 | 2:50 | 3:33/km | 178 | 1:00 |
| 5 | 3:03 | 3:49/km | 174 | 1:00 |
| 6 | 2:57 | 3:41/km | 176 | 1:00 |
| 7 | 3:04 | 3:50/km | 175 | 1:00 |
0.83
confidence
What the engine saw
- 7 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
Endurance29%
Z3
Tempo12%
Z4
Threshold11%
Z5
VO₂max36%
Pace
Z1
Easy49%
Z2
Endurance9%
Z3
Tempo14%
Z4
Threshold16%
Z5
VO₂max10%
Z6
Speed1%
Power
Z1
Recovery16%
Z2
Endurance20%
Z3
Tempo20%
Z4
Threshold28%
Z5
VO₂max15%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+9.2%
Effort & efficiency
0.74
Running effectiveness
speed per watt/kg, reps
6.2 w/kg
Power-to-weight
rep average
2.56
Efficiency factor
norm. power per bpm
1.11
Variability index
1.0 = perfectly even power
4.8%
Rep consistency
pace spread across reps, lower is tighter
1066 kJ
Total work
mechanical energy
678 kcal
Energy
estimated burn
831 bpk
Cardiac cost
heartbeats per km
47%
Above threshold
≥ 164 bpm (Z4+)
+0:19/km
Split balance
positive split, slower 2nd half
Conditions-adjusted pace32°C · +22 m
Actual
3:35/km
Grade-adjusted
3:35/km
Heat-adjusted
3:22/km
−13s/km
True effort
3:22/km
−13s/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.