Intervalsconfidence 0.83
Frisky Frisco
Colin Dismuke50 km / marathon build
Source: own Strava export
Intervals
Frisky Frisco
Distance
18.0 km
Moving
77:17
Rep pace
3:51/km
Avg HR
160 bpm
Reps
3
Planned vs actual · TrainingPeaksPlanned 18.0 kmRan 1:17:17 · 18.0 kmIF 1.35TSS 234
Shape of the sessionEasyWorkFastest
warm up
cool down
0:003 × work / float77:17
The decode
A 3-2-1km speed progression was a controlled shift from marathon-pace work into faster efforts. The long opening blocks made restraint part of the session; the shorter close demanded speed under accumulated load.
The work accelerated from 3:59/km to 3:51/km to 3:42/km, with heart rate rising from 167 to 172 to 177. The sequence held together and finished with a 3:32/km kilometre after the 2:00 recovery.
Rep splits
| Rep | Time | Pace | HR | Float |
|---|---|---|---|---|
| 1 | 11:56 | 3:59/km | 167 | 3:00 |
| 2 | 11:34 | 3:51/km | 172 | 3:00 |
| 3 | 7:25 | 3:42/km | 177 | 2:00 |
0.83
confidence
What the engine saw
- 3 work intervals detected from lap markers, confirmed by clear pace separation.
- Recoveries average 160s.
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
Recovery22%
Z2
Endurance9%
Z3
Tempo24%
Z4
Threshold30%
Z5
VO₂max14%
Pace
Z1
Easy26%
Z2
Endurance34%
Z3
Tempo33%
Z4
Threshold6%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery1%
Z2
Endurance11%
Z3
Tempo48%
Z4
Threshold36%
Z5
VO₂max3%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+1.4%
Effort & efficiency
0.75
Running effectiveness
speed per watt/kg, reps
5.8 w/kg
Power-to-weight
rep average
2.58
Efficiency factor
norm. power per bpm
1.02
Variability index
1.0 = perfectly even power
2.9%
Rep consistency
pace spread across reps, lower is tighter
2025 kJ
Total work
mechanical energy
1243 kcal
Energy
estimated burn
745 bpk
Cardiac cost
heartbeats per km
44%
Above threshold
≥ 164 bpm (Z4+)
-0:26/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace13°C · +49 m
Actual
3:51/km
Grade-adjusted
3:51/km
Heat-adjusted
3:51/km
True effort
3:51/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.