Tempoconfidence 0.75
4.1km tempo
Colin Dismuke50 km / marathon build
Source: own Strava export
Tempo
4.1km tempo
Distance
12.3 km
Moving
49:55
Avg HR
154 bpm
Planned vs actual · TrainingPeaksPlanned 1:10:45 · 16.3 kmRan 49:55 · 12.3 kmIF 1.66TSS 226
Shape of the sessionEasyWorkFastest
0:00session49:55
The decode
A 15'+10'+5' threshold set was built around sustained blocks rather than repetition speed. The easy floats kept the effort continuous, while the late headwind added resistance to the closing work.
Pace moved from 3:41/km to 3:42/km to 3:34/km, so the set finished faster rather than fading. Heart rate rose from 153 to 174, then remained high at 170 for the final block.
0.75
confidence
What the engine saw
- A sustained elevated-effort block with controlled pace variation.
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
Recovery20%
Z2
Endurance31%
Z3
Tempo19%
Z4
Threshold12%
Z5
VO₂max18%
Pace
Z1
Easy32%
Z2
Endurance10%
Z3
Tempo31%
Z4
Threshold27%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery1%
Z2
Endurance13%
Z3
Tempo28%
Z4
Threshold32%
Z5
VO₂max24%
Z6
Anaerobic1%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+14%
Effort & efficiency
0.71
Running effectiveness
speed per watt/kg, reps
5.5 w/kg
Power-to-weight
rep average
2.92
Efficiency factor
norm. power per bpm
1.03
Variability index
1.0 = perfectly even power
14.3%
Rep consistency
pace spread across reps, lower is tighter
1348 kJ
Total work
mechanical energy
804 kcal
Energy
estimated burn
648 bpk
Cardiac cost
heartbeats per km
30%
Above threshold
≥ 164 bpm (Z4+)
+0:00/km
Split balance
even split
Conditions-adjusted pace29°C · +46 m
Actual
4:15/km
Grade-adjusted
4:15/km
Heat-adjusted
4:02/km
−13s/km
True effort
4:02/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.