Tempoconfidence 0.75
6km tempo
Colin Dismuke50 km / marathon build
Source: own Strava export
Tempo
6km tempo
Distance
15.4 km
Moving
63:19
Avg HR
165 bpm
Planned vs actual · TrainingPeaksPlanned 1:15:05Ran 1:03:19 · 15.4 kmIF 1.45TSS 218
Shape of the sessionEasyWorkFastest
0:00session63:19
The decode
This was a sub-threshold set: 2 × 6km with 1km easy between the sustained blocks.
The second 6km block was faster, moving from 3:54/km at 169 HR to 3:50/km at 172 HR. The effort progressed without a drop in pace.
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
Recovery10%
Z2
Endurance7%
Z3
Tempo10%
Z4
Threshold64%
Z5
VO₂max9%
Pace
Z1
Easy18%
Z2
Endurance8%
Z3
Tempo69%
Z4
Threshold5%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery1%
Z2
Endurance9%
Z3
Tempo21%
Z4
Threshold59%
Z5
VO₂max10%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR-0.1%
Effort & efficiency
0.73
Running effectiveness
speed per watt/kg, reps
5.1 w/kg
Power-to-weight
rep average
2.66
Efficiency factor
norm. power per bpm
1.02
Variability index
1.0 = perfectly even power
11.8%
Rep consistency
pace spread across reps, lower is tighter
1706 kJ
Total work
mechanical energy
1047 kcal
Energy
estimated burn
709 bpk
Cardiac cost
heartbeats per km
73%
Above threshold
≥ 164 bpm (Z4+)
-0:08/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace20°C · +35 m
Actual
4:26/km
Grade-adjusted
4:26/km
Heat-adjusted
4:21/km
−5s/km
True effort
4:21/km
−5s/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.