Tempoconfidence 0.75
2km tempo
Colin Dismuke50 km / marathon build
Source: own Strava export
Tempo
2km tempo
Distance
16.1 km
Moving
78:41
Avg HR
146 bpm
Planned vs actual · TrainingPeaksPlanned 20.0 kmRan 1:18:41 · 16.1 kmIF 1.23TSS 199
Shape of the sessionEasyWorkFastest
0:00session78:41
The decode
A tempo session built around two 8-minute blocks and a 3-minute finish. The 3-minute easy recoveries separated the sustained work without changing the session's elevated-effort character, while the shorter final block demanded a sharper close.
The work accelerated from 3:58/km to 3:52/km to 3:33/km as heart rate rose from 165 to 170 to 171. Heart rate fell to 148 and 147 during the recoveries, but the final block still reached 171.
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
Recovery49%
Z2
Endurance29%
Z3
Tempo5%
Z4
Threshold15%
Z5
VO₂max3%
Pace
Z1
Easy79%
Z2
Endurance2%
Z3
Tempo17%
Z4
Threshold2%
Z5
VO₂max0%
Z6
Speed0%
Power
Z1
Recovery3%
Z2
Endurance39%
Z3
Tempo42%
Z4
Threshold12%
Z5
VO₂max4%
Z6
Anaerobic0%
Z7
Neuro0%
Aerobic decoupling · Pa:HR+3.4%
Effort & efficiency
0.74
Running effectiveness
speed per watt/kg, reps
4.7 w/kg
Power-to-weight
rep average
2.58
Efficiency factor
norm. power per bpm
1.05
Variability index
1.0 = perfectly even power
23.3%
Rep consistency
pace spread across reps, lower is tighter
1990 kJ
Total work
mechanical energy
1141 kcal
Energy
estimated burn
831 bpk
Cardiac cost
heartbeats per km
18%
Above threshold
≥ 164 bpm (Z4+)
-0:23/km
Split balance
negative split, faster 2nd half
Conditions-adjusted pace25°C · +20 m
Actual
4:45/km
Grade-adjusted
4:45/km
Heat-adjusted
4:34/km
−11s/km
True effort
4:34/km
−11s/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.