Threshold Run – August 1, 2025

Build Phase 2 / Week 1 / Run 3 – Road to TOWaterfront 42K

Today’s threshold run was one of those deceptive workouts: it looks simple on paper but finds a way to squeeze every drop out of you. While I hit my targets, I felt absolutely drained by the end.

I got a much later start than usual after staying up too late (again) trying to rewatch World War Z. When I woke up, I was groggy. Pre-run fueling included a white bagel with jam around 1:45 before heading out, and a Lemon-Lime SiS isotonic gel (not my favourite) washed down with Nuun.

My protocol was in play: 2 SaltStick caps before starting, then every 2 km. I also paused my watch during recovery from Stride 1 and after the second threshold interval for hydration and caps. There was another pause during the third interval at a busy intersection.

The cooler air was initially refreshing, but that didn’t last long. While the execution was mostly smooth, I was surprised at how much this run took out of me. Nutrition seemed on point, and the numbers weren’t outrageous. Still, post-run, I was zapped.

Let’s see what coach has to say.

Metrics Snapshot

Metric	Value
Duration	1:07:04
Distance	10.2 km
Avg Pace	6:36/km
Normalized Graded Pace (NGP)	6:26/km
Elevation Gain	236 m
Elevation Loss	276 m
Avg HR	153 bpm
Max HR	165 bpm
Pa:HR	4.55%
EF	1.02
Cadence Avg	167 spm
rTSS	97
hrTSS	77
VAM	211 m/h
VAM W/kg	1.08

What The Numbers Say

rTSS vs hrTSS: The rTSS of 97 and hrTSS of 77 show that pace intensity was higher than what heart rate alone would suggest – likely due to terrain or fatigue suppression.

IF (pace) vs IF (HR): 0.89 vs 0.79 also reflects this effort mismatch – your output remained high even as HR trailed slightly.

Pa:HR at 4.55% is within acceptable range for a threshold session, and EF (1.02) suggests aerobic efficiency remained solid.

VAM & VAM W/kg show that despite fatigue, you were still climbing at a strong rate (211 m/h). These numbers align with a sustainable mid-Z3 effort, especially considering the elevation gain.

Takeaways

• The cumulative fatigue is real. This run followed a progression workout and a Z2 effort earlier in the week – be mindful of the stacking.
  
• Despite being drained post-run, metrics confirm solid aerobic output.
  
• Your fueling and hydration were dialed in, though SiS gels may not be the go-to.
  
• Next time, aim for better rest the night before. Zombie flicks can wait.
  

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Still standing. Still stacking.

Check out earlier Zone 2 Run with fatigue insights

Recap, Recover, Relax & Ready.