My Road to TOWaterfront 42K
This session was structured as a progression run, moving step by step through Zones 2–4. The aim: practice control at the bottom end, then gradually layer effort until the wheels threaten to come off.
Another late start! I woke up feeling like an anvil lay on top of me in bed, so no early morning run. I hoped that I would still get the workout in, albeit later in the day.
I had a beef cheeseburger for lunch, around 11:30, then 2 slices of white bread and 2 tablespoons of jam around 2 pm, just in case I would get to run around 4pm. I began sipping on my Maurten Mix 160 about 45 mins to 1 hour before blast-off.
I set off after a brief dynamic warmup. I probably should have spent more time getting my blood flowing a little longer, but I was impatient to tackle the progression. I had set up my Drum Buddy playlist to keep me locked in (164/166/168/169/170/172 bpm). The beats helped as usual, judging by the Lap Ladder (check it out). I progressed my pace steadily through each 10-minute block until my legs couldn’t handle it any longer. I don’t think it was a fueling issue – I did ingest a Gel 160 at about 18–20 minutes in. I think it was fatigue carried over from yesterday’s “Easy Run” – those ascents took more of a toll than I realized.
I’m still bummed that I was only able to complete 45 minutes of a scheduled 1 hr 5 minute workout.
Key Metrics
- Duration: 45:17 (planned 1:05:00)
- Distance: 6.9 km
- Avg Pace: 6:34/km (NGP: 6:28/km)
- rTSS / IF (pace): 65 / 0.79
- hrTSS / IF (HR): 52 / 0.78
- Avg HR / Max HR: 153 / 167 bpm
- Elevation Gain / Loss: 112 m / 107 m
- Pa:HR: 7.43%
- Cadence Avg / Max: 165 / 237 spm (sensor spike on max)
- Calories: 494 kcal
- Weather (16:09): 22°C (feels 21), 44% humidity, DP 5.9°C, wind 11.4 km/h W
Lap Check
- Early Laps: Settled in quickly at ~6:45–6:30/km, HR rising steadily but under control.
- Lap 5: Marked a shift – pace dropped to 6:18/km with HR climbing to 157–161. Solid block execution.
- Later Laps: Cadence held steady (164–167 spm), but stride length shortened as fatigue crept in.
- End Cut Short: The workout terminated after 45 minutes, leaving Z4 blocks incomplete. The metrics file confirms rising strain but no erratic drift – fatigue, not fueling, ended the session.
What Your Numbers Say
- rTSS 65 vs hrTSS 52 → Legs flagged this as harder than your heart did. Mechanical fatigue, not aerobic failure, pulled the plug.
- IF (pace 0.79 vs HR 0.78) → Both measures agree this was controlled – no sign of overcooking.
- Pa:HR 7.43% → Safely inside the 10% range, meaning you stayed efficient even toward the end.
- Cadence 165 spm → Rock steady, proving the Drum Buddy progression kept you in rhythm. Stride length, not cadence, gave way.
- NGP 6:28/km vs Actual 6:34/km → Terrain explains the gap; normalized pace shows you were on the right track.
👉 Translation: Aerobic system fine, rhythm strong, but the legs had the final say.
Coach’s Corner
This was a reminder that not every limiter is cardiovascular. Yesterday’s “easy” run with ascents clearly put more load on your quads than expected. By the time you reached mid-Z3, the mechanical fatigue surfaced and dictated the stop. That’s not a failure – it’s part of the build.
From a coaching lens:
- Training impact: You still banked 45 minutes of structured, progressive aerobic work. That stimulus matters.
- Lesson learned: Watch cumulative leg load from consecutive climbing runs. Even when RPE feels fine, the muscles may still be carrying hidden debt.
- Forward takeaway: Don’t discount short progression runs. They reveal “mechanical ceilings” that heart-rate-only monitoring misses – and catching that is a win.
👉 Bigger picture: This was a strategic deposit, even if it didn’t hit the full 65 minutes. In marathon prep, knowing when fatigue is muscular vs fueling is a critical skill.
Conclusion
A progression run that ended early but still delivered 45 solid minutes of structured effort. Rhythm was locked in, aerobic stability was clear, but legs had other ideas. Sometimes fatigue from the day before wins – the value here is recognizing when it’s muscular load, not fueling or heart rate, that dictates the stop.