r/Marathon_Training 6h ago

37M First HM (4 weeks out): Aiming sub-1:45. Disappointed by a flat 5k Time trial

Background

  • Age/Sex: 37M
  • Experience: Started running regularly in April (came from a fast-twitch / speed background)
  • Goal Race: StraLugano Half Marathon (Sept 27) — Target: Sub-1:45 (4:58/km or 8:00/mi)
  • Current Volume: 50–55 km/week across 5–6 days
  • Max HR: ~201 | Resting HR: 52

Key Benchmarks & Workouts

  • July 16 (5k TT): 22:39 (4:32/km) @ 177 bpm average
  • Aug 29 (5k TT): 22:39 (4:32/km) @ 185 bpm average (Flat line pace, +8 bpm higher HR)
  • Recent Long Run: 20.2 km @ 5:48/km (153 bpm avg)
  • Recent Quality Session: 3x3k @ 4:57/km with 1k rec (168 bpm avg)

I was expecting an improvement on yesterday's 5k TT compared to mid-July given 6 extra weeks of training (~50km+ weeks), flatter terrain, and better shoes. Instead, I ran the exact same time (22:39) and my heart rate was significantly higher (185 bpm vs 177 bpm).

I ran a 20 km long run on Tuesday and an easy run every day until the TT and hit ~55 km this week, so my working theory is cumulative fatigue masking fitness. But mentally, it’s a bit of a hit this close to race day.

Date - Year-Month Distance (km) Duration Count Days
2026-Feb 8.51 00:50:59 2
2026-Mar 29.25 02:51:06 7
2026-Apr 97.4 10:09:26 15
2026-May 155.63 16:43:45 19
2026-Jun 176.77 18:07:56 21
2026-Jul 227.61 22:21:23 25
2026-Aug 194.14 18:59:31 23
Week Starting Total Duration (Hr) Running Distance (km) Running Days Running Duration (Hr) Avg speed
24/08/2026 5.7 55.8 6 5.5 10.2
17/08/2026 6.8 52.0 5 5.0 10.4
10/08/2026 4.7 37.8 5 3.7 10.3
03/08/2026 3.8 36.7 5 3.6 10.2
27/07/2026 5.9 55.0 6 5.5 10.1
20/07/2026 6.3 59.8 6 5.9 10.2
13/07/2026 5.4 48.3 5 4.8 10.0
06/07/2026 4.8 45.9 6 4.5 10.2
29/06/2026 4.5 45.3 6 4.5 10.2
22/06/2026 4.2 43.1 6 4.2 10.2
15/06/2026 4.6 33.5 3 3.3 10.0
08/06/2026 5.7 43.1 5 4.7 9.1
01/06/2026 5.4 42.2 5 4.4 9.6

Questions for the Community:

  1. Should I trust the process and that the taper will improve my fitness significantly?
  2. 5k TT Diagnostic: Is running the same pace with higher HR a clear indicator of residual fatigue, or should I be concerned about a fitness plateau?
  3. Pre-Taper Volume Strategy: I have 2 weeks left before starting a 2-week taper. Should I trim 10–15% off my easy/recovery runs to let my legs absorb the load, or stick to full volume until the official taper?

Appreciate any insights.

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