Marathon Training Plan Design Day - Seth James DeMoor

Aug 13, 2025

Intro

This is a quick summary of Marathon Training Plan Design Day from Seth James DeMoor. It’s a great watch — we’re breaking it down so you can try the workout today. Be sure to check out the full video for all the details.

Key Points

Register the race first; the commitment makes the whole plan feel real.
Treat the training block like building a house: foundation (first 2‑4 weeks), framing (weekly mileage), and finishing touches (speed work, tune‑up race, taper).
The block is 16 weeks long, launching on Dec 20 and culminating with the Rotterdam Marathon on April 10.
Weekly volume ramps from 60 mi in week 1 to ≈105 mi by week 4, then gradually tapers after a tune‑up race around week 7.
Shift focus after the tune‑up: lower volume, higher quality (VO₂‑max intervals, threshold runs, and longer hard‑pace long runs of 22‑24 mi).
Aim to hit a hard‑pace long run at least three times in the block to build confidence for marathon‑pace effort.

Workout Example

Week 1 (Launch Week – 60 mi total)

Monday: Easy 5 mi + mobility/foam‑rolling
Tuesday: VO₂‑max interval session – 5 × 800 m @ 5K pace with 2 min jog recoveries (≈4 mi total)
Wednesday: Easy 6 mi
Thursday: Tempo run – 2 mi easy, 4 mi at threshold (≈10 mi total)
Friday: Rest or cross‑train (strength/hip work)
Saturday: Long run – 12 mi at comfortable pace, finish last 2 mi at marathon‑goal pace
Sunday: Recovery 5 mi easy

Progression: Increase weekly mileage by ~10‑15 mi each week until hitting ~105 mi by week 4, then start the taper after the tune‑up race (week 7) by cutting volume ~20‑30 % while keeping intensity (VO₂‑max & threshold) sharp.

Closing Note

Give this marathon block a try—customise the paces to your own numbers in the Pacing app and adjust mileage to fit your schedule. Register your race, plot the mileage “roller‑coaster,” and watch your confidence grow. Happy training, and see you at the finish line!