Marathon Training Workout: 12 x 1k at 10,200' (3100 meters) - Seth James DeMoor

Aug 13, 2025

Intro: This is a quick summary of Marathon Training Workout: 12 x 1k at 10,200’ (3100 meters) 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:

The session is designed for marathon training at altitude (10,200 ft / 3,100 m) to boost anaerobic capacity.
Warm‑up and cool‑down are each about 3 mi (≈ 5 km) on mixed terrain (mostly dirt, some pavement).
Main set: 12 × 1 km repeats with roughly 90 seconds of easy jogging (or a very slow jog) between each kilometer.
Rest intervals varied between 80‑100 seconds as the watch calibrated; aim for about 90 seconds.
Heart‑rate peaked near 198 bpm on the last repeat, indicating a hard effort.
Pace ranged from ~3:05 min/km (fastest) to ~3:12 min/km (slowest) – adjust to your own threshold.

Workout Example:

Warm‑up: 3 mi (≈ 5 km) easy, include a few strides.
Main set: 12 × 1 km at ~3:05‑3:12 min/km, with 90 seconds of very slow jog or walk between each km.
Cool‑down: 3 mi (≈ 5 km) easy. Total distance ≈ 15 mi (≈ 24 km).

Practical Tips:

Use a watch or phone app to time the 90‑second recovery; a slow jog keeps legs moving.
At altitude, stay hydrated and consider a slightly slower target pace than sea‑level runs.
Pack a towel and be ready for unexpected stops (e.g., ice‑bath in a motel bathtub).

Closing Note: Give this altitude 1k repeat session a try and feel free to customize the paces and recovery in the Pacing app to match your current fitness. Running at altitude can be tough, but it’s a solid boost for marathon strength. Happy training!