Marathon Prep: 12-Week Foundation
Build the engine to finish 42 km - strong, not surviving.
Goal
Complete a strong marathon
Duration
12 Weeks
Frequency
5 days/wk
Level
Intermediate
Full program
Premium$9.99 · one-time
Lifetime access inside the Onyx app.
- 12 Weeks of programming
- 5× sessions per week
- Every exercise wired to a video walkthrough
- Nutrition, supplementation & recovery guide
- Lifetime updates inside the Onyx app
Want everything? Get All Access for $79
Workout Summary
Marathon Prep: 12-Week Foundation
Five running days plus two short strength sessions. Long runs build to 32 km, with weekly tempo and interval work to lift threshold pace.
Who it's for
- Lifters who want a clear plan with zero guesswork
- Athletes returning from a layoff or chasing a new PR
- Anyone tired of stitching together random YouTube workouts
What you get
- Full week-by-week progression
- Every session with sets, reps and rest
- Substitutions from the Onyx exercise library
- Nutrition, supplementation and recovery guidance
Pre-session protocol
Warm-up · do this before every workout
Nutrition
Nutrition · Endurance
Hit a daily protein target of 0.8–1 g per pound of bodyweight, anchor meals around whole-food carbs, and stay within ±300 kcal of the goal (surplus, maintenance or deficit) for the duration of the block.
Supplementation
Supplementation
Creatine monohydrate (5 g/day), a quality whey or plant protein to backfill daily protein, electrolytes around training, and vitamin D3 + magnesium for recovery.
Sleep & Recovery
Sleep & Recovery
Sleep 7–9 hours, walk 8–10k steps/day, protect one true rest day, and reduce intensity any week sleep or stress fall off a cliff.
Training Overview
Training Overview
Sessions pair the highest-return compound from the Onyx library with focused accessory work. Volume rises in waves and deloads on schedule so nothing breaks down.
12 Weeks · Progression
Progression
Weeks 1–2 build technique and baseline loads. Mid-block (weeks 3–5) progressively overload top sets. Final weeks intensify, then deload + retest in the closing week.
Weekly Schedule
Weekly Schedule
Heart rate zones
How to read your zones
Every endurance session is built around heart-rate zones so you train the right system on the right day. Use a watch, chest strap, or the talk-test to stay in the target band.
Tip: Estimate your max heart rate with 220 minus your age, then match the percentages above. Adjust by feel - the talk-test never lies.
Workouts
Marathon Prep: 12-Week Foundation
Week 1 free preview · Weeks 2–12 unlock after purchase
Week 1 · Day 1
Strength for Runners
Single-leg
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Goblet Squat | 3 | 8 | 90 sec |
| Romanian Deadlift | 3 | 8 | 90 sec |
| Walking Lunge | 3 | 12/side | 60 sec |
| Standing Calf Raise | 4 | 15 | 45 sec |
Week 1 · Day 2
Optional · Active recoveryZone-2 Walk
Easy 30–40 min walk — outdoor or treadmill. Conversational pace, builds aerobic base and speeds recovery.
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Treadmill Walking | 1 | 30–40 min | — |
| Treadmill Incline Walking | Optional finisher | 2 × 5 min @ 6% incline | 2 min |
Week 1 · Day 3
Intervals
VO2 max
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Treadmill Run (Zone 5) | 6 | 800 m | 2 min jog |
Week 1 · Day 4
Optional · Active recoveryBike + Mobility
Light spin to flush the legs, then core and mobility to protect the joints for tomorrow's lift.
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Stationary Cycle | 1 | 25–30 min easy | — |
| Plank | 3 | 30 sec | 45 sec |
| Hanging Leg Raise | 3 | 10 | 60 sec |
Week 1 · Day 5
Long Run
Endurance build
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Treadmill Run (Zone 2) | 1 | 90–150 min | - |
Week 1 · Day 6
Optional · Active recoveryRow + Core
Low-intensity rowing intervals + core stability. Keeps you moving without taxing the nervous system.
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Rowing Machine | 5 | 3 min easy / 1 min rest | 1 min |
| Side Plank | 3 | 30 sec/side | 45 sec |
| Bicycle Crunches Easy | 3 | 20 | 45 sec |
Week 1 · Day 7
Optional · Active recoveryFull Rest or Light Walk
Take the day off, or just walk 20–30 min and stretch. Recovery is when the gains happen.
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Treadmill Walking | Optional | 20–30 min easy | — |
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FAQ
FAQ
Can I move sessions around to fit my schedule?
Yes - keep the order of training days but swap which calendar day they land on. Avoid stacking the two hardest sessions back-to-back.
What if I miss a workout?
Slide the week back by one day rather than doubling up. Recovery is the variable that creates progress.
Run this in the Onyx app
Track every set. Auto-progress every week.
This program is built right into Onyx - videos, logging, deload triggers and PR alerts.