Marathon Prep: 12-Week Foundation
Build the engine to finish 42 km - strong, not surviving.
Adds the plan to My Library so you can check off each day as you train.
Goal
Complete a strong marathon
Duration
12 Weeks
Frequency
5 days/wk
Level
Intermediate
Full program
Premium$9.99 / month
All Access subscription — unlocks every program and meal plan. Cancel anytime.
- 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
Prefer to buy once? Get lifetime 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
Weekly schedule
Your 7-day training split
Tap to see which day trains what
Weekly schedule
Your 7-day training split
Tap to see which day trains what
- MondayStrength for Runners
- TuesdayIntervals
- WednesdayEasy Run
- ThursdayTempo Run
- FridayRest · optional 20–30 min walk or light mobility
- SaturdayLong Run
- SundayRecovery Run / Walk · keep it easy (Zone 1, nasal-breath pace)
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
Prep tips for the week
Win the day before you step in the gym
8 quick habits that make every session count
Prep tips for the week
Win the day before you step in the gym
8 quick habits that make every session count
Shaker, belt, straps, sleeves, headphones. Zero friction in the morning = zero excuses.
Slow carb + lean protein (oats + whey, rice + chicken). Fuels heavy work without sitting heavy in the stomach.
500 ml water + a pinch of salt 30 min before training. Cramping and brain-fog usually = dehydration, not weakness.
Run the full 3-stage protocol above. Skipping it is the fastest way to leave 10% on the platform.
Weight, reps, RPE. If you don't track it, you can't progress it. Use the Onyx app or a notebook, just log.
Set the rest column as a timer on your watch. Drifting past rest kills intensity and stretches sessions 2x.
0.4 g/kg bodyweight. Whey + banana works, real meal works better. Recovery starts here.
Every 4–6 weeks drop volume 40%. Strength is built in recovery, not in extra sets.
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
Intervals
VO2 max · 800 m repeats
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Warm-Up Jog (Zone 2) | 1 | 10 min easy | - |
| Treadmill Run (Zone 5) | 6 | 800 m @ 5K pace | 2 min jog |
| Cool-Down Jog | 1 | 10 min easy | - |
Week 1 · Day 3
Easy Run
Zone 2 aerobic base
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Treadmill Run (Zone 2, conversational) | 1 | 40–50 min | - |
Week 1 · Day 4
Tempo Run
Lactate threshold · comfortably hard
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Warm-Up Jog | 1 | 10 min easy | - |
| Treadmill Run (Zone 4) | 1 | 25–35 min at threshold pace | - |
| Cool-Down Jog | 1 | 10 min easy | - |
Week 1 · Day 5
Long Run
Endurance build · adds 1–2 km per week
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Treadmill Run (Zone 2) | 1 | 90–150 min at conversational pace | - |
| Treadmill Walk (cool-down) | 1 | 5–10 min flat | - |
Week 1 · Day 6
Recovery Run / Walk
Blood flow · nothing hard
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Treadmill Walk or Very Easy Run | 1 | 20–30 min at Zone 1 | - |
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 | — |
Reviews & Ratings
What athletes are saying
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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.