Marathon Sub-3:45 Training Plan
The Marathon Sub-3:45 plan is a 16-week intermediate program designed by Ilya Tyapkin, a professional runner and Rio 2016 Olympic marathon representative.
As the plan states, the plan gradually builds mileage, alternating between easy runs, intervals, fartlek, tempo sessions, and long runs to develop endurance, speed, and race-pace control. Recovery weeks are included every 4th week to let your body adapt.
Who This Plan Is For
This plan is designed for intermediate runners who have a solid running base and are ready to commit to structured marathon training. You are ready for it if your current marathon time is between 3:45 and 4:15, or you have a recent half-marathon between 1:45 and 2:00, you are comfortably running 40 to 50 kilometers per week, and you have experience with interval training and long runs of 20 kilometers or more.
If you are running your first marathon or your longest recent run is below 15 kilometers, a beginner marathon program is the more appropriate starting point. This plan begins at 57 km in Week 1 and peaks at 99 km in Week 11, with long runs reaching 35 km volumes that require a well-established aerobic base to handle without breakdown or injury.
What Makes This Plan Different
The sub-3:45 marathon is fundamentally different from shorter race targets because the primary challenge is not speed it is sustained endurance at a controlled pace for nearly four hours. Interval paces of 4:15–4:25 per kilometer for 400m reps and 4:40–4:50 per kilometer for 1km and 2km reps are run significantly faster than race pace, building the aerobic ceiling that makes 5:20 per kilometer feel manageable deep into the race. The fartlek sessions are unstructured, alternating fast and slow efforts, which develop the aerobic efficiency and mental resilience that structured interval work alone cannot replicate.
The critical insight built into this plan is that sub-3:45 is a fatigue-management problem. Most runners at this level can run 5:20 per kilometer for 20 kilometers without difficulty. The challenge is holding that pace at kilometer 32 when glycogen stores are depleting, and muscular fatigue is compounding. The progressive long runs with active sections at 5:15–5:30 per kilometer built into the middle of the run in Weeks 9, 10, and 11 are the most important sessions in the entire plan. They teach your body to run strongly even after fatigue sets in.
As Ilya notes for Week 11, the biggest week of your training cycle. Long intervals, tough tempo, and the 35 km long run mark the peak of your marathon preparation. This is where you gain the confidence and endurance needed for 42.2 km.
Plan Structure: 16 Weeks, 5 Phases
Weeks 1–3 — Base: 400m intervals build speed and leg turnover. Tempo runs develop lactate threshold. Long runs are done on hills to build strength endurance. Volume builds each week.
Week 4 — Recovery: Easy running only. A full reset after the opening block.
Weeks 5–7 — Build: Intervals grow to 1km repeats. Fartlek sessions replace tempo runs on Fridays, teaching effort modulation across changing paces. Long runs extend significantly each week.
Week 8 — Recovery: Easy running only. A second reset before the hardest training block.
Weeks 9–11 — Peak: Intervals shift to 2km repeats. Tempo runs extend to their longest distances. Long runs become structured — easy opening, active middle section at close to race pace, easy closing. Week 11 is the biggest and hardest week of the plan.
Week 12 — Recovery: Easy running only. Training adaptations consolidate this week.
Weeks 13–14 — Sharpen: Intervals and tempo runs return at slightly reduced volume. Long runs remain substantial. The focus shifts from building fitness to maintaining and honing it.
Week 15 — Taper: Volume drops sharply. Short, light intervals keep legs sharp. Rest and recovery take priority.
Week 16 — Race Week: Two short easy runs, light strides on Saturday, race day Sunday.
Sample Training Week
Week 11 is the most demanding week in the plan and the clearest representation of what sub-3:45 marathon training requires at its peak.
| Day | Session | Load |
|---|---|---|
| Monday | 12 km easy run (low heart rate) | Medium |
| Tuesday | 3 km WU + RD / Intervals: 8×2km with 400m jog recovery at 4:45–4:55/km / 3 km CD | High |
| Wednesday | Rest | — |
| Thursday | 12 km easy run (low heart rate) | Medium |
| Friday | 3 km WU + RD / 12 km tempo at 5:00–5:10/km / 3 km CD | High |
| Saturday | Rest | — |
| Sunday | Long run 35 km: 10 km easy + 15 km active @ 5:15–5:30/km + 10 km easy | High |
Total volume this week: approximately 99 kilometers, including 16 km of 2km intervals, 12 km tempo, and a 35 km structured long run.
The 35 km structured long run is the most important single session in the entire 16-week plan. Running 15 km at 5:15–5:30 per kilometer, just faster than race pace, after 10 km of easy running places you in a state of pre-existing fatigue before the active section even begins. Completing it with controlled form and even pacing is not just a fitness test; it is a direct simulation of what kilometers 25 through 38 of your marathon will demand.
Pace Guide
| Session Type | Pace (min/km) | Pace (min/mile) |
|---|---|---|
| Easy / Low HR Run | 5:40–6:10 | 9:07–9:55 |
| Intervals 400m | 4:15–4:25 | 6:50–7:07 |
| Intervals 1km | 4:40–4:50 | 7:31–7:47 |
| Intervals 2km | 4:45–4:55 | 7:39–7:55 |
| Tempo | 5:00–5:10 | 8:03–8:19 |
| Race Pace (Goal) | 5:20 | 8:35 |
One notable feature of this pace chart is the progression of interval distances from 400m at 4:15–4:25 per kilometer in the Base phase, to 1km at 4:40–4:50 in the Build phase, to 2km at 4:45–4:55 in the Peak phase. Each progression shifts the stimulus from pure neuromuscular speed toward sustained aerobic efficiency at marathon-relevant durations. The tempo pace of 5:00–5:10 per kilometer sits 10 to 20 seconds per kilometer faster than race pace training your lactate threshold to sit comfortably above 5:20 so that race pace feels controlled throughout the first 30 km.
The Long Run Progression
The long run is the defining session of any marathon training plan, and in this plan, its progression is the most carefully engineered element of the entire 16 weeks. Long runs grow from 15–18 km in Week 1 to a 35 km structured run in Week 11, the longest training run of the block, and the most direct preparation for race day.
The critical innovation in this plan is the introduction of active sections within the long run from Week 9 onward. Rather than running 28, 30, or 35 km at an easy pace throughout, the Peak phase long runs include a middle section at 5:15–5:30 per kilometer, just faster than race pace after an initial easy section has already induced meaningful fatigue. This structure is specifically designed to replicate the physiological challenge of the marathon’s second half: running at or near race pace when your glycogen stores are partially depleted, and your legs are already carrying significant muscular fatigue.
All easy sections of every long run are run at genuine easy, low heart rate pace. At weekly volumes reaching 99 km, the easy sections are not filler they are where aerobic adaptations accumulate, and connective tissue strengthens to handle the cumulative load.
The Fartlek Sessions
One element that distinguishes this plan from the half-marathon programs is the inclusion of fartlek sessions in the Build phase on Fridays. Rather than structured tempo runs with fixed pace targets, fartlek Swedish for “speed play” alternates 1 minute at a faster effort with 1 minute at a slower recovery effort across 6, 8, and 10 km blocks.
At first glance, fartlek looks less structured than a tempo run. In a marathon training context, it develops something different: the ability to modulate effort continuously and recover partially while still moving at pace. Over 42.2 km, a runner encounters terrain changes, competitor surges, and physical fluctuations that require exactly this kind of dynamic effort management. The fartlek sessions in Weeks 5 through 7 teach your body to handle these variations without losing overall rhythm — a skill that pays dividends specifically in the back half of the race.
As Ilya notes for Week 5: This is the first time the long run pushes you closer to marathon distance” and the fartlek is what sharpens your ability to handle the pace variation that real marathon racing demands.
Race Day Execution
Ilya’s Week 16 coach note contains the most precise race-day instruction in the plan: “Start conservatively, lock into your marathon pace, and stay patient. The last 10 km will be tough, but you’ll be ready.”
For sub-3:45, conservative means running the first 10 km at 5:25–5:28 per kilometer, 5 to 8 seconds per kilometer slower than goal pace. In a large marathon field with race-day excitement, this requires active restraint. It is worth it. Runners who go out at flat 5:20 from the gun consistently report pace deterioration between kilometer 30 and 35 exactly where the race is actually won or lost.
From kilometer 10 to kilometer 30, settle into the exact goal pace of 5:20 per kilometer. This should feel controlled and sustainable. The structured long runs in Weeks 9 through 11 have specifically prepared you for running at this effort level under fatigue. Your body knows this pace.
From kilometer 30 onward, as Ilya notes, it will get tough. This is not a sign that something has gone wrong it is the marathon doing what the marathon always does. Increase effort to hold pace rather than increasing pace. Fuel consistently. If you have run the first 30 km correctly, you have the reserves to hold 5:20 per kilometer to the finish. A 1:52:30 first half and a 1:52:29 second half is a near-perfect sub-3:45 execution.
What You Need Before You Start
GPS Watch
At 5:20 per kilometer across 42.2 km, pace precision over four hours is essential. A GPS watch with real-time pace display, lap splits, and auto-lap functionality is non-negotiable for executing the structured long runs in the Peak phase where you need to distinguish between your easy sections at 5:40–6:10 per kilometer and your active sections at 5:15–5:30 per kilometer with accuracy.
For runners who want the most complete picture, including race predictor functions, training readiness scores, and fueling reminders, the Garmin provides those tools at the volume and duration this plan targets. Best GPS Watches For Running
Running Shoes
Weekly volumes reach 99 km in peak weeks with long runs extending to 35 km. Shoe selection matters more at marathon distances than at any shorter race target. A well-cushioned daily trainer handles the easy runs, midweek mileage, and long run easy sections for the majority of your weekly kilometers across 16 weeks. A lighter, more responsive shoe can be reserved for interval sessions, tempo runs, and race day. Best Running Shoes
Recovery and Nutrition
At 57 to 99 km per week across 16 weeks, recovery is not optional; it is training. Three tools make a measurable difference at this volume across a four-month block.
A foam roller used after Tuesday interval sessions and Friday tempo and fartlek sessions reduces next-session stiffness. Magnesium supplementation before sleep supports muscle recovery during the demanding Peak weeks, particularly Weeks 10 and 11. For long runs of 90 minutes or more, which applies from Week 1 of this plan, carbohydrate intake during the run is essential: 30 to 60 grams per hour prevents the glycogen depletion that compromises the structured active sections of Peak phase long runs. Practice your exact race-day fueling strategy gel brand, quantities, and timing during every long run from Week 5 onward, so race day nutrition is a known variable, not an experiment. Best Electrolytes For Runners / Best Massage Guns
How to Get the Full Plan
This article explains the structure, methodology, and key training sessions of the Marathon Sub-3:45 plan. The complete 16-week schedule, including every session across all 16 weeks, full warm-up and cool-down routines, running drill guidance, all pace charts, and Ilya’s coach notes for every week, is available as a downloadable PDF.
About the Coach
This plan was created by Ilya Tyapkin, a professional marathon runner who represented his country at the 2016 Rio Olympic Games. Ilya coaches runners of all levels through structured training programs built on the same principles used in elite distance running. All training plans on esenbay.com are designed and reviewed by Ilya directly.
Frequently Asked Questions
How should I approach the structured long runs in the Peak phase?
Run the first easy section at genuinely easy effort, 5:40–6:10 per kilometer. Resist the temptation to run this section faster than prescribed. The active section should feel controlled and demanding approximately 5:15–5:30 per kilometer not a sprint. The final easy section will feel hard, no matter how correctly you run the first two sections. That is normal and intentional. Complete the full distance at controlled effort and even the final 10 km at a reduced but honest pace.
How important is fueling during long runs?
At marathon training volumes and long run distances reaching 35 km, fueling during runs is not optional from Week 5 onward it is part of the training. Practice taking gels or chews every 30 to 45 minutes on every long run above 90 minutes. Your stomach, like your legs, needs to be trained to process nutrition while running at pace. Runners who neglect this consistently report GI distress on race day that compromises both performance and experience.
What if I miss a session?
Skip it and move on. Never try to cram missed sessions. At 16 weeks with three built-in recovery weeks, the plan has significant flexibility to absorb occasional missed days without compromising the overall training effect. The recovery weeks at Weeks 4, 8, and 12 are specifically designed to absorb the minor inconsistencies that occur in any real-world training block.
