20-week marathon plan, the perfect duration?

12 weeks? 16 weeks? 20 weeks? 24 or more?  The duration of marathon preparation plans varies greatly. It is sometimes challenging to determine on your own what duration is suitable for your runner profile and goals. 

At Campus, we believe a longer preparation period offers multiple benefits. By working on a wide range of paces and maintaining gradual progress, you maximize your marathon success chances. 

Running a marathon isn't something you improvise. It is highly recommended to follow a structured preparation plan to successfully maintain a marathon pace over a distance of 42.195 km... And to ensure maximum enjoyment during marathon preparation and/or on race day by achieving the expected performance. 

The three key words for good preparation are consistency, graduality, and specificity. Consistency refers to the frequency of your workouts - for us, it is the number one progression factor. Your dedication and discipline will be rewarded. Graduality refers to a measured increase in training load (km per week and intensity) to avoid excessive fatigue and mechanical stress. This way, you'll greatly reduce the risk of injury, which is the top priority for any preparation. Indeed, injuries often occur after too rapid a change in mileage. Finally, specificity pertains to workouts done at your target race pace and on the race terrain you're preparing for. 

In marathon preparation, the concept of graduality is fundamental. The classic beginner's mistake is to increase their weekly mileage too abruptly and/or not adhere to recommended paces during workouts. The risk lies in the fact that their body is not yet ready to adapt, often leading to injuries. 

During your preparation, your longest runs will approach 2.5 hours. This is a prerequisite for preparing your body and mental strength to maintain the effort on marathon day. Of course, your longest runs will occur in the latter part of your preparation. 

Before that, a very gradual increase must be respected. The smaller the weekly variation, the better you will assimilate these challenging sessions. Generally, the increase from one week to the next will not exceed around 10%. Always aiming for improved assimilation and long-term mentality, it's also advised to include a lighter week after a three-week block of increased training volume.

This process will take time. That's why long marathon preparations are recommended. Because training for this distance may require a frequency and/or volume quite different from what you were used to practicing in previous months. The more different the preparation is from your usual training, the more recommended it is that it be long to respect the gradual increase in workload. 

This is even more true if you're a first-time marathoner or resuming training. You must be able to acquire or resume the habit of long runs of 1.5 hours and weekly consistency. 

A marathon preparation plan consists of three phases. 

First, the general preparation phase. The goal is to prepare you to approach the upcoming specific phase in good physical condition. The process is simple to understand. As your weekly mileage increases, you develop your recovery capacity and your ability to link workouts in the mid-term. Be careful to increase in line with previous months, as too strong an increase may lead you to injury or short-term non-assimilation.  However, it's essential to teach your body to recover well during marathon prep as the most intense weeks cause fatigue.

Doubling your mileage in one week just because you feel like it or your schedule allows it is pointless. 

It's crucial to build a good aerobic base as the foundation for your marathon preparation. This involves many runs at base endurance — you should be able to hold a conversation while running. You'll also introduce long runs, gradually extending their duration without exceeding 1h30 - 1h40 in the early weeks to prevent excessive fatigue. 

During this first phase, you'll also perform workouts of intervals and speed where running is at paces faster than your marathon pace. The goal here is twofold: to improve your engine's power (your maximal aerobic speed or MAS) and develop your running economy. In parallel, strength & conditioning is an excellent accompaniment, even a game changer, to effectively prepare your body to endure long-duration efforts. 

After the general preparation phase, gradually transition to the specific preparation. Your body is ready. It's time to focus on marathon pace and threshold workouts. The duration of long runs continues to gradually extend. Several long runs exceeding two hours are necessary to arrive prepared on marathon day. This second phase also includes intensity reminders, sometimes hill training workouts. You can find key workouts for marathon prep in this article. 

Finally, the third phase, known as the tapering phase, in the last two or three weeks of the plan is crucial. The volume and intensity levels are gradually reduced while maintaining workout frequency. The goal is to arrive as fresh and rested as possible on race day.  

12-week preparations are reserved for the most seasoned runners. Some elite runners even have express preparation plans lasting about ten weeks. It must be noted that these durations do not include the general preparation phase. Indeed, these runners already have an excellent physical condition, often the experience of several marathons and the habit of maintaining high weekly volume for part of the year. For them, the endurance and speed base is already established before starting the specific marathon preparation phase. This represents a minority of runners. 

For the vast majority of runners, the general preparation phase is essential. The longer this phase, the more solid the foundation will be. A four-week block: three weeks of increasing load followed by a recovery week is the minimum before starting specific preparation. So, 4 weeks + 12 weeks = 16 weeks of preparation. 

Adding a second work block during general preparation results in a total duration of 20 weeks. This is a great compromise if you're gearing up for your first marathon experience after having participated in shorter competitions. There cannot be a perfect duration as it depends on each runner's profile. But, in many cases, whether your main goal is to cross the finish line or improve your Personal Record, a 20-week plan will help you fully optimize your abilities.

If you have enough time to prepare for your dream marathon, a 24-week plan will offer even more graduality and comfort. This will also generate less stress compared to a short preparation.

Around six months is also the minimum duration recommended for novice runners to properly adhere to the process. It is also a good duration to more easily allow for intermediate races, as there is time to recover and improve form between each race, even without specific preparation.

Complete beginners, who have never practiced running, should first prepare for an intermediate distance like the half-marathon. Preparing for a half marathon is less demanding than marathon preparation and allows you to start structuring your training. It's important not to skip steps. The idea is not to suffer agony during your first marathon, but rather to aim for long-term progress and enjoy your practice, maybe even consider continuing to run after the marathon. 👀