Planning an autumn marathon starting in early May offers a twenty-week timeframe: the ideal period to gradually prepare muscles and joints, reducing the risk of injury.
- Preparing for a 42-kilometer race takes time. Twenty weeks (5 months) allow the body to adapt to the new workload without rushing.
- The months of May and June are dedicated to aerobic base building: you run at an easy pace to accustom tendons and joints to repeated effort.
- July and August introduce the first long runs. The heat requires careful management, shifting runs to the cooler hours and focusing on hydration.
- September is the peak month: you tackle the longest runs to accustom the body and mind to the race distance.
- October is the recovery month (tapering): mileage is reduced to let the muscles rest and store the energy needed for race day.
The Importance of Timing: Why 5 Months is the Optimal Period
The marathon is a distance that requires strict respect for biological times. Starting preparation well in advance is the first rule to avoid overloads and inflammation. A period of about 20 weeks, or 5 months, offers the necessary space to increase mileage in a constant and well-distributed manner.
The cardiovascular system adapts quickly, but connective tissues like tendons, ligaments, and bones have a slower metabolism. They require months of measured stress to strengthen and be able to withstand the impact of thousands of steps on the asphalt. Starting in May for a race scheduled in October/November means giving your body time to build this structural resistance without skipping steps.
May and June: Building the Structural Base and Tendons
The first two months of the program must be dedicated almost entirely to building the aerobic base. In this phase, the goal is not speed, but getting used to spending time on your feet.
It involves performing workouts at a relaxed pace, where it’s possible to maintain a conversation without breathlessness. This type of running – the easy run – is the most effective way to increase the number of small blood vessels in the muscles and improve the body’s ability to use oxygen. There is no need to rush to introduce demanding workouts like intervals: in these eight weeks, the focus is entirely on the consistency of the runs and the progressive strengthening of the joints.
July and August: Managing Volume During the Hot Season
With the arrival of summer, the training program involves the introduction of the first true long runs and quality workouts (important for improving technique and speed), necessary to prepare for the 42 kilometers. However, the heat and humidity represent a significant logistical challenge.
Cardiovascular effort increases due to high temperatures. To manage the required mileage volume, it becomes advisable to shift runs to the early morning or late evening hours. In this phase, hydration and the supplementation of mineral salts take on a leading role. It is also the time when you start accustoming the digestive system to the intake of gels or liquid carbohydrates during exertion, testing the nutritional strategies that will be used in the race.
September: Peak Mileage and Specific Long Runs
September represents the heart of the preparation. Temperatures start to drop, offering thermal relief, while the training program reaches its highest volume. This is the month of the “specific long runs,” meaning runs that exceed 28-30 kilometers.
These outings not only serve to prepare the muscles for prolonged fatigue, but they also have a specific physiological function: teaching the body to use fats as an energy source, sparing the sugar (glycogen) stores that tend to deplete after the first half of the marathon. Tackling these distances in training also provides the mental awareness needed to manage fatigue and overcome difficulties on race day.
October: The Unload and Tapering Strategy
The last three weeks before the marathon mark the beginning of the unloading phase, the tapering. After months of building, the work is done. The goal now is no longer to train more, but to show up at the starting line fresh and rested.
During this period, the total volume of kilometers is progressively reduced. Some short runs with small race-pace touches are maintained to keep the legs reactive, but deep fatigue is eliminated. This reduction in workload allows the muscle fibers to repair the small damages accumulated in previous months and the muscles to top up their energy. It is a phase that requires patience and trust in the work done during the summer.