Moving from the 10K to the half marathon: how should you adapt your training?

What is the difference between a 10K and a half marathon?

Does your experience as a runner and your recent 10K races give you the confidence to step up to a longer distance? Well done on your progress. A new challenge awaits over the half marathon distance. Moving up in distance can be exciting and motivating, but it can also be stressful. That is understandable when you are doubling the number of kilometres, right? By definition, a half marathon is half the distance of a marathon (42.195 km), or 21.0975 km. That is the main difference between the two race formats. More kilometres inevitably means a longer time on your feet. The 10K world record is held by Ugandan Joshua Cheptegei in 26:38. The half marathon world record is held by his compatriot Jacob Kiplimo in 56:42. The duration of the effort is therefore more than twice as long, even for the world's best runners.

When you run for longer, your race pace is also different from your 10K pace. The target pace you work on during half marathon-specific sessions will not be the same as your 10K-specific pace. If you have never needed a fuelling strategy for a 10K, you will need to think about one for your first half marathon. Finally, although there are some similarities, 10K and half marathon training are different, as is post-race recovery. You will need to devote a little more time to your half marathon preparation and increase your weekly mileage.

How long should half marathon training last?

If you have already trained for a 10K, you have probably spread your preparation over several weeks. Of course, the length of your training plan depends on many factors, particularly your experience as a runner. For this relatively accessible distance, six weeks may be enough to become a 10K finisher. For the half marathon, you will need a little longer. Coming from the 10K, you have already built up a certain amount of mileage and gained race experience. To give yourself enough time to prepare for your half marathon, make the transition successfully, avoid injury and enjoy the race, eight to 12 weeks of preparation is recommended. You can follow a specific training plan through the different coaching options available to you. This eight- to 12-week plan will help you build your mileage gradually and complete half marathon-specific sessions at race pace. Naturally, depending on your availability and your profile, you may do more or fewer training sessions each week.

Adapting your training to move up in distance

Let us look in a little more detail at how to adapt your training for your first half marathon. If you followed a training plan for your previous 10Ks, you already have some understanding of how to train for a road race over several kilometres. The foundations of half marathon training remain fairly similar to those of 10K training: building endurance, working at target pace, long runs, rest, a race phase and recovery.

➜ Easy running accounts for around 70% of your weekly mileage. These sessions will help improve your endurance, in other words, your ability to hold a pace over time. Quite simply, these are your easy runs!

➜ Specific sessions are essential for working on your race pace. For example, if your goal is a two-hour half marathon, your race pace, and therefore your training pace, will be 10.5 km/h, or 5:41 per kilometre.

➜ Long runs allow you to gradually increase your weekly mileage. They are essential because they help your body get used to running for almost as long as your expected race time. You can include some half marathon pace during your long runs, for example, a 15 km run with 20 minutes at half marathon pace.

Moving up to a longer distance does not mean you should abandon speed sessions. Maintaining a few high-intensity workouts with shorter work intervals is strongly recommended. This will allow you to continue developing your maximal aerobic speed and, as a result, improve your various paces, from easy running to race pace.

The biggest risk when increasing the distance is injury: doing too much, too soon, too fast. Do not overlook rest periods or the need to increase your training load gradually. Adding strength training is highly relevant for reducing the risk of injury and improving your muscular capabilities.

Common mistakes to avoid

When moving from the 10K to the half marathon, it is easy to make a few common mistakes. Here are the ones you should avoid at all costs before your first half marathon:

✗ Increasing your mileage too quickly: the main risk is injury. It is better to do a little less but complete your training properly than to do too much and get injured before race day.

✗ Neglecting recovery: half marathon training is much more demanding than 10K training. You will increase the duration of your runs and your total mileage. Do not forget to take rest days.

✗ Failing to test your fuelling: arriving on race day without having tested your fuelling strategy can lead to unpleasant surprises, such as digestive problems or a sudden drop in energy. Use some of your long runs to test different products.

✗ Starting too fast on race day: remember, you are setting out for an effort that will be significantly longer than a 10K. The first few minutes may feel easy, but that does not mean you should increase your pace. Stick to the pace you have practised in training and stay consistent from kilometre to kilometre.

✗ : if you think preparing for a half marathon is all about interval training, think again. Long runs are essential for getting your body used to efforts lasting 90 minutes or more.

✗ Neglecting strength training: strength training is the most overlooked part of training plans, yet it is incredibly important. Reducing the risk of injury and improving muscular strength, power and resilience are all good reasons to include it in your preparation.

✗ Underestimating the importance of the mental side: when your legs can no longer keep going, your mind takes over. You can work on your mental game by using visualisation techniques with a mental coach.

The half marathon is much more than just a race: it is the ideal stepping stone between the 10K and the marathon. By taking on 21.1 km, you will discover a new dimension of endurance, learn to manage your effort more effectively and lay solid foundations for perhaps running a marathon one day. Do not hesitate to work with a coach to make the move from 10K to half marathon and enjoy a great sporting experience.

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