The Ultimate Half-Marathon Training Plan

As summer draws to a close, runners are hitting the streets and parks again, making the most of the cooler but still pleasant weather. Many are already gearing up for winter half marathons, with plenty of events planned across the UK in the coming months.


If you've been thinking about taking on a new challenge, why not consider joining one? And if you’re worried it’s too late to start training, don’t be! There’s still ample time to prepare for a winter race.


In this article, we answer some of the most common questions about half marathons and offer a comprehensive training plan to help you get race-ready in 16 weeks or less.

Fabletics Men Run

How long is a half-marathon in miles/kilometres? 

A full marathon is 42 km (or 26.2 miles), so a half-one will be 21 km (or 13.1 miles). Doing a half-marathon is a great idea (and a perfectly achievable one) for runners who can do a 5k or a 10k run without any issues. So, if that’s you, then you can start preparing for it!


Your first half-marathon should probably take around 2 to 3 hours, unless you walk occasionally instead of running, or the weather is moody - then it will take you a little longer. It’s worth knowing that in most official half-marathon events there is a time limit for completing it, which is usually around 4.5 hours.


How long should I train for? 

If you tap this question into Google, you’ll see all sorts of answers. Some are as short as four weeks, while others last 16. How can you tell which duration is most realistic for you?


This comes down to a few factors:

  • your current fitness level – do you engage in any form of training?
  • are you completely new to running?
  • how much time can you dedicate to working out each week?
  • what’s your end goal? Do you care about the time, or do you simply want to get past the finish line?


For the sake of this post, let’s assume you’re a novice runner and can dedicate 16 weeks to gradually building up your strength and cardiovascular endurance. If you start this June or July and follow a training plan (like the one we’ve put together for you in the next section), you can definitely consider signing up to an October or November 21k race.

Fabletics Group Run


Half-marathon training plan to get you started


Here is a suggested 16-week-long training plan.

There are two so-called ‘easy runs’, which are two shorter distances, and then one longer run planned for the weekend. Each week, the ‘easy runs’ get extended by 800 metres, and the longer ones by 1.6 kilometres. We’ve also included ‘tempo runs’ from weeks 8 through to 14, during which you’ll want to push yourself to achieve your fastest continuous run without any walking breaks.


We suggest that you get at least two full rest days per week, and either one or two cross-training sessions to build up your muscle endurance (more on why that’s important later).


Notice that you don’t reach the half-marathon distance – not until the actual race. By week 12, you’ll run 20k and then start slowly reducing the intensity of your runs. This is intentional, as we want to preserve your stamina and allow for decent recovery before the big day.


Since we’re all different, you might find yourself progressing faster than the plan foresees. Or, you might experience the contrary. Treat the table below as your starting point, and if you’re concerned about any symptoms, consult a health professional.

Fabletics Half-Marathon Training Plan


Ready to head out for your first run? Make sure to always:


  • Start your practice with a warm-up 
  • End each session with a cool-down, i.e., walking as your heart rate slowly decreases
  • Drink plenty of water – you need to replenish all the fluids you’ve sweated out 
  • Follow your training with a protein-rich meal – naturally, you should also eat healthy all week long.


Strength training, endurance training, and effective rest days 

Let’s go back to the time in between your runs – it’s as crucial as the days you reach your planned kilometres.


Why does resistance training matter for runners? It helps you address any weaknesses and imbalances which could lead to injury the more you run, and the longer these issues remain unaddressed. 


What kind of activity should you engage in? Things like lifting weights and performing lunges and squats will all be great, as they’ll help you build muscle and create that functional ‘core’ needed when you run longer distances.


Endurance training – and intervals, in particular – on the other hand, can be a great way to quickly enhance your cardiovascular health. If you struggle with completing a distance on a single attempt without running out of breath, you could introduce a sequence, like a two-minute run, one-minute walk, five to ten times. You’ll cover the same running distance, but the walks in between will help your heart recoup. 


Increasing the distance and shortening the low-intensity parts of your intervals gradually will help your body adapt to long-distance runs – and potentially contribute to a better time on the finish line.

Finally, there’s the topic of effective rest days. Don’t skip them, as that’s when your body recovers from your runs and strength training, enabling progress. 


Set aside time for enough rest to enjoy an injury-free half-marathon.


Stretching & nutrition 

While being in great shape isn’t necessary to take part in a half-marathon, being able to complete it in less than 4.5 hours requires good fitness. And this not only means exercising regularly, with stretching included, but also following the right diet. 


Ideally, you should pay attention to what you eat throughout the year, but if you can’t, then try to modify your eating habits while preparing for the run. You need to stock up on glycogen – this means eating vegetables, fruits, starches, and proteins. Stay away from fatty foods, as they will negatively impact digestion, and as a result your performance. 


Let’s take a closer look at the foods you should consume.

  • Fresh fruits and veggies – try to eat twice as many vegetables as fruit to avoid too much sugar. Both are great energy boosters as they provide a lot of fibre and vitamins.
  • Carbohydrates – earlier we mentioned that you needed a lot of glycogen, and carbohydrates are a great source of it. Try to eat them with every meal, on a daily basis, and pick wholemeal foods (including bread, rice, and pasta) as they have more fibre. 
  • Proteins – you can eat both animal and vegetable proteins – whichever you prefer. However, if you love meat, then try to stick with poultry rather than red meat as the latter is harder on your digestive system. 


A few more tips: Use olive oil for cooking, reduce butter, and eliminate saturated fats. Drink plenty of water, and try your best to limit your alcohol intake. 


Healthy diet is just one part of the equation. Running regularly might strain your muscle, which is why you need to stretch regularly. It will help you with:


  • Preventing injuries – stretching is great for warming up your muscles. They become more elastic and flexible, which reduces the risk of injuries including strains and sprains. 
  • Improving performance – it loosens up your muscles which enhances your range of motion and muscle efficiency, resulting in better performance. 
  • Enhancing blood flow – stretching causes muscle oxygenation, which has a positive impact on your physical performance. 
  • Reducing muscle stiffness – as it improves range of motion and flexibility, stretching reduces muscle toughness, so you can run more comfortably without worrying about injuries. 
  • Activating key muscle groups – running is heavy on your joints and muscles. Dynamic stretching can help you wake up your key muscle groups like glutes, hamstrings, and calves, so you’re ready to perform at your best. 


Listening to your body and common injuries to look out for 

Every half-marathon training plan is designed in a way to improve your muscle fitness and performance. And while it’s created to build endurance progressively, which should be safe, sometimes injuries happen. These can be as innocent as blisters (although sometimes they can be a real nightmare), joint pains and sprains, or as serious as fractures, shin splints, and Achilles tendonitis. It’s important to recognize injury symptoms to act and manage them quickly to minimise damage. For example, pain and inflammation might suggest stress fractures or tendonitis.


It’s really important to listen to your body. Do you feel pain or fatigue? You need to learn how to differentiate regular muscle soreness from persistent pain. If you notice any unusual symptoms beyond simple muscle tiredness, such as sharp pain or swelling, it’s best to see a healthcare professional who can provide proper guidance. 



Dress for success with the Fabletics Run Shop 

Wearing the right outfit is another runner’s secret. While it’s not as obvious a performance factor as getting enough sleep and eating well, it’s important that your clothes keep you comfortable as you train for your first 21k, especially as the weather's getting cooler and evenings are getting longer.

You can choose from a variety of performance outfits made of moisture-wicking, anti-microbial, breathable, and super stretchy fabric. Our runner collection includes:

Visit our Men's or Women's Run Shop to find the ideal outfit for your first half-marathon.


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