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Your Full Marathon Training Plan - 16 & 20 Weeks

Page last updated: 22nd March 2022

Jump straight to the training plans

If you've decided this is your year for taking on the challenge of the marathon, you'll need to make sure you plan your training effectively. This guide is here to help you prepare for this exhilarating event, and includes comprehensive beginner, intermediate, and advanced 16 and 20 week marathon plans created by Run Coach and PureGym Personal Trainer, Ian Scarrott.

What is a marathon?

A marathon is a road running race that covers a demanding distance of 26.2 miles (42.2km), usually undertaken in one go. Marathon events take place throughout the year, all across the U.K., as well as in most countries across the globe. The event is technically a race, particularly for the professional runners who take part, but for many runners it's seen as a personal challenge and a demanding goal to aspire towards. Some participants take part with a goal of simply completing the course, whether that's by running, walking or by wheelchair, while others focus on finishing in a particular time, perhaps even improving on their last marathon time.

What are the benefits of training for a marathon?

Training for a marathon is challenging, but it's got some great perks too. If doing it for the challenge (or the bragging rights) isn't enough for you, these are some of the benefits you can get from training for a marathon:

  • Improved cardiovascular fitness: Regular aerobic exercise improves your cardiovascular fitness, which can help with reducing your risk of developing heart disease. Plus, improved oxygen uptake in the lungs and heart can help a person sustain physical activity for longer, which is key when running marathon distances.
  • Improved mood: Multiple studies have shown that regular aerobic exercise, including running, can help to improve mood. Some people report a "runners high" - a feeling of euphoria and lessened anxiety, which has been associated with long-duration, rhythmic-type exercise like a marathon.
  • Strengthened joints: Running has been shown to strengthen the ligaments that help support joints and protect against development of osteoarthritis later in life.
  • Being part of a community: Running doesn't have to be a solo hobby or sport. There are many running groups across the UK you can be a part of and get reciprocal support. Running can be a form of exercise or sport but it can also be a social activity - albeit from a distance or virtually for the time being!
  • Way to relieve stress: Exercise and other physical activity can help produce endorphins and reduce stress hormones, which in turn can help to reduce feelings of stress. Including some form of exercise like running can be a way to not just improve your physical health but help manage your mental health too.
  • Better sleep: Research suggests that regular exercise can help to improve sleep, which can then impact how you lead you day to day. So if you like to sleep faster and want to wake up feeling rested? Running may help!
  • Boost ability to focus: Exercise has been shown to increase blood flow throughout the body, including the brain. The increased blood flow can mean more oxygen being transported to the brain, helping with our ability to focus better. 
  • Weight management: Running uses a lot of energy, so if you're wanting to lose weight, it can be used to help with weight management.

Why is training for a marathon important?

Running 26.2 miles is no walk in the park, and even some of the fittest runners find it to be an intense challenge. This event will take its toll both physically and mentally, so it's extremely important to prepare your body and your mind before taking part. Your muscular, cardiovascular and energy systems need to be built up over time so they're in the best position for running continuously for (on average) four to five hours straight.

Following a marathon training plan helps you to build up your mental and physical fitness and endurance so you're race ready, and also means you're less likely to experience injury or exhaustion. Plus, being in shape for the marathon will mean your body takes less time to recover afterwards.

How long does it take to train for a marathon?

This very much depends on your starting fitness and ability levels - if you're a complete running newbie, then you're best starting with training for 5k and 10k events, and even considering a half marathon before you jump straight to the full marathon. For first time marathoners, you should generally expect to spend around five to six months training for the big event. This may seem like a long time, but as mentioned above, it's vital to take the time to gradually strengthen and prepare your body for such a long-distance run. We've set out a 20 week marathon plan below, but you'll need that running experience before getting started.

What is the best training plan for a marathon?

There are a host of different types of training plans available to suit different fitness levels, time frames and objectives, so finding the perfect one for you starts with working out what you want from your marathon.

A good rule of thumb for marathon training is to run three times a week, including one long run a week that builds up over the months. You should also include a couple of days set aside for strength or functional training and at least two rest days to recover (which could include some gentle yoga or stretching to work on your flexibility and mobility). This will ensure that while you're building up your running ability, you'll also be strengthening your muscles so they're in the best shape possible to power you forward for the entirety of the run.

Also, when the weather is bad, you might be tempted to do all of your training on a treadmill, but it's worth factoring in plenty of outdoor runs so you can acclimatise to the different types of conditions you might face on the day. Running inside can be very different to running against the wind, through rain, or in hot sunshine, so ideally you'll want to have a good idea of what to expect should you face any extreme weather on the day.

Likewise, think about the route your planned marathon will be taking. If, for example, there are hills or different types of terrain on your marathon route - then try to factor these into your training plan, so your body can get used to tackling different gradients and ground types.

Our 20 week marathon training plan includes:

  • Pace recommendations
  • Strength and conditioning workouts
  • Mobility work
  • 3x runs per week
  • Training and nutrition advice

Training to boost your marathon performance

For those looking to improve speed and beat a previous marathon time, you'll want to integrate tempo runs (also known as threshold runs). These are runs where you boost your speed or energy output, pushing yourself harder to improve your body's capabilities. One way to do this is to set your running tempo to around 80-90% of your maximum heart rate - which is where your lactate threshold usually falls. This will be much faster than the pace you run the actual marathon, but is a great way to enhance your fitness levels. It works by helping to boost your lactate threshold and helps your body to become more efficient at clearing the by-products of lactate production which cause fatigue.

Download our free PureGym marathon training plans 

PureGym Personal Trainer and Triclub Run Coach, Ian Scarrott, has created a comprehensive training plan to get you marathon ready for beginner, intermediate, and advanced runners. The plans combine:

  • Speed runs
  • Endurance runs
  • Recovery runs
  • Strength and conditioning

The plans requires a base level of running fitness, so if you're completely new we suggest checking out our guides to training for a 5k or running a 10k before picking up with this plan. Likewise, a safe starting point could also be our 13 week half marathon training plan, before you immediately start on a full marathon.

The plan also includes rest days. These are very important - don't be tempted to skip these. You need to allow your joints time to recover and your muscles time to heal and strengthen. If you still want to stay active on these days, maybe consider some yoga or light stretching to work on your flexibility or mobility without impacting on your overall recovery. Find out more about rest days with our 'why rest days are important' article. 

As always, don't forget to warm up before each training session (a brisk 5 - 10 minute walk, or some dynamic stretches can do the trick here) and to cool down afterwards (ideally some static stretches to promote blood flow, reduce stiffness and boost your flexibility). 

If you're looking to supercharge your diet to help fuel your training and maximise recovery, check out our marathon training diet advice here.

Need to work on your leg strength, functional fitness or core for your next running event? Need to work on your leg strength, functional fitness or core for your next running event? Our Mud Run training plan is a great all-rounder for working on strength and cardio.

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