How long do I need to train for the London Marathon (and other considerations)?

If you’re gearing up for the London Marathon, it’s time to cut through the fluff and focus on what works. Training for 26.2 miles is no small feat, but with the right plan, mindset, and discipline, you’ll make it to The Mall with a smile (or at least without crumbling at mile 23).

Understanding your Marathon training timeline

This is going to be different for novice and seasoned runners obviously, but you’re generally looking at 16–20 weeks of solid, structured training. That’s about four to five months of graft, starting with shorter runs and gradually building up your mileage. No shortcuts here—this timeline gives your body time to adapt without breaking down. The issue with the London is that these four months will fall during the deep, bleak winter, and winter training does have its drawbacks. But if you’re aiming to run a marathon, the weather isn’t going to stop you!

Understanding the physiological adaptations

Without delving too much into the science behind marathon training, it's crucial to recognise the physiological adaptations that occur during the 16 to 20-week timeline. The good news? Your body gets better at running if you train right.

• Your heart gets stronger: Pumps blood more efficiently to keep you going.

• Your muscles adapt: They develop slow-twitch fibres for endurance and grow more mitochondria to produce energy.

• Your joints and tendons toughen up: Making you more resilient to the pounding of those long runs.

But you’ve got to respect the process. Try to rush it, and you’ll risk injury or burnout.

Set goals that work for you

Whether you’re chasing a PB or just want to finish in one piece, set clear goals. The London Marathon isn’t just for seasoned pros—you’ll see all abilities out there. A good approach? Set three goals:

1. A Goal: Your dream finish time.

2. B Goal: A realistic target if things don’t go perfectly.

3. C Goal: Just get across the finish line!

Your training tailored to you and your goals

If this is your first marathon, and you want to train for a specific finish time; start by testing yourself in a 10K or half marathon to gauge your pace. Use that data to structure your plan. If you’re unsure, consider expert advice. The physios from our Running clinic can build a plan tailored to your fitness level, goals, and schedule - just send us an email / whatsapp or book yourself in to get started. Having a clear, tailored plan will make such a difference to your training.

Build your base first if you're new to mid/long distance running

If you’re completely new to running, you won't be able to dive straight into marathon training. We see this all to often, only for people to injure themselves right before the race and having to pull out. Instead, spend 3–4 months building a solid base:

• Run 3–4 times a week: Easy, consistent miles—no need to go fast. You will be much better doing lots of mini runs that you don't need days to recover from, than just trying to do one long run a week.

• Work up to 15–25 miles per week: Gradual increases to avoid injury, a general rul of thumb is 20% week on week, but making sure to include deloading weeks.

  
  

This foundation will make transitioning to marathon-specific training much easier.

Know the course

This is London—expect the buzz of the crowd and world-famous sights... An amazing course, but so many new marathon runners get gassed out too quickly because of that atmosphere!

Here’s a quick breakdown:

• Start in Greenwich and Blackheath: Smooth residential streets to ease you in.

• Halfway at Tower Bridge: Take in the views, but don’t get too hyped—it’s only halfway!

• Canary Wharf to Embankment: The grind starts here. Prepare for twists and turns.

• The Mall finish: Push through and soak up the glory.

People will obviously tell you about "The Wall" at around 20 miles (or 32 km). That’s where smart pacing and proper fueling come into play—but most importantly, it’s about your training. Your body needs to be accustomed to the stress and impact of pounding tarmac for that long. If you haven’t trained properly or built the necessary muscular adaptations, the 30k mark is where you’ll start to feel it. Your body will begin to break down. We don't need to be too clever about it, only need to train right for it!

Avoid rookie mistakes

Most mistakes boil down to this: trying to do too much, too soon. Common pitfalls include:

• Skipping rest days: Recovery is where the magic happens.

• Overtraining: Gradual loading is key.

• Ignoring strength work: A strong core and legs can save you late in the race.

• Not training enough: 42k isn't nothing, and we generally consider that you need at least the double amount of mileage per week at the peak of your training. This means 80k+ weeks. Anything lower than this and you risk not having the right adaptations for race day.

Recovery weeks, strategically placed every fourth week, allow your body to absorb the training benefits while preventing burnout. Additionally, a two- to three-week taper is recommended leading up to the marathon.

Listen to your body and get help early if you need it. A niggle ignored today can become a full-blown injury tomorrow. Often we can keep you running with an early-stage injury, but wait too late and you'll have to be stopping entirely.

Need help?

Training for a marathon isn’t always straightforward. If you’re feeling overwhelmed, consider expert support. Our Running Clinic offers running analysis, tailored training plans and running physio sessions, to help you hit your goals and keep injuries at bay.

See you on race day!

FANCY HAVING ONE OF OUR PHYSIOS HELP YOU PLAN YOUR MARATHON TRAINING OR CHECK A NIGGLE BEFORE IT'S TOO LATE?

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