Last updated: 18th February 2026
In a rush? Here’s what you need to know:
-
Most marathon injuries are caused by load increasing faster than your body can adapt. Fitness improves quickly, but tendons, bones, and connective tissue need time to catch up.
-
Common issues like knee pain, Achilles problems, and plantar fasciitis usually follow predictable patterns. Gradual mileage increases, strength work, and proper recovery prevent most of them.
-
Consistency beats intensity. Keep easy runs easy, build mileage in waves, maintain basic strength training, and prioritise sleep and fuelling.
-
Listen early, not late. If pain worsens across consecutive runs or changes how you move, adjust immediately. Short-term rest protects long-term progress.
Contents
Marathon training has a way of feeling brilliant… right up until it doesn’t.
One week you’re ticking off long runs, feeling fitter than you ever have. The next, there’s a dull ache in your knee, a tight Achilles that won’t loosen, or a foot that starts complaining the moment you get out of bed. You tell yourself it’s nothing. Everyone gets niggles, right?
Sometimes they are. Often, they’re not.
The good news is most marathon injuries aren’t bad luck. They’re predictable. And with the right approach, they’re largely avoidable.
In this guide, we’ll look at why marathon training breaks so many runners, where injuries tend to show up, and how to structure your build-up so you reach the start line feeling strong, not held together with tape and hope.
Why marathon training causes injuries
One of the most common things we hear from runners dealing with an injury is, “But my fitness was great.”
And they’re usually right. Aerobically, they were ready. Physically, their body just hadn’t caught up yet.
Fitness improves faster than your body can adapt
Your heart and lungs are quick learners. Give them a few weeks of consistent running, and they’ll happily handle longer distances at a pace that once felt uncomfortable. That’s why marathon training often feels easier than expected in the early stages.
The problem is that the rest of your body doesn’t adapt at the same speed.
Tendons, ligaments, bones, and fascia need time to strengthen. A lot of time. When mileage increases faster than those tissues can cope with, stress starts to build quietly in the background. Nothing dramatic happens at first, just a bit of tightness here, a twinge there.
That’s often where runners get caught out. Feeling fit encourages you to do more, even though the structures absorbing the impact aren’t ready for it yet. Over time, that imbalance turns into the kind of injury that doesn’t go away with a couple of easy days.
Repetition is the real enemy
Marathon training isn’t brutal because of one bad run. It’s brutal because of how similar so many runs are.
Think about it. You run the same routes, at similar paces, in the same shoes, week after week. Each run on its own is manageable. But stack them together and the load becomes significant, especially once fatigue starts creeping in.
Every step places stress through the same tissues. If something in your movement pattern, footwear, or recovery isn’t quite right, that stress keeps landing in the same place. Over time, that’s how niggles turn into overuse injuries.
It’s not that running is harmful. It’s that doing the same thing repeatedly under increasing fatigue eventually exposes weak points.
Where things usually start to unravel
There’s a point in most marathon plans where enthusiasm is high, but the body needs a bit more care.
For many runners, this danger zone sits somewhere in the middle to later stages of training. Weekly mileage is climbing, long runs are eating into weekends, and recovery starts getting squeezed around work, family, and life in general.
Strength work is often the first thing to go. Sleep becomes inconsistent. Easy runs drift a little faster than they should. None of this feels like a big deal at the time, until something starts to complain.
That’s usually when runners decide to “push through and see how it goes”. Sometimes they get away with it. But usually that’s the moment the marathon build-up starts going off course.
Understanding why this happens, and spotting it early, is one of the biggest steps you can take towards staying injury-free.
The most common marathon injuries (and why they happen)
Most marathon injuries aren’t random. They follow familiar patterns, tend to show up at predictable points in training, and usually give warning signs long before they stop you running.
The problem is that those signs are easy to brush off when you’ve got a plan to follow and a race date in the diary.
-
Knee pain is the most common complaint. It’s rarely a knee problem in isolation. As mileage increases and fatigue builds, control through the hips and ankles can drop slightly, shifting more load into the knee. Downhill running, cambered roads, and sudden jumps in long-run distance make this worse.
-
Achilles pain often appears when runners increase mileage and intensity at the same time. The Achilles stores and releases energy with every step, so volume adds up fast, especially if calves are tired or shoes change suddenly.
-
Plantar fasciitis tends to come from cumulative overload. High mileage, tight calves, hard surfaces, and poor recovery all place repeated strain through the foot until it starts to protest.
-
Hip and glute issues usually show up later in runs, when fatigue exposes weak stabilisers, often after strength work has quietly dropped off.
Across the board, the pattern is the same. Load increases faster than the body can adapt. Gradual progression, strength work, and early response to niggles are what keep these injuries at bay.
The right footwear will also help, especially with the impact on your knees. Check out our race training collection to find everything you need to get started.
How to reduce injury risk during marathon training
Staying injury-free during marathon training isn’t about finding a magic exercise or following a flawless plan. It’s about making smart, sensible decisions week after week and avoiding the handful of mistakes that trip runners up.
Here’s what that looks like in practice:
1. Increase mileage gradually – most injuries happen when weekly volume climbs faster than your body can cope with. The long run isn’t usually the problem, it’s how quickly total weekly volume increases around it. Build in small waves. Let mileage rise for two or three weeks, then ease back slightly. Cutback weeks aren’t lost progress. They’re what make progress possible.
2. Keep easy runs easy – when every run drifts into “moderately hard”, fatigue builds quietly in the background. Easy runs should feel comfortable. If you can’t chat in full sentences, you’re probably running too fast. Slowing down on easy days usually leads to better long runs and fewer injuries.
3. Maintain basic strength work – you don’t need marathon-specific gym sessions, but you do need strong calves, glutes, and hips to handle increasing mileage. Two short strength sessions a week can dramatically reduce the risk of Achilles, knee, and hip issues.
4. Prioritise recovery as much as training – sometimes the smartest training decision isn’t doing more. It’s doing enough. Sleep well, fuel properly, and allow your body time to catch up. Running in the same shoes concentrates stress in the same tissues. Rotating pairs introduces small variations that help spread the load. At Up & Running, you can get a FREE gait analysis in-store to help you find the right footwear to train in.
Most of the runners who make it to the start line healthy aren’t doing anything extreme. They’re just doing the basics consistently and respecting the signals their body gives them along the way.
If you’re unsure about footwear, your local Up & Running store can point you in the right direction.
When to push through discomfort, and when to stop
One of the hardest parts of marathon training is knowing whether the pain you’re feeling is something to work through or something that needs attention.
Every marathon runner deals with discomfort. Heavy legs, general soreness, and the odd ache are all part of training. The challenge is telling the difference between normal fatigue and the early signs of an injury that could derail your build-up.
A useful way to think about this is symmetry and progression.
General training soreness tends to:
-
Affect both sides of the body
-
Ease as you warm up
-
Settle within a day or two
Early injury pain usually behaves differently. It’s more likely to be:
-
Localised to one specific spot
-
Noticeable at the start of a run
-
More intense or persistent after training
If pain sharpens, spreads, or shows up earlier each time you head out, that’s a sign to intervene.
A helpful rule is the two-run test. If the issue worsens over two runs in a row, it’s time to adjust. That might mean reducing mileage, replacing a session with cross-training, or taking a few full rest days.
Skipping a run or taking a few easier days can feel like a step backwards, especially when you’ve been following a plan closely. But in reality, short-term rest is almost always the faster route back to consistent training.
Fitness is surprisingly resilient. Injuries are not. Backing off at the first sign of trouble might cost you a session or two, whereas pushing through can cost you months.
Most marathon-ending injuries don’t come from one dramatic moment. They come from repeatedly choosing to “see how it goes”.
Listening early is what keeps you training.
How to prepare for a marathon
A marathon build-up works best when it follows a simple principle: apply stress gradually, then give the body enough support to adapt.
With that in mind, let’s look at how to prepare for a marathon. We’ve put together a three-month plan, but you can adjust this depending on your fitness levels and availability. The key thing to remember is not to rush the process.
Month 1: building the foundation
The first month is about consistency and habit-building, not chasing pace or distance.
Running should feel controlled and comfortable. Most sessions sit firmly in the “easy” zone, with one longer run each week that increases gradually. This phase is about preparing your body to tolerate more work later on.
Pace discipline matters here. Running too fast early on doesn’t make you fitter quicker, but it does increase fatigue and injury risk. Easy runs should feel relaxed enough that you could hold a conversation without thinking about it.
This is also the time to dial in health basics. Regular sleep, simple mobility work, and light strength training (particularly calves, glutes, hips, and feet) help build resilience early, when the body is most receptive to it.
Food and hydration shouldn’t be an afterthought. Eating regularly, fuelling runs properly, and staying hydrated day-to-day lays the groundwork for harder training later. You don’t need to obsess. Just be consistent.
And remember to train in the right footwear. If you’re unsure where to start, an Up & Running specialist can help.
Month 2: add structure and control
This is the phase where marathon training starts to feel real.
Weekly mileage increases, long runs stretch further, and you may introduce small amounts of controlled pace work. That might mean short sections at marathon pace during a long run or a single quality session in the week, not multiple hard efforts stacked together.
The key here is balance. Easy runs still need to stay easy. Most injuries occur in this phase because runners let everything drift slightly harder as fitness improves.
Recovery becomes just as important as training volume. Sleep quality, post-run nutrition, and rest days all start to matter more as fatigue accumulates. Strength training shouldn’t disappear either. Even short, maintenance-focused sessions help keep tissues strong as running load increases.
This is also the time to practise fuelling and hydration during longer runs. What you eat, when you drink, and how your body responds should be familiar well before race day.
Month 3: sharpen, then absorb
In the final phase, the work is largely done. The focus shifts from building fitness to protecting it.
Long runs stop getting longer. Volume begins to stabilise, then gradually reduce. Any faster running becomes more race-specific and controlled, rather than hard for the sake of it.
This is where runners are often tempted to “squeeze in” extra sessions out of panic. More often than not, that’s when niggles appear. Don’t worry, your fitness won’t disappear overnight, but fatigue can linger if it’s not managed properly.
Recovery needs to take centre stage. Sleep, hydration, and fuelling are all vital. Don’t introduce anything new into your routine. Your shoes, nutrition, pacing, and routines should all feel familiar.
By race day, the goal isn’t to feel exhausted but accomplished. You want to arrive healthy, confident, and ready to run, not stressing over whether you’ve done too much or too little. Just relax and enjoy the experience. Get a few oggy oggy oggy’s in there!
The key with everything in this three-month plan is doing the right things at the right time, and giving your body the time and space to respond. Treat each aspect with the respect it deserves, and you’ll be in the best position possible to push off that start line in good health.
Maximise your marathon training with Up & Running
Marathon training can be daunting, but with the right training and footwear, everything is possible. Hopefully, the article above has helped with the former, and if you need help with the latter, you’re in the right place.
As the UK's largest independent running specialist, we have been helping runners for over 30 years. We stock shoes and clothes from the leading fitness brands, so you’ll find everything you need right here. Check out our Shoe Finder to find your next pair of shoes.
Or if you want to speak to a member of our team in person, or get a gait analysis, find your local branch with our store locator.
Shop our trending range today
For more insights, news, and advice, check out the Up & Running advice page.
How To Choose The Best Running Shoes | Choosing The Best Trail Shoes | Top Tips To Keep You Motivated
