Running a Marathon Without Training: Potential Risks + Essential Training Blocks

If you’re considering running a marathon without training, you may have your reasons. 

Maybe your work schedule got busy and you didn’t have time to get through your marathon training plan

Maybe you got sick and found it hard to stay motivated after you recovered. 

Maybe your half marathon was canceled so you didn’t bother training, but now your scheduled marathon is coming up and you’re wondering if it isn’t too late to give it a shot. 

All of these are common reasons and happen to the best. 

The best advice I can give you is don’t do it. Come back and do another marathon once you’ve had time to train properly.

Don’t run a marathon without training! There are so many risks and negative effects involved. In the end, you’ll thank yourself for postponing your marathon until you’ve adequately trained for it. 

All those muscles worked during running will thank you for it too. 

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What Are the Consequences of Running a Marathon Without Training?

The list of risks is long, but these risks of running a marathon without training can be categorized into 2 groups:

  • Your physical health will suffer
  • Your running will suffer long-term.

You’ll also very likely have a pretty miserable marathon experience . . . you’re almost destined to hit the wall.

Let’s get deeper into what’s gonna happen…

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1. Your Physical Health Will Suffer

Dr. Dylann Craig, physical therapist and RRCA certified running coach at Impact Physical Therapy, has seen way too many patients as a result of runners being unprepared for marathon training. 

“Running a marathon is a physically demanding task and typically requires a structured training period. This training period is heavily dependent on how seasoned a runner you are.

A beginner runner, someone who has been running less than a year or less than 20-25 miles per week, will typically require about four months of training. Experienced runners can get away with less depending on their current cardiovascular capacity and previous running history.

I typically recommend that a new runner should average a minimum of 30 – 35 miles weekly for about 6 weeks prior to entering a race. If you can’t reach that number weekly, you should continue to increase your capacity prior to beginning a formal marathon training plan.

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When clients attempt to run half or running a marathon without training properly, they typically land in my clinic with some sort of injury. The most common distance running injuries I see are:

  • ITB syndrome and patellofemoral syndrome (runners knee) at the knee

These injuries typically land the runner in a vicious cycle that is difficult to break – they will improve and immediately attempt to increase their mileage quickly to ‘make up for lost time’ which may lead to chronic pain and overuse related stress fractures.”

Running coach Josh Muskin has also encountered some clients who were unprepared for a marathon. He adds to the warnings against tackling the marathon with no training. 

“‘Elite’ recreational athletes barely break the 3-hour mark, which means for most (especially those with 0 training), it’ll be 4, 5, maybe even 6 hours on your feet. 

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This Harvard article notes that upwards of 75% of runners are injured each year. And those are runners, not people deciding to just run 26.2 miles!

The most common injury cause? Overuse, which is exactly what you’re doing running a marathon without training.”

He points out one of the most severe risks involved in this lack of preparedness: Rhabdomyolysis. 

“On the most severe end, rhabdomyolysis (Rhabdo) is caused when muscles break down (and die) and release their contents into the bloodstream. This can lead to serious complications such as renal kidney failure, and potentially death.”

2. Your Running Will Suffer Long-Term

running a marathon without training

When you run a marathon without training much, the extreme physical issues you suffer (not to mention being so sore you can barely move and the fatigue you’ll feel for days afterward) are likely to leave a sour taste in your mouth when it comes to running. 

In fact, many runners who attempt a marathon without doing their training proper justice quite running for good because the experience is such a negative one. 

Running a marathon can be exciting, invigorating, and empowering when you’ve trained right. Sure, it will still be challenging, you’ll still have to push yourself physically and mentally, but you will have fun and be thrilled about the process. 

Without training, it could be your first and last marathon, causing you to miss out on the joy, pleasure, and health benefits of running. 

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Hitting the Wall – The Risk of Running a Marathon Without Training

When you forego a solid training plan, you may actually suffer before you’ve even finished the marathon you’re running. It’s called the hitting the wall. 

There comes a point in every runner’s journey where they hit that dreaded dead end. You go from running with confidence and strength to feeling depleted. 

Suddenly, you’re void of energy and motivation. You’re seriously doubting your ability to finish the race. You have no bounce left in your muscles. Even after slowing your pace, you’re still struggling to keep going. 

What causes hitting the wall?

For most people, this happens somewhere between miles 18 and 20. As you’re running, your body’s stores of glycogen deplete. Your legs all of a sudden feel week. You are unable to carry on with your run. 

This can happen to anyone, even those who have trained properly. But for those who have trained ahead of time, they can bounce back by taking a brief rest, a long drink of water, and having a bit of protein or sugar. 

Without the proper training, you may not be able to recover so quickly and might not be able to finish the race. 

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Building Blocks of a Good Marathon Training Plan

Now that you’re convinced against running a marathon without training, it’s time to focus on setting yourself up with the right training foundation to get the most out of your plan. 

Here are the essential steps you need to prepare for your marathon:

  • Gradually increase your mileage week by week to increase your endurance. 
  • Work on your running form to optimize your training and prevent injury. 
  • Incorporate a variety of training into your plan: cross-training like cycling and swimming and muscle-building like bodyweight exercises or moderate weight lifting. 

Muskin provides some of his essential recommendations that he gives his own clients. 

Jump rope. Can you jump rope 100 times without excessive soreness? If not, maybe start doing 5-10 sets of 10-15 jump rope a day. That key ‘bounce’ of the leg is a significant movement in running. Doing this can help prepare your body before hopping into a plan. 

Starting point analysis – doing some self-reflection about where you actually are. Can you casually run a 5k? (related: average 5k times) Can you complete a single mile? An honest answer to your starting point will help you find a program that starts where you are currently. If you can’t yet run a 5k and week 1 of a marathon plan says to run 10k/day – well, that’s probably not the place to start. 

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When choosing a plan, here are the key things to be on the lookout for: 

  • Does it start where your current fitness is? – Similar to above, if you’ve not yet mastered running a mile, don’t start with a 25-mile week. Find a couch to marathon plan or similar that talks about using the Run Walk Marathon Training method, and how to work up to ‘running’ through an entire workout.
  • Does it peak around 20 miles? – Any solid plan should cap out between 18-22 miles on the longest long run. If you find a plan that never runs more than 14-16, you may be in for a rude awakening on race day. Similarly, if you find one that requires you to run 24-26, and you’re not accustomed to running that far, it puts you at unnecessary risk for injury. That 20-mile run is both great physical training, but a mental confidence booster too.

Can You Walk a Marathon Without Training?

You may find yourself in a situation where you’ve trained moderately, but once you get into the marathon, you realize the training was not adequate. At that point, you might be able to adjust your pace and finish the marathon by walking. 

This will create far less impact and stress on your body and can be a good alternative to quitting. 

However, even walking a marathon is rough on the feet, joints, ankles, and knees. If you haven’t walked at least 20 miles in one go in the past month or so, we don’t recommend walking a marathon without training either. 

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The best way to go is ultimately to cancel that race you’ve signed up for next week, download one of our free training plans, and hit the trail on the next one with the proper preparation. 

Mia Kercher

Mia Kercher

Mia Kercher is a hiker, cyclist, and runner. After finishing her first marathon in 2013, she continued the sport but found a new passion in trail running. She now explores the glorious mountains in Portland, Oregon where she works as co-founder of Evoke.

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