7 Mistakes You're Making with Your Marathon Mileage (and How to Fix Them)

So you've signed up for a marathon. Congrats! You're about to join a special club of people who voluntarily run 26.2 miles. Bold move.

But here's the thing. Between now and race day, there's a whole lot of mileage to cover. And how you handle that mileage? That's where things can go sideways fast.

Most runners don't fail because they're lazy. They fail because they're too eager. They pile on miles, skip rest days, and treat every run like it's a race. Sound familiar?

Let's break down the seven most common marathon mileage mistakes, and more importantly, how to fix them before they wreck your training (or your body).

Mistake #1: Starting at Too High a Mileage

You found a marathon training plan online. It looks legit. Week one says 35 miles. Only problem? You've been running 15 miles a week. Maybe 20 on a good week.

This is a recipe for disaster.

Your body isn't ready for that jump. Your muscles, tendons, and bones need time to adapt to increased stress. Skip that adaptation phase, and you're looking at shin splints, stress fractures, or worse.

The fix: Your training plan's starting mileage should be equal to, or no more than 10% higher than, your current weekly volume. If the plan demands more, spend a few weeks building up before you officially start. Think of it as a pre-training phase. Boring? Maybe. But your knees will thank you.

Mistake #2: Increasing Mileage Too Quickly

Week one: 30 miles. Week two: 45 miles. Week three: 60 miles.

See the problem?

Jumping your weekly volume like this is basically begging for an injury. Your cardiovascular system might adapt quickly, but your musculoskeletal system? Not so much. It takes time for bones, tendons, and ligaments to strengthen.

The fix: Gradual progression is your friend. A common rule of thumb is the 10% rule, don't increase your weekly mileage by more than 10% from one week to the next. Some coaches recommend even smaller jumps. The point is consistency. Steady, sustainable increases beat aggressive spikes every single time.

Mistake #3: Choosing a Training Plan That's Too Short

Here's a scenario. Your marathon is in 10 weeks. You find a 10-week plan. Perfect, right?

Not exactly.

A 10-week plan assumes you're already at a certain fitness level. If you're starting from scratch, or even from a moderate base, you're going to be rushing your fitness development. And rushing leads to shortcuts. Shortcuts lead to injuries. Injuries lead to DNS (Did Not Start).

The fix: Give yourself enough runway. Most marathon plans run 16 to 20 weeks for a reason. That time allows you to build a solid base, develop endurance, and strengthen the small stabilizing muscles that keep you injury-free. If your race is coming up fast and you're not ready, it might be worth choosing a later race. There's always another marathon. There's only one you.

Mistake #4: Running Easy Runs Too Fast

This one's sneaky. You head out for an easy run. You feel good. So you push the pace a little. Then a little more. Before you know it, your "easy" run is actually a tempo effort.

Here's the truth: easy runs aren't supposed to feel impressive. They're supposed to feel... easy.

When you run your easy miles too fast, you're burning energy that should be saved for recovery and harder workouts. You're also adding unnecessary stress to your body between key sessions.

The fix: Run by effort, not pace. A true easy run should be conversational. Like, actually able to chat with a friend without gasping for air. Some runners ditch the watch entirely on easy days. Others use heart rate monitors to stay honest. Whatever works for you, just slow down. Your PRs will come from nailing your hard workouts, not from crushing your recovery runs.

Mistake #5: Stacking Hard Workouts Back-to-Back

Monday: intervals. Tuesday: tempo run. Wednesday: hill repeats.

Sounds hardcore, right? It also sounds like a one-way ticket to overtraining.

More workouts don't automatically equal more fitness. Your body needs time to recover and adapt. That's when the magic happens, during rest, not during the workout itself.

The fix: Build recovery days into your schedule. After a hard session, follow up with an easy run or a rest day. Most well-designed training plans alternate hard and easy days for a reason. Trust the process. Lighter sessions aren't wasted days. They're investments in your next big effort.

Mistake #6: Trying to Make Up Missed Mileage Too Quickly

Life happens. You get sick. Work gets crazy. You miss a few runs.

So what do you do? Cram all those missed miles into one mega-long run at the end of the week?

Please don't.

When you compress missed mileage into fewer runs, you're not getting the same training effect. You're just overloading your body. And if you needed the rest in the first place, piling on extra miles is only going to dig you deeper into a hole.

The fix: If you miss a week or more of training, simply repeat that week the following week. Don't try to "catch up." Accept that some miles are gone and move forward. It's better to arrive at the start line slightly undertrained than injured or burned out.

Mistake #7: Adding Extra Intensity Beyond the Plan

You're feeling good. Really good. So you decide to push your intervals a little faster. Or turn your easy run into a progression run. Or skip that recovery week because you don't feel like you need it.

Bad idea.

Training plans are designed with intention. The easy days, the hard days, the cutback weeks: they all serve a purpose. When you add intensity, you're throwing off the balance. And that extra effort today? It might cost you three or four days of recovery tomorrow.

The fix: Follow the plan as written. Resist the urge to do more. Include cutback weeks every three to four weeks where you reduce volume and intensity. And listen to your body. If something feels off: if you're unusually tired, sore, or mentally drained: take an extra rest day. That's not weakness. That's smart training.

The Bottom Line

Marathon training is a long game. It's not about how hard you can push in a single week. It's about showing up consistently, week after week, without breaking down.

These seven mistakes? They're incredibly common. And they're all fixable.

Start where you are. Build gradually. Run your easy days easy. Respect recovery. And trust the plan.

Do those things, and you'll not only make it to the start line: you'll cross the finish line feeling strong.

Got questions about your training? We're here to help. Reach out to us anytime. And if you want more tips like this, check out the LOVE JOY RUN blog for everything from injury prevention to race day strategies.

Now get out there and run smart.