How To Run 100 Miles: Essential Training Guide + Training Plan

There are few things more exciting than crossing a 100-mile race finish line.

The adrenaline, the fatigue, the mixed emotions.

I don’t know about you, but I had tears of joy running down my cheeks when I finished my first, and my second, and my third 100 miler. 

Every. Single. Time. That feeling never gets old.

In this article, I am going to give you 10 tips to help you train efficiently and successfully for your big 100 mile run!

We’ll also share our 100 mile training plans, free to download and customise!

Let’s get started! 

How to train for a 100 mile race

#1 Be Prepared to Put in the Time

Before taking the plunge and signing up for your 100-mile race, be sure you can commit enough time to your training.

The last thing you want is for your training to become a chore or an unwanted obligation that leaves you stressed out and unhappy.

How much time are we taking, exactly?


As we work through all of the important factors that need to be taken into consideration when training for a 100 miler, we will get a better idea of just how much time needs to be dedicated to this great feat. 

It isn’t just running time that needs to be taken into account, but also stretching, weight training, self-care, rest, eating and mental health.

#2 Choose Your Training Plan

No matter what your goal is, whether it be running your first 100-miler, trying to improve a previous time, or competing, you will need a detailed training plan that will ensure success. 

The total running-time commitment will vary, depending on your specific goal. However, our 100-mile training plans are all 6 months in length, no matter what your level, assuming you already have a solid running base. If not, the total length of the training plan would need to extend.

Let’s get an idea of our running time commitment for each type of goal.

First 100 miler: 4-5 days a week 

Improver 100 miler: 5 days a week 

Competition: 6 days a week 

As for time commitment, this is just the tip of the iceberg.

How to train for a 100 mile race

What kind of training does a 100 mile plan include?

Mileage, and lots of it

Whether you are running your first, or are a 100-mile veteran, time on your feet, in general, is imperative.

This is why you need to ensure you have enough free time in your schedule to train properly. On race day, you are going to be out there for the entirety of a day, most likely more, so you’ve got to put in the time.

Mileage will depend on your specific goal, so take a look at our different 100 miler training plans to get a better idea of how much weekly mileage you will need to put in.

(scroll to the end of this article for access to our free, customizable 100-mile training plans).


Most of your weekly mileage will be at a comfortable, easy to hold conversation pace, also known as, long slow distance, or “LSD” runs.

80-90% of your training runs will be at this pace. So get ready to rally up some friends to keep you company, or put together some playlists or audiobooks to keep you entertained! 

You may work in one speed session a week to improve your running economy and your base running speed, but for the most part, prepare yourself for long hours of trotting about.

Cross Training

When training for any sort of event, you want to focus most of your time practicing the actual sport you will be competing in, in our case running. However, if you are unable to run the number of days in your plan, you can add in some cross training such as biking, elliptical, skiing, or rowing. 

I do suggest you limit these sessions and try to get out there on the trails and pavement as much as possible. However, cross-training could come in handy as an alternative if you are battling any sort of injury during your training period.

Related: The Bear 100: 13 Lessons Learned From A 100-mile Ultra

100 mile training plan

Long Runs

This is where you will spend the majority of your training time, so clear out those weekends for the next 6 months, because you are going to be busy

As mentioned, these runs should be done at a very easy pace. When you finish each long run, you shouldn’t feel depleted or overtired, but as though you could have continued to keep running. 

Also, remember that every long run should be taken advantage of as a race simulation. Practice everything you plan to do, as you plan to do it during these runs.

 Train in similar weather and terrain that you will find at your race, practice your hydration and nutrition strategies, even wear the same clothing you plan on using. Every aspect should be taken into consideration and well-rehearsed so that you can  be as prepared and comfortable as possible for the big day.

Related: Why I’m Running 100 Miles

How to train for a 100 mile race

Back to Backs

Speaking of long runs, and when I mean runs, plural, I’m not just referring to all of the long runs throughout the training process. I also mean there is more than one long run per week.

There are two per week, usually scheduled on Saturdays and Sundays. 

These are the famous “back to backs” everyone talks about. They are a sure-fire way of getting used to running on tired legs

You’ll definitely need to build up a tolerance for that for race day! 

Contrary to popular belief, your long runs shouldn’t be extra-long and burn you out or bring you to a point where you can’t recover properly. Instead of piling on close to your total mileage in one or two days, you’ll split them up throughout your week, taking extra advantage of the weekends, so you can still rack up the miles, but in a much safer way

Don’t worry, you will be prepared if you follow your plan to a T.

It may seem like low mileage, but you’d be surprised what the body achieves on race day. There is always doubt going into your first 100 miler, because you think there is no way you could possibly run double or even more than your peak week long runs, but you will get to that finish line, I promise!

How to train for a 100 mile race

#3 Plan Your Peak Week

This should be scheduled in your training plan 3-4 weeks before your race. You’ll want to peak, and then have plenty of time to taper off before the race to be sure you are rested up.

You won’t lose precious endurance or fitness during your taper, but be able to rest up and get to the race strong and recovered. 

My favorite way to peak for a 100 mile race is choosing a race 4 weeks out. 

If there happens to be an 80100k race 4 weeks before your 100 miler, sign up for it!

You can enjoy your long run with lots of other runners and have assistance along the way. It will be much easier logistically than trying to organize such a long run on your own. 

It is important, however, not to get competitive out there. You don’t want to risk a burn-out after all the work you have put in.

#4 Study The Course

Get to know what types of terrain and vertical gain your race has, and train for those specific details. Find places where you can replicate parts of the race so you begin to feel more and more comfortable with every long run. 

Your training needs to match your race. If your race is full of long steep hills, hiking and using hiking poles should be a staple in your long runs.

If your race has a lot of flat, gravel road, you will want to practice running without a lot of walk breaks to simulate the real deal.

#5 Run At Night

Unless you are a speed demon and have run plenty of 100 miler races before, you are going to run in the dark at some point in your race. Do not leave this until the day of the race to to figure out.

You want to work night runs into your training plan so that you can get used to running in the dark. It’s not as easy a feat to dodge obstacles and jump over roots in the pitch black of night as it is on a bright sunny day. 

Fire up that headlamp and get out of the trails. You will also want to learn how your headlamp works, how to adjust the stream of light so it illuminates the trail ahead properly, and even how to change the batteries in the dark.

You will be happy you practiced this beforehand so it doesn’t feel as intimidating the night of. 

The dark won’t be the only obstacle for night running but running over-tired and on zero sleep. Try a really late run so that you can feel what it will be like to run physically and mentally tired while tackling trail obstacles all at the same time. This will be a valuable experience for the day of the race.

How to train for a 100 mile race

#6 Hit The Gym

Another piece of your training that I can not stress enough is the significance of strength training.

I always mention the importance of hitting the gym for all types of running goals, but only because I truly feel it transformed me personally as a runner. There is no more important race than a 100 miler where that extra strength and endurance becomes crucial. 

Your legs are going to want to fail at different points throughout the race, but the stronger they are, the longer they will hold on.

It’s not just your legs you need to focus on at the gym but your back and core as well. After carrying your race vest full of food, hydration, headlamps, batteries, clothes, hiking poles (and the list goes on and on), it will inevitably take a toll on your body. 

So get a head start and strengthen those muscles. You’ll be really glad you did when you hit mile 80.

Read our complete Weightlifting Guide For Runners

How to train for a 100 mile race

#7 Train Your Brain

To run a 100-mile race you need to not only be physically prepared, but also mentally prepared. They say 50% of 100 milers are mental, and guess what? 

They aren’t kidding. 

You need to be able to fight against your brain telling you to stop over and over again. Don’t give in to the negative thoughts of why you decided to do this in the first place, and forge ahead. We can not let our mind beat us and force us into an unnecessary DNF

So during your long runs, test these tips out.


Use mantras to help keep you going during long runs and on race day. Think positive thoughts and smile, it will help you through those tough moments. 

Here are a few to get you started:

  • “This too shall pass”
  • “Strong, confident, relaxed”
  • “I can do this”
How to train for a 100 mile race

Count Steps

I count my steps in bouts of thirty, or sometimes one hundred. I simply count each step until I reach that designated number and then start again. It really helps occupy my mind and keep me focused on something other than the negative thoughts. 

Distract yourself with what’s around you and enjoy gorgeous Mother Nature. You can also propose mini-goals during training such as reaching specific landmarks and playing around with Fartlek runs which is “speed play” at your discretion.

#8 Focus on Self-Care

You are going to be beating your body up quite a bit during these months, so you need to pamper it as you go so nothing breaks along the way.


Yes, we all dread it, but we need to dedicate these few precious minutes after workouts and long runs to stretch out our muscles. This will help your recover for the next day and prevent injuries.

Focus on stretching out your legs, hamstrings, quads, calves and glutes.


It’s very comical when non-runners hear you are going for your “massage” again, and tease you for indulging yourself. Little do they know…it hurts, and a lot! 

Ideally, a massage every other week would keep you in tip top shape. Try and schedule massages for the afternoon or evening before your rest day. They can leave you as beat up as if you had done a speed workout.

How to train for a 100 mile race

Physical Therapy

If something begins to bother you during your training, don’t wait until it’s too late to see a physical therapist. It’s most likely muscle tightness and a sports massage will alleviate the problem. However, you want to be sure it’s nothing else that will hinder your training. 

Don’t wait, make an appointment just as you begin to feel any pain that is out of the ordinary.


Your feet will be well-trained by the wear and tear of the miles and miles you will be putting in, so take care of them. Get a pedicure or give yourself one on a regular basis.

Hydrate your feet with lotion, keep nails short, and file down calluses so they don’t get too deep.

#9 Train Your Race Strategy

Know your race details. I can’t stress enough how important it is to know what you are getting yourself into so you can be as well-prepared as possible for race day.


Be familiar with the weather you will encounter on race day and plan your hydration accordingly. Take a sweat test to figure out how much liquid you lose per hour, and try to consume 80% of that amount during your long runs

Also, choose specific hydration products that will work for you and practice using them consistently. You want to be sure they sit well in your stomach and won’t give you a problem on the big day.

How to train for a 100 mile race


Just as you need to practice your hydration, you need to practice your nutrition routine.

Trial and error with food and sports supplements is the only way to figure out what works. Calculate how much and how often you need to consume calories and carbohydrates according to your weight. You can use this equation to get a general idea of what you need:

Weight in kilos = carbs per hour


Before each long run, try out different pre-run fueling to see what works best for you. Is it a banana? Toast and honey? Oatmeal? Try out a bunch of different options, and track how you feel on each run.


This strategy is one of the most challenging to figure out. First, you need to try out a variety of different energy products, and also incorporate solid, “real” food. You are going to be running for most likely an ENTIRE day, if not more depending on the race, so you’re going to get really hungry. 

Try peanut butter and jelly sandwiches, cookies, chips, nuts, anything you think would work for you. The race may even let you know in advance what they will have at the aid stations, so you could give some of those foods a try and see how you feel. 

Training your body to eat solid foods while running is not an easy task, and having to force down calories when you no longer want to, is a challenge in itself and must be trained.


Part of your training also includes your post-long run and workout recovery. Find a recovery drink or protein that works for you, and try to consume it within 30 minutes of ending your workout. 

How to train for a 100 mile race

General Nutrition

You’ll be running more than ever during these six months, so fueling your body on and off the track is crucial.

Train yourself to eat healthy, substantial meals and snacks on a consistent basis. If you need someone to get you on track, see a sports nutritionist! Tell them about your crazy goal and they can set you up with a helpful plan.

#10 Organize Your Schedule

It’s very important to schedule each piece of your training into your calendar to make sure you don’t forget any tiny detail. 

Here’s a checklist, so grab your calendar, and let’s get planning!

  • Runs
  • Nutritionist appointments
  • Massages 
  • Physical Therapy
  • Sleep

By slotting out the time you need for each piece of your training, you will alleviate a lot of stress. Plan each month in advance and check your calendar each evening to know what you need to get ready for the following day. 

How to train for a 100 mile race

I know this is an overwhelming amount of information but running a 100-miler is an overwhelming goal, and you need to be as prepared as possible to be successful. 

The most important thing is that you enjoy the process. This is an amazing challenge you have set for yourself and you should already be proud for even taking this into consideration. Now, let’s make that dream a reality, and let’s get training! 


How To Run 100 Miles: Essential Training Guide + Training Plan 1

100 Mile Ultra Training Plan – Just Finish

This 100 Mile Ultramarathon training plan is designed for runners who are simply looking to comfortably complete their event.

With 6 months to prepare, we focus on very gradually increasing the weekly mileage at a manageable rate, so you don’t end up burning out.

Ideally you should be able to run 3-5 miles without stopping before you begin this plan, but you can choose to adopt a run/walk strategy too!

Who is it for?:  First-time ultramarathon runners, runners who want to complete an ultra with limited time to train each week, runners who just want to focus on comfortably reaching the finish line.

How Long?: Six months, or 24 weeks.  If your only objective is to complete your ultramarathon comfortably, and you have six months (or more) to prepare, this is the plan for you!

The plan includes some optional speed work, but this is only if you’re comfortable and can squeeze it in – the objective is to get the required mileage in.   It includes 3 mid-week runs, to be performed at a comfortable pace, and one long-slow run each weekend to build your max mileage.   The plan includes one cross-training day per week and two rest days. 

How To Run 100 Miles: Essential Training Guide + Training Plan 2

100 Mile Ultra Training Plan – Improver

This 100 Mile Ultramarathon training plan is designed for runners who are looking to challenge themselves – perhaps to set a new PR, or simply to run their best race.

Designed to be run over 6 months, the plan features one speed day per week, and more mileage than the ‘Just Finish’ plan – so you’ll have a stronger base and better running economy.

Who is it for?: Established runners who want to challenge themselves, and perhaps set a new PR.

If you’ve already run a distance event such as a marathon and want to improve your performance, check out these training plans.  

Our Improver training plans balance training and miles with rest days and (optional) speed work; only include the speed work if you want to improve your base running speed.

If you’ve got some distance running experience, and want to push yourself a little, this is the training plan for you.

How Long?: Six months, or 24 weeks. 

How To Run 100 Miles: Essential Training Guide + Training Plan 3

100 Mile Ultra Training Plan – Compete

This 100 Mile Ultramarathon training plan is for experienced runners looking to push themselves!

It features six days of training per week, including two days of speed work, long runs, and recovery runs (which get gradually longer in length).

Who is it for?: Experienced runners who want to set a new PR and perform well competitively.  

If you’re planning to race and gain a good position, this is the plan for you.

Our Compete plans feature the most intense training regimes – there’s a lot of miles in there, different challenging workouts (speed-work), and typically only one rest day per week.

You should only attempt the Compete plan if you are starting from a solid running base, and have the time commitment and drive to really challenge yourself.

How Long?: Six months, or 24 weeks.  

How to train for a 100 mile race
Photo of author
Katelyn is an experienced ultra-marathoner and outdoor enthusiast with a passion for the trails. In the running community, she is known for her ear-to-ear smile, even under the toughest racing conditions. She is a UESCA-certified running coach and loves sharing her knowledge and experience to help people reach their goals and become the best runners they can be. Her biggest passion is to motivate others to hit the trails or road alongside her, have a blast, and run for fun!

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