Inspired to write this by watching numerous top athletes such as Courtney Dauwalter complete their third successful 100 mile attempt in a year, and then witnessing some of our local club athletes run and complete the same, we decided to look at what you need to run 100 miles. Many of you may have found this article while Googling “100-mile training plans” and you will find some sound advice here but, as qualified running coaches, what we will say is this is not a plan designed for one specific individual. Instead, it is aimed at giving you food for thought and detailing what is involved in running this sort of distance. If you are planning 100 mile ultramarathon then grab yourself a cuppa and read on.

What you need to consider before committing to 100 miles

This is an overview of things to consider if you are planning 100 mile ultramarathon – a rough guide accompanied by some solid advice. If you want a specific plan, we recommend you seek advice from a coach who can take into account several factors that are unique to each individual. We will look at the elements you need to consider before signing up including:

  • Lifestyle and job
  • Daily commitments – family, work etc.
  • The amount of time you have to train
  • The type of terrain you will be training on
  • The sort of training you should do
  • Cross training
  • The gear you will need
  • Fuelling for this distance
  • The type of training you will need to undertake


The type of lifestyle you have is key when you are planning a 100 mile ultra. Is your job sedentary or active? Do you sit at a desk all day or do you have a very busy and active day job? If you are always on the go, you may find you need to run fewer weekly miles than someone who is not very active. for those who don’t have a physical job, incorporating some element of strength training is a good idea. I often find that when I start pushing out the longer miles, I get shoulder pain, back pain from climbing and that some strength and conditioning training is required to help me strengthen my core but then I am sat at a desk all day. My other half has an active job and doesn’t have to do so much by way of cross-training to get the results. Weights, core training exercises, cycling, walking, hiking, and swimming are all forms of training that will complement your running and give the muscles you use when running a rest too. 

How much time do you have?

How much time can you commit to a training plan?  This will depend on family, job, and commitments – how much time do you have to train for 100 mile ultramarathon? If you haven’t got time to fit more than a couple of runs in a week, you are going to struggle to get the necessary training in. Ideally, you need 4 solid sessions a week, one of which is your long run which can take anywhere between 3-6 hours depending on your pace, terrain etc.

What type of terrain is the course?

Most 100 milers tend to be off-road with a considerable amount of elevation. You need to be prepared for this. Running a few small local hills isn’t going to prepare you for some of the more serious climbs. If you struggle to get that kind of terrain by running from your front door, you need to consider traveling to find a more suitable training ground.

Remember – TRAIN FOR THE RACE YOU ARE RUNNING. This means not training multiple hills for a flat race or vice versa.

There are some great 100 mile races – some of them have fierce reputations, some of them are world-famous and others are local smaller events put on by local clubs. If you decide to have a crack at a different continent, you are also going to have to consider the weather, the climate, the navigation skills required, and the type of wildlife you might encounter. Imagine being from the deepest darkest Somerset, England and turning up unprepared to take on a race in Colorado for example! You have to be realistic about the conditions you train in and the race you are training for. Not to mention jet lag and other factors of traveling so far before a race.

Pre Race prep

You can put in the hard yards but you are not going to run the distance in training. In fact, you may undertake a shorter distance as your longest training run – 40/50 miles maybe but you aren’t going to reach the dizzy heights of 100 miles in training. This means there are eventualities that you can’t prepare for. How will your body hold up to 100 miles? Feet, legs, toes, chest… it’s difficult to know what, if something, is going to let you down. Are you going to get riddled with blisters with wet feet after 50 miles or will you suffer from cramps?

You can do as much preparation as possible but you will never be ultimately prepared. You won’t know how your body and mind hold up until you are faced with those latter miles when you are tired, carb-depleted, worn out, and emotionally and physically drained. All you can do is give yourself every fighting chance.

Planning your gear

We have been following Vernon Kay on BBC Radio 2 as he prepares to take on his ultra ultra-marathon over the next few days for Children in Need and had to chuckle this morning when he discussed with Zoe Ball the gear he had packed. Now he’s not doing 100 miles – he’s doing 115 and he is doing it over 4 days (usually you will do 100 in one go with fuel and comfort breaks). Anyway, he announced that he had 20 pairs of running shoes and some hiking boots to see him over the fells in grueling conditions. He also needs wet weather gear, regular changes of kit, socks, nipple chafing balm – you name it, he’s gonna need it. Now, when you do a 50, the chances are you carry it all with you. We certainly have done but when you are doing 100, you often have people crewing for you that can carry your stuff and have it ready for you at the various checkpoints. You should consider having a bag for each checkpoint with what you are going to need.

We have said it before and we will say it again – practice running in the gear you are going to run in on the day. You don’t want to discover that new socks give you blisters or don’t hold the water well. You don’t want chafing from shorts that are longer/shorter. You don’t want to find that your ultramarathon vest rubs in the wrong places or that your watch won’t hold charge for that long. You need to prepare and be familiar with the gear you will use on the day.

Trail Running Shoes

This is the element of your gear that is going to do most of the work – it will be subjected to the biggest amount of battering as you take eleventy billion steps in them. Wear them in and wear them in well. If you feel you are going to need more than one pair of trail running shoes, make sure they are worn in too. Perhaps you will rotate the same make and model but have 2 or 3 pairs. Don’t rely on them fitting the same if you haven’t worn them. Make sure you put about 50 miles into each of the shoes you plan on wearing. You may think that one pair will be enough – trust us – if they get wet, you want to consider a change of shoes and socks. We know someone who just had to pull out of a race at 93 miles after his feet took a pounding and spent too much time getting wet. His feedback was “More foot prep required for next time!”

trail running shoes

Don’t leave it too close to the event to choose the shoes you will wear – if you have a familiar brand that works over long distances – stick with them – otherwise, hurry up and choose the shoes that you are going to rely on to see you through the distance. We are big fans of Hoka Speedgoat and Altra Lone Peak 7 for long distances but this isn’t to say that they are for everyone.

Choosing your crew

Now we just mentioned crew but it’s important to plan who is going to be supporting you. the darkest times are literally the darkest times – the middle of the night when it’s pitch black and it’s just you and your head torch battling potential hallucinations, fears, and noises in the night. If you can have someone running with you then that’s a good idea but you certainly want to have people at your checkpoints making sure they supervise your fuel intake, making sure you change your socks and that you are comfortable before you go on again. Once you have put some serious miles down, being in charge of your own fuelling and comfort breaks is not the best idea. Have someone to look after this for you.

Get yourself a 100 mile marathon training plan

We could sit here and say do x amount of miles per week with back to back runs, long runs of 30 miles, 4 sessions a week, this amount of elevation but every individual will have different needs so here are our basic rules. For a more detailed plan, we recommend seeking advice from an expert – someone experienced in either coaching or running ultra marathons of this distance.

There are plans online that you can look at to get some inspiration but you have to realize that everyone is different and what you need will be different to someone else. We like this 100 mile training plan from inov-8. It is only 18 weeks though so would assume that you are at some sort of decent base mileage already.

The snippet below shows the first four weeks of the plan. If you click the link above, you will see that it is a full 18 week plan.

100 mile ultra plan

Build endurance

All training plans are about building endurance. Think back to your first half marathon and how you started at 5 miles and built up to 10 before undertaking 13.1. Some don’t even do the distance before they race it. You need to build up the miles and the frequency of your runs. Do it gradually and don’t try and do 30 miles on a Sunday in your first week of the plan – you will get injured – build it up slowly and have cut back weeks at regular intervals to give your body time to recover. Train over a 6 month period so that you aren’t trying to cram the miles into a short training block.

Try back to back runs

We are big advocates of this and always try and do our weekends back-to-back. For a 50-mile ultra that usually looks like 10 on a Saturday and 20 on a Sunday for example. You need to run on tired legs to get familiar with running on tired legs. I often do a hard session on a Saturday followed by long slow miles on a Sunday.

Incorporate the elevation

We have written a guide to training for elevation. It’s a good read and will help you include the necessary hill training into your plan. Combining long miles with hills is often a great training exercise but you can try hill reps too so that you can get used to that continual elevation. Hiking is also a good idea – it’s highly likely that you won’t be running the hills in a 100 miler – instead, you will be hiking them so get out on the hills and practice your hiking.


Perhaps one of the most important elements is the fuelling both throughout your training and during the race itself. You need to ensure that you are eating the diet worthy of an athlete and that you are putting the right stuff into your body. It’s like putting fuel in a car – you have to put the right stuff in to get the best performance.

You also need a fuelling plan for the race itself – not just a training plan. What will you eat, how often, what will you take in your backpack, what will you have at the checkpoints, at what point will you start to feel so nauseous you can’t eat anymore and what can you use to keep yourself fuelled at this point? What fluid will you take on board – water, Tailwind, electrolytes etc. You can’t just suddenly eat this food on race day either – you need to train with these foods in your system so that you know they don’t suddenly provoke an attack of a dodgy belly!

Listen to your body

Training is hard for any distance but planning a 100-mile ultra marathon is a big ask of yourself. When training, be sure to get the proper recovery between runs, and if you find it getting tough, it’s a good idea to take a break. It won’t hurt to put your feet up for a couple of days and not panic about the miles you are missing. Sometimes the recovery will do you more good than the miles – especially when you run this risk of injury or exhaustion.

Expect the unexpected

It’s fair to say that in any race – half marathon, marathon or ultra you can expect things to go wrong but when it is such a big difference there are so many things that can go wrong. That’s not to say that it will but prepare as much as you can for what you are asking of your body and mind and enjoy the training as much as the event itself. You are going to spend a lot of time putting in the hard yards so it is important to get as much out of it as you can.