Hey guys, waaaay back in 2015 I ran my first 100k and wrote this article soon after (one of my earliest!). I’ve since run a bunch more ultras and become a running coach, so I’ve gone and updated the article a little with some tweaks and better info. Here is it: how I made the jump from 42k to 100k in a single event – Race To The Stones – with no specific training, and finished in under 12 hours . . .
Last July, I ran my first 100k ultramarathon – Race To The Stones, along the Ridgeway in South England. Despite not training specifically for the race, I completed the 100 kilometers (62.14 miles) without too much pain – and got to the finish line in 11hrs 39mins.
Having previously only run marathons, how did I manage to survive the step up to 100km?
Here’s my guide to making that leap to the world of ultrarunning!

Making The Leap To 100k – Signing Up For Race To The Stones
Like many people who have managed to complete a marathon, once my feet had recovered and I’d suppressed most of the ‘I’m-never-doing-this-again’ mid-race thoughts, I began to wonder what else I was capable of.
The same voice that pushed me to sign up for my first marathon was now nagging me to see what else was out there.
The idea of running something as long as a 100k race was daunting, and not particularly appealing – why would I want to try and run for that long? Surely that’s not good for your body? It’s just going to be endless hours of discomfort, right? Still, that same internal voice persisted in looking for a new challenge.
My friend Megan happened to mention she was running the Race To The Stones 100k through South England in a few months, and why don’t I join her? On a whim, I loaded up the race website and keyed in my details. I told myself that I wasn’t actually committing to the race, just penciling in my interest – I could easily pull out at any point.
As the race approached, Megan had to pull out due to a knee injury – it would have been the perfect excuse for me to pull out too. But instead, I quietly kept the race at the back of my mind, and as the summer approached I tentatively booked flights and hotels – I didn’t even tell any of my friends or family about the race, I was so apprehensive. All they knew was I was going to do some run outside London.
(As a disclaimer, I should mention I did run a couple of stage races in the 12 months before my first 100k – however I walked the majority of these, and the longest distance I’d covered on foot in one day was 77k – which I walked.)

The next thing I knew I was at Heathrow bus stop just before 05:00 am on race day, waiting for a bus to Oxford, dressed in my running gear. A couple of hours later, I was at the start line . . . completely oblivious as to how the day was going to unfold.
Then we were off.
So how did I finish the race in 11hrs 39mins when my recent training had just been a couple of 10k runs and a few weightlifting sessions per week?
- Related: My FREE 5-Day Ultrarunning Bootcamp

1. Ten Small Races – Divide Up The Route
For most of us, 100k is too far a distance to really comprehend covering by foot in one day. We’re used to training for a few hours at weekends, but nothing on this scale. The distance, and also stimulus along the way, can be overwhelming.
So don’t look at it like one long event: break it into 10 small ones.
Fortunately, at these events each checkpoint is roughly 10km apart, so these are your perfect bite-sized chunks. Every runner knows what a 10km feel like in their head, so just tell yourself you are doing a 10km run each time.
If it helps, mentally picture yourself running your familiar 10km route back home. Never think beyond the next checkpoint.
2. Focus On Exertion, Not Speed
In ultra-distance events, if you feel you’re pushing your legs hard then you’re probably going too fast.
I never push myself beyond a comfortable ‘conversational’ running pace in these long events, because I know I need to save my legs for the rest of the race. I sit at a steady 3-4 out of 10 in terms of rate of perceived exertion.
Maybe in the last stage I’ll start to dig deep, but otherwise don’t think you’ve got to hold a certain pace – let your comfort level dictate your running speed, not the other way around.
Related: The Best GPS Watches For Ultrarunning

3. Think Splits: Aim For An Even Pace
My goal in any race is even splits – this means a consistent speed throughout the race. If you see someone at a finish line that has just run on even splits, they’re usually fairly comfortable, smiling – they’ve just completed a race at their planned, consistent speed.
It’s inevitable that on longer races you slow down as your body gets tired; my first 50k took 5hrs 30mins, my second 50km took 6hrs 10mins – not perfect, but more consistent than almost every other runner.
Don’t fall into the trap of going too fast to start with, then suffering later on. If you stick to a comfortable pace and medium-exertion level, an even split should come naturally.
- Related: 10 Lessons I Learned From My First 100k, By Maria Andrews

4. Psychological Trick: Underestimate Your Pace
Here’s a psychological trick I play with myself, that seems to work (I’m weird) . . . at each checkpoint, I ask how far it is to the next checkpoint, then over-estimate how long it will take me to get there.
So if it’s 10km between checkpoints and I know I’ve been running strong, I know I should take about 60-70 minutes to get to the next checkpoint. But I’ll add in some fat, and tell myself I’ll take 80-90 minutes to get there.
This way each checkpoint comes in ‘early’ and you feel good. On ultra-distance runs, any little trick like this to give you a boost helps.
Related: Ultramarathon Training Runs Explained

5. Don’t Sit Down
I’ve learned that sitting down at checkpoints is dangerous, at least for me.
If I sit down when I’m tired, it takes a serious amount of willpower to get back up.
Instead, I try and zip through checkpoints – when I see one on the horizon, I neck my salt tablets and get my water bottles ready, then when I reachย the checkpointย I just fill up on water, grab snacks and keep moving. ย
If I am tired and need a breather, I’ll walk for 5-10 minutes after I’ve left the checkpoint – this gives me a chance to drink, have a gel, etc. As you get further into the race, the lactic acid builds up in your legs and the last thing you want to do is stop moving them!

6. Know Your Guts
From my stage races, I knew what my guts were capable of handling when out running in the heat for hours at a time.
I’m lucky, I can chug gels at a rate of one every hour without any adverse affects, and can snack all day too. I also know I can’t handle anything dense, like a Clif Bar or a proper meal while running.
But I learned this through testing before entering the 100km race – I didn’t try anything different on the day.
Related: Ultramarathon Nutrition Guide: What to eat before, during, after an Ultra

7. Schedule All Your Intakes
Gels, snacks, salts, water.
That’s all you’ve got to remember to take, yet it’s amazing how easy it is to get mixed up and forget to take something.
Your brain tends to get kinda fuzzy after a few hours out on the trails.
I typically use two things to schedule my intake – checkpoints, and the hour hand on my watch.
For gels, I’ll take one every hour, on the hour.
For salt tablets, I take one or two every checkpoint.
But everybody is different – so plan your schedule before the race starts and stick to it.
For water, I follow the rule of regular sips to stave off thirst, rather than drinking more than I feel like – your body always tells you what to take, if you can listen to it.

8. Prepare for boredom, but don’t drown it out
On Race To The Stones, I learned that monotony and boredom can be an issue for me on really long runs, especially when running by myself.
When preparing for the race, I loaded up on podcasts and audiobooks, and decided to listen to something from around checkpoint 2 – thinking that it would be good to stay distracted and keep my mind occupied during a long, long event.
The truth was that the stuff I was listening to made me distracted and bored, and made me feel disconnected from the race – so in future I’m going to use my iPod a lot less.

9. Be humble
100k is a huge stretch, and you never know what’s going to happen. Old injuries can flare up, new injuries can appear, heat, exhaustion and just about anything else can get the better of you – so never turn up to one of these with an assumption as to how you are going to perform.
It’s nice to get a good time, but mentally prepare yourself for the what-if of a DNF. Staying within my limits is what got me to the finish line comfortably, and humbly, pleased I was lucky enough to get through the race without major issues.

Your first 100km event is always going to be a mammoth undertaking, but mental preparation and having a strategy in place is key for keeping you in the game.
Check out our Essential Guide to Running Your First 100km, with a training plan โ

Training Plans For 100k
OK the big one – I turned up to Race To The Stones race with no specific training, I was just running a couple of times a week with friends if I found the time, and was going to the gym regularly.
My gym sessions, meanwhile, covered my whole body – including legs And although this wasn’t a specific training programme, this strength is really important when it comes to the endurance required to run 100km in one shot.
While my training seemed haphazard and a bit aimless, the truth is I was following the simple rule of working out for 1 hour per day, be it cardio or weight training. This, combined with my existing base of running fitness, is what got me to the finish line in good condition.
In subsequent 100k races, I’ve finished in podium positions and cut over an hour off my PR by following a structured training plan.
I’ve gone on to develop 3 different 100k training plans aimed at different ability levels, which have been downloaded over 30,000 times.
Check them out! They’re free to download in both PDF and Google Sheets / MS Excel format:
100k Ultramarathon Just Finish Training Plan
Our Just Finish training plans are for runners who simply want to complete their event. If you donโt want to spend all your free time training, and have no specific finishing time in mind, this is the plan for you.
Our Just Finish training plans usually have more rest days and very little speed work (if any); theyโre designed to condition your body to complete the distance, but not to win any medals.
The Just Finish training plans are ideal for completing your first event, or for runners with busy lives!
100k Ultramarathon Improver Training Plan
Our Improver training plans are for established runners who want to challenge themselves, and perhaps set a new PR.
If youโve 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 youโve got some distance running experience, and want to push yourself a little, this is the training plan for you.
100k Ultramarathon Compete Training Plan
Our Compete training plans are designed for experienced runners who want to challenge themselves, set a new PR, and perform well competitively.
If youโre planning to race and gain a good position, this is the plan for you.
Our Compete plans feature the most intense training regimes โ thereโs 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.

Here are some further resources I think you’ll find useful in preparing for your 1st 100k:
Take Your Training Further With The Ultra Runner’s Playbook
If you’re looking for a deep-dive into the world of ultra-running, then check out my Ultra Runner’s Playbook!
The Playbook is my premium course for anyone looking for a complete online ultramarathon coaching solution…
With over 5hrs of video content and a ton of downloadable material, we cover:
- Detailed daily training plans for ultramarathons, based on running ability
๏ปฟ - Ultra training modalities broken down; in other words, how to train smart
๏ปฟ - Ultra running strategies for success
๏ปฟ - Expert videos and guides on . . .
๏ปฟ- Having an ultrarunning mindset
๏ปฟ - Balancing training with your other time commitments
๏ปฟ - Maintaining motivation throughout your ultra journey
๏ปฟ
- Having an ultrarunning mindset
- How to become an injury-free ultra-runner
๏ปฟ - Strength and resistance training for improving performance and reducing injury
๏ปฟ - Fuelling and nutrition for ultrarunners
๏ปฟ - How to achieve your ultramarathon goals
๏ปฟ - And plenty more expert interviews, articles, and guides!

What salt tablets did you use?
Hello Craig,
I use saltstick tablets. They’re simply regular salt in capsule form.
https://www.amazon.com/SaltStick-Electrolyte-Replacement-Capsules-bottle/dp/B002IY96B0/ref=pd_lpo_vtph_121_bs_t_1?_encoding=UTF8&psc=1&refRID=GSPJYPBPA4CBH0402FV0
Hope this helps!
Thomas
that is a great effort ! loved reading it .
Great pieces of advice, especially the under estimate your pace. thank you