How to train for your first 100 mile ultra
The 100 mile ultra distance seems to be the topic on so many of my athletes' lips right now. For many it can seem like the natural progression if you’ve already completed some of the shorter ultra marathon distances like 50 miles or 100k. But make no mistake, 100 miles isn’t for everyone.
I don’t know who needs to hear this right now but you do not need to sign up for a 100 mile race if you are an ultrarunner.
And just because you haven’t finished a 100 mile race before does not make you any less of an ultrarunner. There are so many other types of ultramarathon distances out there that are underrated and take up way less of your time.
I wanted to chat with one of my long standing athletes, Sarah who’s recently completed her first 100 mile ultra marathon, The Thames Path 100 by Centurion Running to get some 100 mile ultra tips from someone who's been there.
Why 100 miles and which event did you sign up for?
It seemed like a natural progression as I'd already done 50k, 50M, 100k, 250k multi stage... Plus I had previously enjoyed the longer distances (such as the long stage at the MDS) and wanted to see if that continued at even longer ones. I feel like I'm still "finding my feet" with all the different types of ultras out there (trail, road, mountain, flat, single stage, multi stage, various distances) and this was a distance I had yet to try but had an inkling I would enjoy.
I signed up for the Thames Path 100 organised by Centurion Running. It's a point to point race that starts in Richmond in South West London to the centre of Oxford, following the route of the River Thames. It's renowned for being flat and fast because most of the course is on groomed trails and paved paths. I'd previously lived in Richmond and spent my University days in Oxford so both places held some meaning.
How did you know you were ready a 100 mile ultra?
When they handed me my buckle! Ha, half joking. As I mentioned above, it seemed like a natural progression. I spoke to other ultra runners who had done the distance who didn't seem all that different to me. Even so, I had a bit of a panic 6 weeks or so before and needed to do a bit of mindset work (with Dawn Blackwell) to reassure me that I had what it took.
My physical training was going well and I couldn't have done more in that respect (Hannah's programming was spot on and flexible around family holidays/school terms etc.). I also calmed down a lot once the kit and planning spreadsheets were completed (again, Hannah's help with this was invaluable) so I felt more in control.
What percentage of the race would you say you ran versus walked?
I ran pretty much all of the first 120k and due to muddy conditions walked much of the last 45k! I wish conditions had been better so I could have run a bit more.
How did your nutrition in the first 50 miles differ to the final 50 miles?
I was able to eat more real food in the first 50M. Towards the end my reliance on easier to eat foods such as gels, sweets, and Tailwind increased. I have discovered I can pretty much always stomach jaffa cakes, white chocolate and marmite sandwiches!
One food that got you through 100-miles?
Jaffa cakes.
What was your longest training run/weekend?
I signed up for the Chester Ultra 50 two months before Thames Path. I had planned on using the Goodwood marathon three weeks before my 50 mile race as a long train run, I remember looking at my watch and realising I was well ahead of schedule. I felt so strong and natural at this quicker pace, I decided to carry on as I wanted to bank my good age qualifying times for London and maybe Boston.
Six months before Thames Path, I also had The Druid’s Challenge by Extreme Energy. I covered just short of 100 miles (85 miles) across 3-days. But my longest run in training that wasn’t one of the above races was only 35 km/ 22 miles.
How do long runs differ from prep for 100km or a 50-miler?
Chester Ultra 50 was my first standalone 50-mile race but I'd worked with my coach Hannah to schedule this as a long training run two months before my 100 mile race so I was always training with the bigger goal of 100-miles in mind.
The Serpent Trail 100km was my first 100km in July 2022. I used a local 50km race as my long training run in the build up to this but my longest run in training that wasn’t an organised race was a half marathon distance.
In the training blocks building towards my 100km, I was taking two sometimes three rest days a week but when I moved up to the 100 mile distance this was more like one rest day a week and occasionally two but I was really focused my making sure I was taking my rest days seriously and my easy run or recovery days were truly easy.
What kind of lead time training block from a decent base is required to feel ready for 100 miles?
I don’t think you ever feel truly ready. As I half joked above, I only knew I was ready for the distance when they handed me my buckle at the finish line!
I’ve been working with Hannah for 2.5 years now and back then was really into CrossFit training 5-6 times a week. I used to love the 10 mile or half marathon distance but I was only running a couple of times a week and it felt a bit directionless.
In the 6-months before my first 100 mile race, I was running on average seven hours a week and strength training 2-3 times a week. In my peak volume weeks, my running moved up to 11 hours a week but this only happened on three occasions.
What surprised you the most about the 100-mile distance?
In my mind 100M was set apart somehow - there was a huge mental jump from 100k. In reality this wasn't the case. Apart from going through the night it really wasn't much different to 50M or 100k. You might just have more lows to rebound from. I worked with my mindset coach on the rebuild process. In all though, it's just one foot in front of the other for longer!
Your biggest learning coming out of the race?
You are stronger than you think you are. You can do hard things. I felt elated and rode the high of this achievement for a good couple of weeks after and even now it has given me an inner confidence.
Fun bonus fact - women are very underrepresented at the longer distances (something SheRACES and people like Hannah are working to address) so you might feel a little outnumbered at the start line but consistently women's DNF rates are lower than men's. You can do this!
Ultramarathon Coaching
Hi, I’m Hannah. I’m obsessed with getting more women onto ultramarathon start lines by giving you the skills and confidence so you can finally realise what you’re truly capable of and more!
I support you with everything you need to show up to the start line of your event leaving no stone unturned, whether it’s your first 50K or 100 mile ultra.
Maybe you’ve had a recent DNF (Did Not Finish) at a 100 mile race or want to tackle the distance in the future?