Training for my first 100-mile ultra: what changed after 30 marathons

My first 100-mile race was the Centurion South Downs Way 100 on 8–9 June 2024. I finished in 22:43:38, 126th overall, wearing bib 561; the result is on the official OpenTracking results page. Six months later I finished the Winter Downs 200 in 69:14:32.

By then I had run more than 30 marathons and several shorter ultras, including Madeira. None of that made 100 miles feel like a longer marathon. This page is about what changed in my preparation, drawn from what I said publicly at the time, mainly on the Running Tales podcast in October 2024. I am not a running coach, and this is not a plan to copy.

The biggest change: finally getting a coach

For about fifteen years I trained the way I wrote about after Barcelona in 2010: plenty of enthusiasm, little structure. On Running Tales I said I had only started working with a proper running coach about fourteen months before the interview, and that my main regret was waiting so many years to do it. In the written profile, I described the decision as having "transformed my running", even though we only ever worked together remotely.

The logic was the same as in business. I already relied on coaches and assistants at work; it made no sense to treat my running as the one area where I would work everything out alone. The longer story of that decision is in my adventures with hiring a running coach.

Strength work

The second change was adding strength training. For most of my marathon years I simply ran. In the interview I talked about starting regular strength sessions as part of the coached build. I will not put numbers on how much difference it made, because I did not measure it, but I would not prepare for another 100-miler without it.

Learning to walk properly

Most people picture ultrarunners running. On a hilly 100-mile course, a great deal of the time is spent walking, and walking well is a skill. I talked on the podcast about learning practical power-hiking and using poles in ultras. It is the least glamorous lesson and one of the most useful: if you cannot move efficiently uphill on foot, you burn energy you will need in the night.

Kit lessons, including one I would not repeat

I ran the 2024 South Downs Way 100 in road shoes. I mentioned it on the podcast as one of the things I had learned from rather than a recommendation. The South Downs Way is mostly chalk and grass trail; what works depends on conditions, your feet and the edition. Test your shoes on similar ground over long sessions before deciding.

What earlier ultras had already taught me

I also talked about mistakes on earlier long races, including Madeira. My original Madeira diary tells that story in full; the official record is a 115km finish at the Madeira Island Ultra Trail in April 2014 in 30:30:25. The broad lesson I carried forward was that long mountain and trail events punish poor pacing and poor fuelling far more than any marathon.

Why 100 miles is a different problem

On paper, 100 miles is about four marathons. In practice the differences are qualitative:

You run through a night. My SDW100 started at 06:00 on 8 June and the tracker recorded my finish in the early hours of 9 June.
You eat as a job. You need to keep fuelling for the best part of a day, not for three or four hours.
Checkpoints become decisions. Time spent at aid stations adds up across a whole day.
Walking is part of the race. See above.

The South Downs Way 100 race report walks through the public checkpoint times and what 22:43:38 does and does not tell you.

Then doubling it

When I recorded the Running Tales interview, I said I was aiming for a 200-mile race in December. That race was the Winter Downs 200, and the official result is now on record: 69:14:32, 18th overall, bib 167. The Winter Downs 200 feature covers the crew-supported logistics that a race of that length demands.

If you are planning your first 100

From my own experience only:

Get qualified coaching earlier than I did.
Add strength work, and build it in gradually.
Practise hiking hills, with poles if your race allows them.
Test shoes and fuel on long training days on similar terrain.
Read the organiser's current rules on kit, cut-offs and crew.

For the race-specific side of Centurion events, see my Centurion finisher's guide.

Questions readers ask

How long did your first 100-mile race take?

22:43:38 at the South Downs Way 100 on 8–9 June 2024, 126th overall, bib 561, per the official results page.

Did you use a coach for your first 100-miler?

Yes. I said on Running Tales in October 2024 that I had started with a running coach about fourteen months earlier and regretted not doing it years sooner.

Should I wear road shoes for the South Downs Way 100?

I did in 2024, but I would not recommend it as a rule. Test footwear on similar ground and conditions first.

Sources and notes

Podcast points are paraphrased from my own remarks; auto-captions were not quoted. I am not affiliated with Centurion Running.

Written in October 2026 from my own contemporaneous records.