Explainer | What is an ultramarathon, how far and on what terrain?

Ultra running is exploding in popularity around the world, but what actually constitutes ‘ultra’ in an ultramarathon?
The term covers a broad range of races, from mountains to road

Extreme fitness

Mark Agnew

Published: 12:00pm, 25 Jun 2022

Why you can trust SCMP

Ultra running is fast becoming a mainstream sport. Once, it was the realm of a few crazy runners, and not the pastime of everyone from your boss to your neighbour. But what actually is an ultramarathon?

How long is an ultramarathon?

An ultramarathon is anything longer than a marathon, which is 26.2 miles (42.195km). So, you could complete a marathon and run back to your car and you’ve technically run an ultra distance.

Typically, ultramarathons start at 50km and go up from there. Standard distances are 50km, 100km and 161km (100 miles), the latter often being referred to as a “miler”.

A stage race over a few days is a popular ultra format. Photo: Agence France-Presse

While a marathon is never longer than 26.2 miles, ultras tend to vary a bit. For example, the Hong Kong 100 is in fact 103km. And the Ultra Marathon du Mont Blanc, a miler, is in fact 171km. Others are a bit shorter than advertised, too.

What to do if you keep retwisting your ankle when running

Aside from the above three types, there are ultra races of all sorts of distances and formats. As long as it’s more than a marathon, the distances and formats can be limitless.

An increasingly popular format is 250km split over stages, such as the Marathon Des Sables. Runners complete different distances each day, some less than an ultra, and sleep at night.

As the sport continues to grow, others try to push the boundaries – such as the 298km Hong Kong Four Trails Ultra Challenge, which is non-stop and has no support on the trails. Runners finish the distance in between around 48 and 70 hours.

Kilian Jornet is considered one of the best ultra mountain runners. Photo: Sergi Colomé

The formats are becoming increasingly imaginative. A backyard ultra, for example, is around a 6.7km loop. The runners start on the hour every hour until there is just one runner left, so the distance is not set. It keeps going and going. Runners have gone on for more than 80 hours.

Outside organised events, runners often complete ultramarathons just for fun, to set a personal best or a Fastest Known Time (FKT), which is ultra terminology for a specific course record. This can be anything from the 44km Hong Kong Trail, which takes a few hours, to the 4,172km Pacific Crest Trail, which has an FKT of almost two months.

What terrain is an ultramarathon on?

With an infinite range of distances come infinite terrains. An ultramarathon can be road, flat, track, pavement, mountain, trail, snow and more. As long as you can run on it, you can run an ultramarathon on it.

A famous road ultramarathon is the 246km Spartathlon. It follows the legendary route run by Pheidippides, who ran from Athens to Sparta before the Battle of Marathon in Ancient Greece, thus inventing the marathon.

The most high-profile mountain ultra is the Ultra Marathon du Mont Blanc, which has a total of 10,040 metres accumulative elevation gain in the Alps.

Yiannis Kouros is one of the best ultra road runners of all time. The disciplines between different terrains are impossible to compare. Photo: Facebook

Track ultras often take the format of a set time rather than distance. For example, how far you can travel in 24 hours, round and round the same athletics track.

When Zach Bitter set the 100-mile world record, which has since been broken again, he ran it around a 443m track by doing 363 laps.

The distances and terrains are so varied race to race they are essentially different sports. Kilian Jornet is considered one of the best ultra-mountain runners ever, but comparing him with Yiannis Kouros, considered one of the best ultra road runners ever, is like asking who is better at football: Tom Brady or Lionel Messi.

Is an ultra harder than a marathon?

The word ultra refers to the distance, not difficulty. An ultramarathon is inherently hard, but not inherently harder than a marathon or any other distance for that matter.

If you have a specific and demanding finishing time in mind for your marathon, you will have to stick to a specific split, keep your legs spinning and spinning, all the time concentrating on your pace and pushing your body.

Is that easier or harder than a 24-hour 100km over mountains, with variation in terrain and elevation, when you walk some parts and rest at check points?

Ruth Croft running in the Golden Trail Series. Photo: Golden Trail Series

What about a 5km? If you want to run a fast 5km, you will be at your absolute limit for the entire time and collapse over the finish line.

Non-runners often think an ultramarathon is the “next step” for runners looking for a new challenge. Searching for a faster time is just as challenging as searching for a longer distance.

Either can be harder than the other – it’s down to the runner.

The same is true within ultra running. Ruth Croft, one of the best runners, dominates races around 50km. She was repeatedly asked when she would do a 100 miler once she had “completed” a 50km. Croft resisted the urge to cave to the pressure to run further until she was ready, understanding that fast and far are two often incomparable metrics.

When you consider all of the above, the simple definition of “longer than a marathon” does not quite do justice to the massive range of events encapsulated by the term ultramarathon.