Joseph Grosvenor an ultra runner to watch

Last updated: 05-Nov-18

By Kerry Sutton

100 miles in 20hrs and 57mins is not an extraordinary time in itself, until you find out the runner is only 16 years old…

I interviewed Joseph a couple of years ago after his first foray into ultra running and was fascinated to hear about his motivation, training and what he experienced during the race itself. There is no doubt he is an extraordinary teenager, not only is he achieving impressive results in the world of running: but he has just won a sixth form scholarship to Eton from a local state school.

I couldn’t wait to talk to him again and find out how his attempt at breaking 24 hours for a 100 miler had gone.

Q. Firstly, congratulations on your 100 mile run which you completed in a record 20hrs and 57mins (this is an unconfirmed record but after much searching we cannot find anyone who has done it faster). It’s an extremely impressive time. Congratulations as well on your scholarship to Eton, is there anything you can’t do!  Let’s start with a quick recap on how you got into running and running long in particular.

A. I have always played an array of sports and enjoy running at my local athletics club. It soon became apparent that I was having more success over longer distances and so I was intrigued as to how far I could go. As a result, a couple of years ago I completed my first ultra. It was a 100 miler, in 48 hours, which allowed for a small amount of sleep and enabled me to walk large stretches.

After that, I was ardent to go faster and 24 hours seemed like the logical next goal, so when I managed that this summer doing it in 20hrs 57mins, I was ecstatic.

Q. Can you describe what is it that you love about ultra running?

A. When playing team-sports, I often suffer from nerves due to the many factors influencing the result, many of which are out of my control. However, ultra running is far more simplistic and I enjoy the feeling of being in control, whilst still being pushed to my physical and mental limit.

Q. I think many ultra runners would agree with you and also love of the simplicity of running. Completing a race of this length takes careful management of your nutrition, pacing and mental strength. What was the most challenging part of the ultra for you?

A. The first 30 miles were difficult because my partner, Elliot, and I, went off very fast, completing the first marathon in 3hrs 15mins, and as a result we were really struggling (we had planned to go off fast to reduce the pressure of the time restriction that we had put on ourselves).

Between mile 30 and mile 70, however, we were able to maintain a steady pace, relatively comfortably, and I felt a little dazed during this period. But, without a doubt, the last 30 miles were the hardest, as it was around 4am and I was being violently sick and having to claw my way to the finish.

Q. Wow that’s quite a risky race strategy and sounds pretty horrendous. So mental strength was ultimately what got you through? Did you draw on any mantras or thoughts that helped you keep going when it was tough?

A. I listen to the song “Carry On” by Fun before any big exam or sporting fixture to help focus and relax. I also remember the words of my coach before I ran my first cross-country race; he told me to “put one foot in front of the other and just run”.

Q. Can you describe the course, who organises the event and what support is provided.

A. The event is called The Centurion Challenge and is run by my (now former) school, Beechen Cliff, as a 48-hour ultra-walking event. When I was 13 I was one of the select few that opted to run the event finishing in around 42 hours. This year, however, I took part in the event but independent of the school event (although I made my attempt along the same route at the same weekend).

I ran from Bath to Hungerford…and back. The course was legitimised by teachers who cycled the route with GPS trackers on their bikes to confirm that the route is, in fact, 100 miles. Between Elliot and I, we carried very little and my parents leapfrogged our progress in the car so we could top up on food.

Q. You have done a couple of 100 milers now and run countless other races of varying length. What do you think you have learnt from competing in these races and putting yourself in challenging situations when your body is screaming at you to stop!?

A. I heard a story about a marine that was told to do as many pull-ups as he could; when he had completed 20, and felt he couldn’t do anymore, he was made to do another 100 to prove that physical capabilities are limited by mental strength and that people are capable of more than they think.

Doing ultras has taught me this lesson first-hand, albeit rather painfully. It has also given me self-confidence knowing that I can set big goals and achieve them

Q. What does your training for an event of this magnitude look like and how do you fit it in with school work, etc.

A. I started training in October to complete the ultra in July. For those 10 months it was my main sporting focus and I had to sacrifice involvement in rugby and football to allow for the miles that I was running per week. I also had my GCSE’s and Eton and Harrow entrance exams to contend with in the months prior to July. As a result, I often ended up running before school, at 4 or 5am to make time for revision, school and exams.

My training also wasn’t helped by a puncture wound I suffered to my leg in April whilst doing high jump, which took three weeks to recover from. Overall, the training itself wasn’t too bad because I enjoy running but often making time for it was difficult.

Q. That shows your commitment and sheer determination to achieve great things. Most other children your age would have given up with half of the pressure you had. In the knowledge that you are stressing your body in an extreme way, what measures do you put in place to protect yourself from long term damage?

A. I stretch regularly, use a foam roller and do an intense strength and conditioning programme. The only other measure I take is to make sure that I do not overtrain. Spending large amounts of time in the gym and on the foam roller helps reduce the probability of long term damage, however overtraining can easily undo this.

I also spent two years training specifically for my 24-hour attempt which I feel helped protect my body. It meant my training was tailored in such a way that I peaked at the time of the event, thus helping to reduce the toll on my body.

I also think that an element of common sense is required. I was going to make my attempt a year earlier than I did,  but I was still nursing a very minor niggling knee injury and so, although it had not proven to be a problem in training, I opted to let it recover fully and had to make the difficult decision to put my initial attempt off. The importance of being sensible as a young ultra runner cannot, in my opinion, be overemphasised.

Q. So let’s finish with looking ahead. What have you got planned and what do you hope to achieve in the future?

A. I’m not too sure at the moment. I love skiing, climbing and trail running in the mountains, so I would love to do an ultra ski-mountaineering event one day. I also hope to take part in the Salomon Running Academy next year around April and May.

I would like to shift my focus towards more technical trails and incorporate more hills, because all the ultras I have done so far have been along canal paths and through fields, and I would just like to mix it up a little.


Thank you for your time, Joseph, and good luck with all you put your mind to in the future!

Kerry Sutton – is a running coach focused on harnessing the power of the mental and the physical self. 

"The importance of being sensible as a young ultra runner cannot, in my opinion, be overemphasised"

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Global - Virtual


A virtual race which can be run at any time shown on the dates shown, on any type of terrain in any country.

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For runners from beginners to experienced as you choose your own course and challenge based on the guidelines and options set by the virtual race organiser.

Endurance - Multi-activity


An ultra distance race including at least two of the following activities such as running, swimming, cycling, kayaking, skiing and climbing. It may also include different climatic conditions (eg ice, snow, humidity, cold water, mud or heat).

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Experienced multi-skilled athletes who have trained for the different activities included in this event. Admission to these races may be subject to receipt of a recent medical examination certificate. Check with the race organiser regarding entry requirements and any specialist equipment required such as a wetsuit, skis or a mountain bike.



Increase of up to 2000 metres with very challenging climatic conditions (e.g. ice, snow, humidity, heat or at high altitude)

Suitable for

Very experienced long distance ultra runners (min 3 years’ experience) or are doing regular long distance running (>50 miles) with elevation and conditions shown (where possible). Admission to these races is often subject to receipt of a recent medical examination certificate. Purchase of specialist kit is often recommended for these races.



Increase of up to 2000 metres with some challenging climatic conditions (e.g. ice, snow, humidity or heat)

Suitable for

Experienced runners who have completed at least 4 ultras in last 12 months, or are doing regular long distance running (>50 miles) with elevation and conditions shown (where possible). Admission to these races may be subject to receipt of a recent medical examination certificate. Check with the race organiser regarding entry requirements.



Increase of up to 1500 metres

Suitable for

Runners who have completed several ultra distances or similar events, or are doing long distance running regularly, with elevation shown.



Increase of up to 1000 metres

Suitable for

Runners who have completed at least one ultra in last 6 months or are doing long distance running (>26 miles) regularly, with elevation shown.



Very little change < 500 metres

Suitable for

First ultra event. Runners completing a marathon or doing regular long distance running (>26 miles) in the last 6 months.