This event is scheduled to go ahead, with some differences. Read our Covid-19 policy
This event is scheduled to go ahead, with some differences. Read our Covid-19 policy
No. of days 1 day
Distance 31 mi
Ascent gain 979 m
Accom. no
Food no
A 50km, one-day ultra marathon in the picture-perfect Chilterns in aid of funding life-changing operations for children in developing countries.
The ideal 50km introduction to ultra marathon running. Escape to the Chilterns, an area of outstanding natural beauty. What's more, it's FREE to run, if you commit to raising funds for Humanity Direct.
The winners, runners up and age group winners will receive fantastic prizes or vouchers from our sponsors.
The well-marked circular route will start and finish at Princes Risborough School. Using National Trails and Footpaths, there are clear signposts and post discs, as well as our signs and confidence tape.
We'll also give you a handy map, designed to help on any tricky sections. We recommend familiarising yourself with the route before the start of the race.
07:00
Minibus pick up starts from Princes Risborough Station
07:00
Registration opens.
07:30
Walkers briefing.
08:00
Walkers start.
08:30
Runners briefing.
09:00
Runners start.
09:30
Elite runners briefing (target time below 6 hours)
10:00
Elite runners start.
14:00
Refreshments available.
14:00
Minibus to the station running all afternoon
16:00
Prize giving or when enough runners have finished.
£58
FREE
The £58 entry fee will be donated to fund a vital operation, or alternatively enter for FREE, if you commit to raise funds for Humanity Direct.
If you're fundraising book now through our system, then visit Humanity Direct's website to register yourself.
Please note: a 2.5% service charge, levied by the registration software, will be added to your total. We are using a new entry system that takes payment through the secure system Stripe. No payment information is retained by Extreme Energy, or our entry system tool.
Email us on info@xnrg.co.uk if you have any questions about your options.
No refunds or deferrals will be made within one month of the event start.
The only compulsory kit is a fully charged mobile phone and a minimum 500ml of water, but it's worth taking a look at our recommended kit list.
Other equipment may be made compulsory by the race director depending on the weather.
The event is supported by a Course Manager and a fully qualified medical crew will be in attendance. We strongly recommend taking a moment to read our medical page before booking.
We've answered a range of common questions in our FAQ. For other questions, say hello on info@xnrg.co.uk.
This popular race is especially good for those looking for a supportive event for their first ultra within easy reach of London.
As with all of our events, everything is taken care of at the Chiltern Challenge so you can focus on the experience! We’ll provide transfers from the station, free parking, free photos, changing facilities and heaps of tea and cake.
The XNRG Chiltern Challenge is a unique chance to get a place on an amazing one day ultra for FREE if you fundraise for a Humanity Direct patient, or donate £58.
In 2019 Humanity Direct raised £24,000 through the three Humanity Direct Ultras, which helped fund life saving and life changing operations for 35 children and we are hoping to raise even more in 2021.
It's simple. The entry fee for the one-day ultra-marathon is donated to fund a vital operation or, if you prefer, you can enter for free and start a fundraising page instead and raise as much as you can, with a minimum of £58.
Entries will close one week before the event (or when full). A waitlist option will be available if the event becomes fully booked.
Stretching from the River Thames in Oxfordshire to Hitchin in Hertfordshire, the Chiltern Hills are a spectacular Area of Natural Beauty boasting some of the finest protected countryside in the UK.
The well-marked circular route will start and finish at Princes Risborough School (HP27 0DR), incorporating four checkpoints, approximately 10km apart.
Using National Trails and Footpaths, there are clear signposts and post discs, as well as our signs and confidence tape. We'll also give you a handy map, designed to help on any tricky sections. We recommend familiarising yourself with the route before the start of the race.
There will be four checkpoints at regular intervals with water and food - please bring your own cups.
Due to the risk of cross contamination, we cannot provide checkpoint food to suit all dietary requirements. If you require special food or snacks to suit any allergies or vegetarian/vegan diets, can you please bring your own. Put them in containers, marked with your name and checkpoint number and give them to the checkpoint teams at the start of the race.
A stone's throw from London, there are a few options for reaching the race.
Trains with Chiltern Railways run from London Marylebone every half an hour, taking between 30 and 58 minutes to reach Princes Risborough. Trains from Birmingham leave approximately every 30 minutes and take around 1hr30. We'll be running a minibus shuttle to and from the station in line with registration and finish times.
Princes Risborough is about a 20 minute drive on the A4010 from Junction 4 of the M40 (High Wycombe) or 20 minutes on the B4009 from Junction 6 of the M40. There will be free parking all day at the school.
Hi, I don't usually respond to organisers after an event. I just wanted to say thanks for organising such an amazing first ultra. The race was superbly organised , well planned , Marshall ands food stops were excellent. I can assure you I will be running in your events again and recommend them to others. Thank you and your team for making the chilterns ultra such a great run.
Hi everybody I would like to congratulate XNRG on a superbly well run event in the Chilterns. It was a fabulous day out in stunning countryside. Everything went like clockwork, registration, briefing and the course was marked perfectly with tape, signs and sometimes quite elaborate pictograms sprayed on the ground making the maps supplied only necessary as an overview of the route. I find it quite mind boggling that you can plot and mark such a varied and interesting course in 31 miles of countryside, check it and then clear up afterwards. It made the entry fee worth it alone.
Just wanted to say thank you to everyone who helped with this event yesterday. It was my first ultra and I absolutely loved it! The fantastic organisation meant all I had to do was concentrate on getting myself round the distance! The malt loaf and coke at the checkpoints were a much needed treat! Thanks again.
We can't wait to see you there! Questions? Say hello on info@xnrg.co.uk