All eyes on the CCC: How Juliette Denny is preparing for her first 100km Alpine race

Meet Juliette Denny, an ultrarunner and SportsShoes.com ambassador who recently completed the grueling 42 km Mont Blanc Marathon, using it as a strategic launchpad into her debut 100km challenge: the CCC later this summer.

The recent Alpine race, with steep ascents and dramatic scenery, offered her a fierce testing ground just months before she takes on the full circuit of the Mont Blanc massif as part of the UTMB Trail running race series.

Juliette’s journey into endurance sport began not on trails, but on the football pitch. She played competitively from a young age, even captaining an all‑girls team that won their league five years running.

However, after tragically losing a close friend in 2017, she sought solace and purpose in running, turning to the South Downs Way 100‑mile challenge to channel grief into action. That emotional milestone launched a deep love for ultra distances: multi‑day desert races, Patagonia treks, and an Ironman in Barcelona soon followed.

Beyond her athletic feats, Juliette is fiercely committed to making the outdoors more inclusive. As an active member of Black Trail Runners, she champions representation and access, especially for women and young people from diverse backgrounds.

Her advocacy and achievements saw her used as the cover star of Women’s Running magazine in April 2023, a powerful visual testament to her impact in shifting who we see on trails and in finish-line photos.

Now, standing on the threshold of her first ultra 100 km at the CCC (Courmayeur/Champex/Chamonix), Juliette will head to Chamonix armed with mountains of experience – and introspection. From her Mont Blanc Marathon insights to fine-tuning descents, nutrition and mental grit, she’s ready to take on the challenge of a lifetime.

You live on the south coast of England – how do you prepare for mountain races?

“It's something that's really difficult for me. Being based in Brighton, I'm at sea level. Training at altitude is expensive, whether it's through an altitude centre or a tent. All those things are difficult to access. So I haven’t really been preparing for altitude because it’s not something that’s accessible to me at the moment.

“I think that’s probably similar for a lot of people training for these events. What I can do is train for the elevation itself and try to make sure my base level of fitness is strong.

“I’ve been working to get my heart rate as low as possible, so that when I’m out on the trails and my heart rate inevitably rises, I’m not pushing into the really high zones because I'm already used to working efficiently at a lower effort.

“So my training isn’t specifically focused on altitude. It’s more that Alpine events force me to train at a slower, steadier level instead of always pushing to my limit. With the number of hours I’ll be out there, I can’t be going 100% all the time.”

So it must be equally hard to prep for big ascents and descents?

“I actually think it’s easier to train for the climbs than for the descents. They’re both really hard, but physically it’s easier to access ways to train for climbing. Even if you’re not in mountainous areas, you can head to the gym, get on a treadmill at a high incline, or use a step machine to at least replicate that effort.

“I’m lucky that I have the South Downs near me. While they’re not mountains, they’re still hills. I’ve hit some good inclines and included as much elevation as possible in all my long runs.

“The biggest challenge has been finding elevation at the steep percentages we’ll face. It’s hard to find steep trails that last long enough around here. I’ve been driving out to places like Pen y Fan, which is the closest proper mountain to me.”

And what about the heat? Alpine summers can be challenging!

“Thankfully, it’s been hot in the UK lately, which has been helpful. I made sure to get out during the hottest part of the day in the recent heatwaves to train.

“The main thing I’ve done is prep my fueling and hydration. I want to make sure I’m getting electrolytes and carbs in regularly so I can cope with the temperatures. Kit-wise, I’m using really lightweight gear that’s breathable but still protective for the mountains. Just being sensible with my clothing and hydration has been key.”

What’s your approach to fuelling and hydration for long races like this?

“I’m not a nutritionist or coach, but I’ve found that liquid carbs work best for me. Better than gels or solid foods, especially when it’s hot. I often don’t feel like eating much, so sipping on carbs works better.

“My baseline is 60g of carbs per hour, but I usually aim for more. I use carb drinks that give me 90g of carbs every 90 minutes, then top that up at aid stations with things like salted potatoes and watermelon. If I’ve fallen behind on my fueling, I’ll have a gel to catch up.

“Something I’ve learned the hard way is that I can’t rely on gels alone – my stomach can’t handle it. The intensity of carbs in them just doesn’t work for me. So sipping slowly on liquid carbs is what works best.”

Let’s talk about kit. What are the essentials you rely on when racing?

“My Salomon pack is essential – it has to carry all my mandatory kit, water, and fuel. I tested a few and borrowed some from friends before settling on one that worked.

“Poles are also absolutely essential for me. I use the Leki Ultratrail FX.One and I wouldn’t do a race like this without them. They’re helpful not only going up but also coming down, supporting posture and saving your legs.

“I’ve been trying to incorporate poles more into my training though. The biggest thing is getting into a rhythm – watching others at events has helped me learn. Going uphill, I focus on posture and rhythm. Going downhill, lots of little steps, and using the poles for balance and support really helps.”

Any bits of gear you couldn’t go without?

“Definitely my shoes. I’ve been using the New Balance Fresh Foam X Hierro v9, and I’ve been using their previous models for years. They’re comfortable and work well on varied terrain.

"Sunglasses are also essential. Even with a hat, the brightness in the mountains can be intense and give me headaches, especially looking down at reflective trails. So sunglasses are a must.”

What about mental prep? Do you have strategies for getting through low moments?

“This is a really interesting one. I think I could be better at mental prep, but this time I’ve focused more on acknowledging that it’s going to be hard. I’ve tried to plan what I’ll say to myself in those low moments – reminding myself that I’ve done hard things before and I can get through this too.

“Knowing that people are supporting me and are proud of me helps a lot. Visualising seeing them at the next aid station is a motivator. Also, reminding myself that I chose to be here, and that it’s a privilege to be exhausted by something I chose to do. That mindset really helps.”

Do you go into races with a specific time goal, or just for the experience?

“It’s a personal challenge for me. I want to enjoy parts of it, have good memories, and take in where I am. I want to finish knowing I’ve nailed my nutrition and kept going even when I was tired or hot. It’s going to be hard – that’s the point – but it’ll also be really rewarding.”

And finally… what emotions do you get from racing in the mountains?

**“**The steepness of the trails makes me nervous, both going up and coming down. Sometimes it feels like walking up a wall. But what excites me is getting to the top and looking around at 360 degrees of stunning mountains. That’s always so special.

“I love the simplicity of mountain running. You’re just putting one foot in front of the other. It might be the hardest thing you’ve ever done, but also the most rewarding.”

Kit yourself out like Juliette