However, Jones, who played a key role in Eliud Kipchoge’s sub two-hour marathon challenge in 2019, is keen to point out that the science in this area is “behind”.
“There isn’t as much hard evidence as there would be for shorter distances, which have been studied for a long time in quite some detail,” he adds.
That is a view shared by Dr Richard Burden, co-lead of female athlete health and performance at the UK Sports Institute, who feels a lot more information needs to be gathered before conclusions can be made.
“At the moment we are speculating … there are definitely some physiological adaptations that you see more in women than men that are favourable for ultra-type events. But those need to be better established and more studies would need to be done.”
Physiology, however, only gets you so far. The realities of ultra-endurance exercise – multi-day events, sleep deprivation, extreme terrain and conditions, to name but a few – mean the journey to the finish line is as much mental as it is physical.
And for Sophie Woods, this is where women have the edge.
“It’s not necessarily about being the fastest person at the start,” she says. “It is about preparation, it is about mental strength and being able to continue to persevere when things go wrong.”
During the New Zealand runner’s record-breaking run of the Via Alpina, she was forced to expect the unexpected – from disruption caused by wildfires that made her route longer and more dangerous to swarms of horseflies.
“I was so tired and there were so many of them and I wanted to have a complete meltdown and just cry, but I couldn’t because if I stopped moving, they started biting me,” she says.
“I think women are really good at adapting and continuing and just knowing that once we start something, you’ve just got to keep moving until you get to the finish.”
That view is echoed by Yngvild Kaspersen, who last month became the first woman to win the prestigious Ultra-Trail Mont Blanc CCC race in the Alps twice. She credits her victory to the “mental game” she puts herself through in training.
The Norwegian, who balances life as a professional runner with her job as a GP, also believes female ultra-runners are so strong because camaraderie in the community is unrivalled.
“We’re competitors but we’re also motivating each other, inspiring each other, pushing each other to do better in the races,” she says. “If you see the podiums for the women this year [at UTMB], how close we are and how we’re running together out there – that’s very special and I’m very proud to be a part of that community and that group of women.”
So can we explain why women might be more resilient?
Sports dietitian Renee McGregor, who specialises in athlete nutrition and hormonal health, believes the answer comes from the female body itself.
“The moment women step into puberty, we are dealing with a fluctuating hormonal system,” she says. “We never ever give ourselves credit for that, it’s just an accepted part of being female. But actually, it is an endurance in itself and I think that’s probably where a big part of our resilience comes from.”
McGregor, an ultra-runner herself, points to research that suggests female runners display more disciplined and even pacing strategies than men in distance races, maximising on what she terms the female “brain bank”.
“I don’t think women go into these races without a lot of thought and contingency planning,” McGregor adds.
“For example, if you’ve been through a pregnancy and you’ve dealt with nausea, if you’ve had a baby and dealt with the lack of sleep or if you’ve gone through fertility treatment, you have to go through so much discomfort, but you know you can get through it. And I think it’s that knowledge of ‘I can get through this, I can find a solution’.”