GoKawiilHowever, 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."
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