Ultramarathon runner Ariel Rosenfeld is never one to avoid a challenge.
He has already completed the legendary Spartathon, a six-section race run without breaks across Greece, creating a 246 km (153 mile) course.
Roughly the equivalent of six marathons end to end, the Spartathlon runs from Athens to Ancient Sparta and is inspired by the historical account of Pheidippides and the Battle of Marathon.
Runners climb 1200 metres (3900 feet) up Mount Parthenion and have to contend with the heat of the Greek sun and the cold night. It’s not a race for anyone except the elite.
Rosenfeld was one of the 391 who started the race.
"My philosophy is that I don't run 'against' other runners" he says.
"The challenge is very individual and during the race I'm trying to see if I can help other runners as well. In the Spartathlon I have the privilege to run with the best runners in the world, both physically and mentally."
This meant he wasn’t aiming to beat anyone; it was more a case of beating the course.
"In such long ultra marathons, I always prefer to stick to my plan, balancing heart rate, pace and feeling," he says.
"The goal for me in the Sparatathlon is to finish.”
However, as we would expect with such an experienced and accomplished runner, Rosenfeld's standards were high.
He had completed the Spartathlon one before, and this gave him something to compare this experience with.
“The race was way better than my expectations. It was very tough of course, but I had much better sense of what I'm doing and why," he says.
"This has a lot to do with the fact that it was my second time in the Spartathlon race and I knew what to expect.
"The main difference from 2015 race was that this time I could run the long downhills after the 200km mark. In 2015 I could just walk them very slowly.”
Of the 391 runners taking part, 265 finished.
Races of this grade always claim their victims, whether through injury, heat, or sheer pain and exhaustion, although the Spartathlon also has strict cut-offs at six points, and runners who have not made the check points by the given time are eliminated.
Rosenfeld finished in 47th place, with a time of 30 hours 11 minutes and 47 seconds. This placed him in the top 18 percent of finishers and top 12 percent including those who didn’t finish.
"I finished six hours faster than the cut off and improved my time by 35 minutes from 2015," said Rosenfeld.
The athlete turned vegan in 2012, after a year of vegetarianism. "I saw a Gary Yourofsky movie,” he told us, "and that put a mirror in front of me."