It seems as if Martin Mack’s ultramarathon days may be over.

Though he completed the 42.2-kilometre final segment from Oued el Jdaid to Koura Dial Zaid in 6 hours, 32 minutes and 30 seconds—and moved up 69 places to 699th among the 1,240 runners who survived the first four stages to start Friday’s final leg—it was a difficult day, Mack wrote in what he called “my last desert email ever.”

“After my poor performance on the (previous) 92-kilometre stage, I was looking for some redemption,” he wrote.

On the final day of his fifth Marathon des Sables, Mack wrote that it took 20 minutes to put on his socks and shoes, due to the tape protecting the blisters on his feet that developed over the first 208 kilometres of the six-day endurance test over the Moroccan Sahara Desert.

Mack’s plan was to walk the first part of Friday’s stage, but that lasted only five minutes. “It didn’t feel good to walk, so I tried to run, and it felt better to run.

“I popped on the music and said I’ve had enough and need to be done with this last 42 kilometres—and I popped a lot of pain meds.”

The terrain was mostly rocky and flat, with only a few small sand dunes that forced Mack to walk. After the day’s fourth checkpoint, with 8.5 kilometres to go, he wrote that it was time to pull out the M&Ms his daughters had sent overseas with him and “hit the run hard.”

 “I ran well,” he wrote, “all the way to the finish.”

Mack ended the race fourth among Canadians, 22 of whom began the ordeal Sunday, 20 of whom answered the call to start the final stage Friday. He completed the 250-kilometre course in 50 hours, 4 minutes, 27 seconds.

The race was won by defending champion Rachid el Morabity of Morocco, who finished the race in 20 hours, 21 minutes, 39 seconds; claiming his third title, this time by 13 minutes, 14 seconds over countryman Abdelkader el Mouaziz.