As part of his training, South African Jethro de Decker has been running and walking for over a month with his trusty companion Denzil.
But Denzil is no ordinary training partner or coach - it is, in fact, a 10kg tyre that the 1.72m de Decker straps to his body and drags around in preparation for a quest he hopes to complete at the end of next year: an unassisted solo trek across Antarctica to the South Pole.
Ask the 33-year-old why, and one word is peppered throughout his answers - challenge.
Explaining how the challenge is both physical and mental, he said: "The most difficult part is not walking in the cold; it's starting out and deciding to do it, and taking that first step.
"Once you start the process it's actually a whole adventure and it's exciting from day one; it's been exciting for the last few months and it's going to be exciting till I finish it."
De Decker, who weighs 66kg, made the decision to trek to the South Pole at the end of last year.
WEIGHT OF EXPECTATIONS
Once you start the process it's actually a whole adventure and it's exciting from day one; it's been exciting for the last few months and it's going to be exciting till I finish it.
JETHRO DE DECKER, on preparing to trek solo from Antarctica to the South Pole.
To prepare for it, he ran 170km at the Grand Raid Reunion (a mountain ultramarathon on Reunion Island) last year, participated in the Baikal Ice Marathon in Siberia in March to experience extremely cold temperatures, and will be dragging Denzil behind him when he enters next month's Standard Chartered Marathon Singapore.
"So far the longest I've walked with the tyre is 30km," said de Decker, an actuary at Citibank.
"The Standard Chartered Marathon will be the longest that I would have run or walked with the tyre (42.195km), which I'll aim to do in seven hours, or however long it takes."
Through taking on the challenge of the estimated 650km journey from Antarctica to the South Pole, he will also be raising funds for Conservacion Patagonica, an organisation that works to create national parks in Patagonia that save and restore wildlands and wildlife.
But there are times when he does not enjoy the process.
"When you're eight or nine hours into dragging a tyre for two nights in a row, walking around the stadium and the lights are off because everyone's sleeping, and you're hungry and wondering why you're dragging your tyre around… it's not the most pleasant thing," he said.
"But then I imagine what it's going to be like to cross the finish line and it inspires me to keep going."
To add more realism to his training, he sometimes adds a second 10kg tyre, named Hugh, to simulate the effort of dragging his own supplies to the South Pole.
He listed three targets in order of descending priority - to come home alive with all his fingers and toes intact, to reach the South Pole, and to do complete his journey as fast as possible.
Apart from battling the cold and the weight of his supplies (food, tent, warm clothing), he has another enemy to overcome - sleep deprivation.
Although it will be an obstacle on the journey to the South Pole, he believes that experiencing sleep deprivation while training is a sign that he is on the right track.
"I've only done five hours at a time with the tyre, but I think when it starts getting longer and I start getting some proper sleep deprivation, I might start talking to Denzil," he said.
De Decker, asked what he thinks Denzil would say in response, laughed before answering: "I think Denzil would say I need to pick up the pace a bit."