VIDEO: Antarctic marathoners survive big chill

A thousand kilometres from the South Pole, 36 athletes from 17 countries competed in a marathon last Friday, starting from a base camp in the southern Ellsworth Mountains.

"I think you need to be a little bit crazy," said one competitor, "but then again, I think its all relative. If you talk to some of the people competing in this race, theyve done some things that are far crazier."

Conditions for the race were favourable, and the athletes completed 1 laps of a course laid out around the Union Glacier base camp.

Competitors kept their skin covered for protection from the sub-zero cold, and strove to balance hydration requirements and sweating from exertion.

"I am going to force myself to run half the speed I would normally for the first few miles, then see how I feel and then hopefully pick it up at the end," said Elizabeth Chapman, a runner from the United Kingdom.

French runner Clment Thvenet, 37, was never challenged for first position and set an ice marathon record of 3:47:07.

Yvonne Brown from London, England, was the fastest of nine women, in 4:26:10.

Every competitor finished the 42.2-kilometre competition.