Get it right in the waxing shed and you can glide your way to Olympic glory. Get it wrong and the snow can turn to treacle.
In cross-country skiing, athletes must ensure they get their "kick wax" right in order to keep pace in the uphill stretches and former biathlete Jean-Marc Chabloz told Reuters there was no room for error.
"It is completely crucial, completely crucial," the four-time Olympian said as he demonstrated the basic techniques for waxing cross-country skis.
"You can't win a race with bad skis, it just doesn't work. Everyone is at their best, so it's small margins."
Chabloz, who now coaches student athletes at the Jamtlands High School in Sweden, expertly cleaned his skis and used a hot iron to spread a thin layer of glide wax before polishing them to a smooth finish.
For cross-country skiers and biathletes, getting the balance right is tough. They need to be able to ski as fast as possible across flat ground and downhill, but they also need a good grip to get them to the top of hills.
To achieve this, a stickier "kick wax" is applied to the ski in the area under and in front of the foot, while the rest is given a coating of glide wax.
But it is not just a case of what wax is applied where. There are hundreds of products on the market for different conditions.
"There's many parameters that have to be taken into account when waxing. The quality of the snow - is it rough or fine? It's the temperature, humidity and of course the distance," Chabloz explains.
The 50-year-old, who competed for Switzerland in Albertville, Lillehammer, Nagano and Salt Lake City, said he always got his waxing right at the Olympics, but others are not so lucky.
At the 2014 Sochi Games, both Norwegian relay teams performed poorly and the blame was laid squarely on the waxing team. And at a World Cup event in Ruka, Finland in November, it happened again.
"The skiers had good grip when they tested the skis, and bad grip when they skied the race. It's easy to explain - it was a waxing miss," Knut Nystad, who is responsible for waxing in the Norwegian team, told reporters.
For Alpine skiers and snowboarders, the requirements are different, with sharp edges often needed on their equipment to cut into the artificial snow and icy surfaces of downhill and slopestyle courses.
When waxing, teams must also take into account the fact that conditions can change during a race, which makes waxing more an art than a science.
But for Chabloz, the key is not to complicate things.
"There's a whole pile of waxing products out there, so you have to try to stick to something simple that you know, and then there's no big worries," he said.
(Editing by Peter Rutherford)
