Cross-country skiers change their skis mid-race. Why?
If you've been watching cross-country skiing at the Winter Olympics in PyeongChang, you'll likely have noticed that the competitors change skis midway through the race. Perhaps you're wondering why they do that.
The first thing you should know is that cross-country skiing requires skiers to engage in two different types of skiing altogether. There's the "classic style," where skiers are either propelling themselves in a straight line or using a herringbone walk—basically walking like a duck, with the toe of the ski pointed out—to go uphill. The second type of sking is the "skate style," where skiers move their legs diagonally in a similar method to speed skaters.
These two distinct styles require different types of skis. So each competitor has one set of skis for the classic style and one for the skating style. When they change skis, it's after the classic portion is finished and before the skate portion starts.
If you want to know more about cross-country skiing, we've got you covered—here's a Rookie's Guide to get you up to speed on one of the most grueling sports of the entire Winter Olympics.