More than one in 10 athletes at the last two Winter Olympics were injured at the Games, according to research studies by the International Olympic Committee. When it comes to those injuries, some sports are much more dangerous than others.

For example, nearly half of the athletes who competed in aerial freestyle skiing at Sochi reported some kind of injury. Unsurprisingly maybe, almost no cross-country skiers did.

The studies, published in the British Journal of Sports Medicine after each Olympics, were relatively simple: researchers asked all countries’ national medical teams and the clinics in the athletes’ village to report every injury on a standard form. Any injury that was serious enough to warrant medical treatment was recorded, but they didn’t count pre-existing conditions. They recorded injuries incurred during both training and events.

Here’s what they learned.

1. The Winter Olympics is more dangerous than the Summer Olympics

“Probably one of the more striking things is that we see a very different injury pattern in Summer versus Winter Games,” said Dr. Willem Meeuwisse, a Calgary-based sports medicine specialist and one of the IOC’s researchers on this project.

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The reason: winter sports tend to be faster and athletes tend to fly through the air a lot more. This means more severe injuries, he said, because competitors are going at a high speed.

Twelve per cent of athletes in Sochi reported at least one injury, as did 11 per cent in Vancouver. This isn’t that much higher than the rates seen at the Summer Olympics (eight per cent in Rio and 11 per cent in London) but the winter athletes tend to be hurt more badly, Meeuwisse said.

“You would typically have injuries that are more severe in terms of the amount of damage to the tissue, so a fracture versus a bruise or a ligament tear versus a sprain.” Tweet This

2. Freestyle skiing and snowboard is pretty dangerous

More athletes got hurt during freestyle skiing or the various snowboard events than most other Winter Olympic sports. Nearly half of the aerial skiers reported an injury at Sochi, and 37 per cent of slopestyle snowboard athletes also reported injuries.

Bobsleigh is also dangerous. Eighteen per cent of bobsledders reported an injury at Sochi, similar to the rate in Vancouver.

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And although one person was killed during a training run in luge in Vancouver, injuries in that sport were relatively uncommon: just two per cent of competitors at that Olympics.

3. Weather makes a huge difference

“The last two Winter Games have been in relatively warm environments,” Meeuwisse said. And he thinks that weather conditions can have a big impact on the number of injuries in a given event, particularly in sports like alpine skiing or slopestyle snowboard.

This sort of thing is outside of researchers’ control, he explained, and can cause big fluctuations in injury rates between Olympics, just depending on what the weather was like the day a competition was held.

For example, top-level alpine ski courses are typically carefully groomed into a hard, icy surface, he said. “Because when you’re hitting the corners at those speeds, if the snow is soft at all, it just gives way. And you need it to be cold for that to happen.” If it’s not cold enough, the course could have problems.

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Competitors in Sochi spent a lot of time complaining about the “very sh-t” course conditions, as an Australian half-pipe coach reportedly put it. One Olympic snowboarder medal winner called the course “a little dangerous” and said it was leading to falls.

There might be good news here for athletes in PyeongChang: it’s actually cold there. It’s supposed to be the coldest Olympics since 1994.

4. Course design also matters

Meeuwisse thinks that the course design, particularly in new sports, also makes a difference in the injury rate. For slopestyle, a newly-added sport in Sochi where athletes ski or snowboard down a course and perform tricks off jumps and obstacles along the way, “what we learned there is the course behaved very differently for the men and women because of the speeds that they’re going. And the landing zones therefore changed.”

READ MORE: Sochi snowboarder injury prompts change to course layout

This is a big deal. “To land safely from aerial sports, you want to be landing on the steepest part of the hill. Then it’s kind of a glancing landing – imagine where a ski jumper would land. Versus if you land on a flat surface, then there’s way, way more impact.”

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Half of the women who competed in slopestyle ski at Sochi were injured, compared to 17 per cent of the men. The course, along with the weather, could be one reason why.