Editor’s Note (02/08/18): Scientific American is re-posting the following article, originally published August 1, 2012, in light of the 2018 Winter Games which begin on February 9 in PyeongChang, South Korea.

We rarely see it happen on television, but one in 10 Olympians will get hurt during the games, if the past is any guide (left). About three quarters of the injuries occur during some phase of competition and one quarter during warm-ups or on-site training, according to Lars Engebretsen of the University of Oslo in Norway, who compiled the data. Summer athletes tend to ruin their legs; winter athletes bang their heads (below). The causes vary greatly: collisions (soccer), stick strikes (field hockey), high-speed wipeouts (bobsledding). The damage leader—snowboard cross—involves frequent contact between boarders in a free-for-all downhill race. Sailing is nearly harm-free. Engebretsen says injury rates in most professional sports, such as football and soccer, are higher, although data are inconsistent.