We combined the most dangerous parts of every sport—this is the result

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Playing sports can teach teamwork, boost self-esteem, and improve health, but they’re not all fun and games. The Centers for Disease Control and Prevention estimates there are about 8.6 million recreation-related injuries each year, ranging from hand fractures in boxing to head trauma from falling off horses. Few of these are fatal, but they can quickly turn even the friendliest match into a bloodbath. By analyzing the millions of incidents cataloged in the National Electronic Injury Surveillance System in 2018, we’ve pinpointed the most common—and surprising—athletic boo-boos and combined them into one über-dangerous event.

Basketball

Dribbling down the court can have consequences. Hand and finger fractures are common, but the real threat comes from footwork. Sidestep maneuvers and sudden stops contributed to 77,023 ankle sprains and 25,222 knee sprains in a year. And watch out for flying elbows: Basketball is the leading cause of athletic eye injuries, boasting 2,638 bruised peepers.

Biking

Bicycles pose a major threat to your nethers. The molded plastic seat puts pressure on muscles, bones, and nerve endings over long-distance rides. In a crash, it can even impale its rider; in a single year, 1,419 people sustained damage to their private area while biking, like pelvic fractures and penetrating rectal wounds. Falls also make two-wheelers a leader in dental damage.

Football

Tossing the pigskin resulted in 26,478 concussions—a form of brain damage from rapid motion inside the skull—over a year. These incidents can occur at any level, from youth clubs to the NFL. Most symptoms resolve within a few weeks, but some doctors now worry repeated trauma could have long-term consequences for cognition, memory, and emotional stability.

Cheer

In just 12 months, cheer resulted in 3,225 head traumas and 2,354 concussions. Most occur during stunts, when athletes climb human pyramids and propel themselves into the air. Unlike in other sports, where damage occurs during competitions, these catastrophes tend to happen in practice during the countless repetitions required to refine gravity-defying feats.

Playgrounds

An estimated 45,225 folks hurt themselves on these attractions, mostly by falling from the monkey bars. Flying off swing sets and slides contributed to thousands of additional head injuries, lacerations, and lower-arm breaks. Danger can even lurk in your own backyard: Home trampolines caused 14,424 sprained ankles and 8,815 fractured lower legs in 2018.

Swimming

Acute otitis externa (better known as swimmer’s ear) isn’t the only pool-related problem. Paddlers reported 70,435 cases of ear damage in one year. These range from otomycosis, a fungal buildup caused by polluted water, to surfer’s ear, in which prolonged exposure to cold fluid causes bone spurs to grow in the canal. Left untreated, both can lead to permanent hearing loss.

This story appeared in the Summer 2020, Play issue of Popular Science.