Which Olympic Sport Is Hardest on the Body?

Understanding the injuries and the toll they can take

Athletes are competitive by nature, so when they get together for a massive sporting event like the Olympics, there’s likely a bit of good-natured one-upmanship when it comes to whose event is the hardest.

Yes, it’s a bit of a parlor game, and everyone has an opinion. But while difficulty is somewhat subjective, there are ways to stratify sports that could start to isolatinge which sports take the biggest toll on the body–by the highest number of injuries racked up by athletes, by what types of injuries they develop, and by which injuries tend to have bigger impacts on their long-term health.

That data, unfortunately, is not as complete as it could be. The U.S. Olympic and Paralympic Committee (USOPC) runs several national training centers, but not all sports take advantage of them. And the USOPC doesn’t track overall injuries experienced by Team USA athletes since those are collected by individual national sport organizations—USA Gymnastics, for example, or USA Rugby. Still, during the two weeks each of the Olympic and Paralympic Games, the USOPC does have the entire universe of U.S. athletes competing in 32 sports under its purview, and similarly, the International Olympic Committee (IOC) also tracks injuries during the Olympic Games and reports them in the British Journal of Sports Medicine.

Sports physiologists divide sports into two broad categories: those that involve direct physical contact (—the combat or collision sports), which include those involving dangerous pieces of equipment such as bikes or horses—and can cause traumatic injuries, and those that test the body’s endurance skills, which and are more likely to cause chronic, overuse problems. Injury information collected by the IOC during the Olympic Games is biased toward traumatic, or acute, injuries because “overuse injuries tend to happen in the buildup to the Games or after the Games,” says Dr. Jonathan Finnoff, chief medical officer of the USOPC. According to the IOC, at the last Summer Olympics in Tokyo, the sport with the highest injury rate was boxing, with nearly 14% of boxers requiring medical care during the Games, followed by 12.5% of sport climbers and 11% of skateboarders. “Speaking generally, during the Olympic Games, the high-speed, high-force and big-air or combat sports cause more injuries,” says Finnoff. During the 2016 Summer Games in Rio de Janeiro, BMX bikers topped the list at 38%, followed by boxing at 30%, mountain-bike cycling at 25%, and water polo and rugby both at 19%. Among Team USA athletes, more than half of rugby players experienced injuries at recent Summer Games, while about half of wrestlers and divers did.

But that doesn’t mean that swimmers or marathon runners are in the clear – chronic injuries due to repetitive motions in their sports are more likely to cause problems that may not appear until years later, because they are harder to identify and more challenging to treat. “Traumatic injuries like muscle tears and broken bones are fixable,” says Dr. Alexis Colvin, professor of sports medicine at Mount Sinai, “whereas chronic overuse issues sometimes linger and aren’t necessarily something that can be fixed.”

Both types of injuries can have long-term health effects, though it’s hard to know specifically what impact training and competing at the Olympic level have on the body, since no sports group collects detailed information on these athletes after their competitive careers are over. Research continues to show, however, that any acute injury such as a broken bone, muscle tear, or damage to the joints can cause problems down the line. “Repetitive damage can lead to higher and higher incidence of long-term bad outcomes, including severe arthritis and even needing early joint replacement,” says Finnoff.

Putting aside injuries that happen during competition, if you consider sports by how many different body parts are at risk of being injured at any one time, Dr. Robert Gallo, a professor of orthopedic sports medicine at Penn State University, says one sport stands out for its potential for both acute and chronic problems. “I personally think that gymnastics combines both,” he says. “You can land on your head, or land on your foot, and they also have a lot of chronic injuries that people don’t see a lot. Every single joint in gymnastics is subject to problems.”

Add to that the fact that most gymnasts begin training at an early age, and the toll on the body is pretty substantial. “Gymnasts have to have a body awareness before they go through puberty, so that’s one reason they start early,” says Mary Barron, associate professor of exercise and nutrition at the Milken Institute School of Public Health at George Washington University. “If you’re starting a sport when you are 2 years old and participating until you are in your 20s, that’s a lot of wear and tear on the body.”

But that higher risk doesn’t mean injuries are inevitable. “We talk about the body of elite athletes in training in terms of green, yellow, and red lights,” says Dr. Matthew Silvis, director of sports medicine at Penn State University, referring to the amount of pain athletes feel and their ability to finish and recover from daily workouts. “Green means you feel amazing and can continue training with no issues. Red means you can’t finish your workout for the day because you’re in too much pain, and it doesn’t get better by the next day. Most athletes live in yellow—they feel OK even though they hurt and ache while they are working out, but they can complete their workouts and they don’t feel worse the next day.” Knowing when that yellow shifts into red is key to preventing injuries, and keeping the athlete training at optimal levels for as long as possible.

For distance runners, for example, increasingly painful workouts veering toward the red zone might mean switching from outdoor running routes to an underwater treadmill to reduce pressure on the joints, or concentrating on aerobic exercises to maintain that aspect of their performance while reducing time spent pounding on the muscles and bones.

Barron notes that constant improvements in technology also help athletes and their coaches to better protect against injuries. Video of how basketball players land after jumps, for example, can help identify those who tend to overflex their knees beyond their toes once they hit the ground, which can increase their risk of ACL injuries. Strengthening other muscles to avoid that overflexing can go a long way toward avoiding those injuries.

And it’s not just technique that can play a role in avoiding injury—paying attention to things like nutrition and sleep can also be important, especially “to restore the body and give it the best chance of not being injured,” says Silvis. “The model for sports is to be active for life,” says Barron. “The information we gain every year changes what we do the next year, so the way we take care of and try to avoid injuries is very different now than it was four years ago. And that will help them to stay healthier beyond their careers as Olympic athletes.” Which still doesn’t mean any of this is easy.