THE HARDEST SPORTS ON THE BODY

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 oneupmanship over whose event is hardest.

- ALICE PARK

But while difficulty is somewhat subjective, there actually are ways to start isolating which sports take the biggest toll on the body-by the highest number of injuries racked up by athletes, for example, by what types of injuries they develop, or by which injuries have bigger impacts on their long-term health.

That data is not as complete as it could be. For one thing, the U.S. Olympic and Paralympic Committee (USOPC) doesn't track overall injuries experienced by Team USA athletes since those are collected by individual national sport organizations-USA Rugby, for instance. Still, during the Olympic and Paralympic Games, the USOPC does have all U.S. athletes under its purview, and similarly, the International Olympic Committee (IOC) tracks injuries during the 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 can cause traumatic injuries, and those that test the body's endurance, which are more likely to cause chronic problems. Injury information collected by the IOC during the Games tends to be biased toward traumatic, or acute, injuries, says Dr. Jonathan Finnoff, chief medical officer of the USOPC.