What is the hardest sport in the world? Some people say it's boxing (拳击), because boxing is dangerous and boxers have to be strong and fast. Other people say the hardest sport is soccer.
However, most people say the hardest sport is the triathlon (三项全能运动). A triathlon is a race that includes three sports. First, racers swim. After that they ride bicycles and finally they run. In the most common triathlon, racers swim 1.5kilometres, bike 40 kilometres, and run 10 kilometres. The winner is the person who finishes the race first.
There is another kind of triathlon too. It is called the "Ironman Triathlon (铁人三项)". This triathlon is much longer. People who finish this triathlon are called "ironmen" or "ironwomen". This is because these people are so strong that their bodies are just like iron (铁).
In the past, there were other races including three sports. However, they didn't use the word "triathlon". That word was first used to describe a race in California in 1974.
Triathlon racers have to train very hard for their races. Many of them swim and run. A lot of people also do things like yoga (瑜伽). They have many different ways to prepare, but they all have the same goal. They want to be in perfect shape.
To be an ironman or an ironwoman, you have to be strong and smart. You should know how to save energy during the race.
