What isthe hardest sport in the world? Some people say it's boxing (拳击), because boxing is dangerousand boxers have to be strong and fast. Other people say the hardest sport issoccer.

    However,most people say the hardest sport is the triathlon (三项全能运动). A triathlon is a race thatincludes three sports. First, racers swim. After that they ride bicycles andfinally they run. In the most common triathlon, racers swim 1.5kilometres, bike40 kilometres, and run 10 kilometres. The winner is the person who finishes therace first.

    There isanother kind of triathlon too. It is called the "Ironman Triathlon (铁人三项)". This triathlon is muchlonger. People who finish this triathlon are called "ironmen" or"ironwomen". This is because these people are so strong that theirbodies are just like iron (铁).

    In thepast, there were other races including three sports. However, they didn't usethe word "triathlon". That word was first used to describe a race inCalifornia in 1974.

    Triathlonracers have to train very hard for their races. Many of them swim and run. Alot of people also do things like yoga (瑜伽). They have many different ways to prepare, but they all have thesame goal. They want to be in perfect shape.

    To be anironman or an ironwoman, you have to be strong and smart. You should know howto save energy during the race.