For centuries, people have been pushing the limits of what they can do. But it seems that these days the limits are getting higher and higher. Normal waves are big enough for experienced surfers. They want big waves over 6 meters. Jumping from a 10-meter platform into a pour is no longer ________ enough for experienced divers. They want to jump from a ________ over 25 meters high. We imagine that people who do extreme sports love danger and are risk takers. But is this really true? Well, first, did you know that the most dangerous sports are considered to be cheerleading and horse riding? Of course, extreme sports are very dangerous. And if something goes wrong, it's possible a person won't ________. But people who do extreme sports have a lot of safety equipment which reduces the level of danger. In contrast, cheerleaders wear no safety equipment when ________ difficult moves. And horse riders aren't always able to control their horses' behavior. As a kayaker, Dr. Eric Brymer has first-hand experience of the extreme sports. He isn't ________ that extreme sports people are risk takers. His research shows they're careful people who respect the power of nature. They investigate the environment they're in and how the weather can change this. They use this knowledge to control the situation with ________, which reduces the level of danger and their level of fear. Dr. Brymer believes that people who do extreme sports are focused and ________ to succeed and not the ________ people we imagine. So why do people try to push the limits in sport? There're many theories, but let's look at three ideas. First, people usually do extreme sports alone. This means they cannot ________ on anyone else but themselves. Second, they set themselves a goal and work incredibly hard until eventually they reach their goal. Perhaps these are things that they can't do in their jobs, so look for them in sports. Finally, unlike everyday sports, extreme sports don't have ________ rules. Perhaps people who do extreme sports are looking to do something free from social rules. In this way, they feel their living life to the full.