In our time, when a large development was the culture of leisure, sports and watching them have become popular entertainment for the spectators and professional activities for athletes.
Professional athletes make a lot of high-level fees, as well as receive income, advertising various products and become celebrities - sometimes in a narrow (or not) among the fans and sometimes even among the majority of the population.
To control what is happening in professional sports are formed general and highly specialized organizations and associations that bring together athletes, coaches, judges, and sometimes the fans.
The fact that the sport has become a business and a source of well-being, strongly affect the essence of competition. Due to the requirements of convenience, entertainment or sports refereeing rules change frequently.