What makes somthing a sport.

What are sports? Baseball, Football, Basketball, Hockey, and soccer are the main five sports that come up when talking about popular sports. But these are not the only sports out there! People look at sports like Golf, Tennis, cheer leading, and swimming like they are just games or activities that people do for fun. but in retro spec these are sports no matter which way you look at it. a sport is something that lets people either show off there athletic ability or there technique and knowledge of the game that they decide to play.As a Tennis player i hear all the time " oh aha ya he plays tennis.. its not a real sport" but trust me when i say tennis is one of the hardest sports i have ever played in my life. not only do u need an excessive amount of endurance to play matches that are some times 3-4 hours long, but you also need the technique and the knowledge to know how to hit the ball in certain ways and when you need to hit it and where you need to put it. so yes tennis is a sport so are almost all of the other "games" that people use athletic ability.