Just as anything else, cheerleading has quite a history behind it.  In past times spectators cheered for runners in races held during the Olympics Games in ancient Greece.  In the 1860's students in Great Britain began cheering at competitive sporting events and the idea quickly spread to the United States.  At Princeton in New Jersey, in 1865 the first pep club was formed and they created the fist known cheer:

"Rah, rah, rah
Tiger, tiger, tiger
Sis, sis, sis
Boom, boom, boom
Aaaaaaaaaaahhhhhhhh!
Princeton, Princeton, Princeton!"

The history of organized cheerleading started in 1898.  The University of Minnesota  and complained he wanted a winning team, and spirit would take care of itself.  Everyone agreed to do something about it.  Then Jack Campbell, then a first year medical student, stepped in and became the fist ever cheerleader.  The next game Campbell led the crowd in a cheer that mad history.

"Rah, Rah, Rah
Sku-u-mar, Hoo-rah, Hoo-rah!
Varsity! Varsity! Varsity! Minn-e-so-tah!"

After this cheer, cheerleading  in the U.S. was born.  Believe it or not cheerleading was dominated by men in its early years, but when men went off to fight in World War II, the tables turned.  From then on more than 90% of cheerleaders were female.