The creation of modern “kickboxing” from the roots of traditional martial arts, like Karate, is an interesting topic. Many of the fans of kickboxing don’t know where it came from. Depending on the style, there are two main origins.
In the U.S. in the 1960′s Karate practitioners developed what they called full-contact Karate. Ironically, this competition style limited the techniques that could be used, but was considered “full-contact” in comparison to the safer point sparring that many Karate schools practiced.The full explanation can be found at http://totalcombatfitness.wordpress.com/2011/05/08/what-is-muay-thai-2/ It was in this style that famous kick boxers like Bill Wallace, Don ” The Dragon” Wilson, and Chuck Norris built successful careers.
Termed full-contact Karate, or American kickboxing, the rules prohibit leg kicks, as well as knee and elbow strikes. Competitors normally wear long pants, gloves and protective pads on their feet. It is essentially a combination of the techniques from traditional Karate sparring and western boxing, with a rule set that protects fighters from avoidable injuries.
The other style that is commonly referred to as kickboxing is Muay Thai. Muay Thai is a traditional martial art style from Thailand. The ring sport version has certain safety measures but allows far more techniques than American kickboxing with less protective gear.
Muay Thai fighters are banned from headbutting or biting and from striking their opponent in the groin. Unlike American kickboxing, however, they can kick to the legs, strike with elbows and knees and hold on to the opponent while striking. Most competitive Muay Thai involves gloves but no pads on the feet. Both styles are judged on a basis of points accumulated from strikes and an automatic win from a knockout.
All that being said, American kickboxing evolved from Karate as an exciting, but still moderated, form of competition, similar to western boxing. Kickboxing is also a term used to refer to Muay Thai which is unrelated to traditional Karate.