Mixed martial arts (MMA) is a full contact combat sport that allows a wide variety of fighting techniques and skills, from a mixture of martial arts traditions and non-traditions, to be used in competitions. The rules allow the use of both striking as well as grappling techniques, both while standing and on the ground. Such competitions allow martial artists of different backgrounds to compete.

No-holds-barred reportedly took place in the late 1880s when wrestlers representing a huge range of fighting styles, including various catch wrestling styles, Greco-Roman wrestling and many others met in tournaments and music-hall challenge matches throughout Europe. In the USA the first major encounter between a boxer and a wrestler in modern times took place in 1887 when John L. Sullivan, then heavyweight world boxing champion, entered the ring with his trainer, Greco-Roman wrestling champion William Muldoon, and was slammed to the mat in two minutes. The next publicized encounter occurred in the late 1890s when future heavyweight boxing champion Bob Fitzsimmons took on European Greco-Roman wrestling champion Ernest Roeber. Reportedly, Roeber suffered a fractured cheekbone in this bout, but was able to get Fitzsimmons down on the mat, where he applied an armlock and made the boxer submit.