Muay Thai or Muaythai, sometimes referred to as Thai boxing, the Art of Eight Limbs or the Science of Eight Limbs, is a Thai martial art and full-contact combat sport that uses stand-up striking, sweeps, and various clinching techniques. The name “Art of Eight Limbs” refers to the combined use of fists, elbows, knees and shins. Muay Thai became widespread internationally in the late 20th to 21st century, when Westernised practitioners from Thailand began competing in kickboxing and mixed-rules matches as well as matches under Muay Thai rules around the world. The professional league is governed by the Professional Boxing Association of Thailand, sanctioned by the Sports Authority of Thailand.