Five things about the Rio Olympics taekwondo competition

South Korean taekwondo fighter Lee Dae-Hoon (L) during a training session at a gymnasium of the Taereung National Training Center in Seoul on March 29, 2016 AFP PHOTO /

It may be the Korean martial art, but taekwondo has gone global. South Korea tops the all-time gold medal count since the event's debut in 2000, but its pre-eminence is gone. Rio features a veritable United Nations of medal favourites from China, Iran, Turkey, Britain, Spain and elsewhere.

Two athletes are chasing a record third taekwondo gold: Defending women's flyweight champion Wu Jingyu of China, and Steven Lopez of the United States. Wu is famed for her jarring "axe" kick, in which she whips her foot up above an opponent's head then brings it crashing down on their skull. It will be an incredible fifth Olympic appearance for Lopez, who at 37 is likely to be the oldest fighter in Rio but has not won gold since 2004.

The fierce attack cries of athletes will ring out in the Carioca Arena 3 in the main Barra Olympic Park from August 17-20. Gold medals are available in four weight classes for both men and women, and all matches will take place in a single octagonal fighting area measuring 8 metres (26 feet) across.

There is growing criticism that the sport's trademark spectacular twirling kicks to the head are being killed off by an electronic-sensor scoring system introduced in London 2012 to avoid judging controversies. Detractors say the system turns matches into drab "chicken fights" in which athletes repeatedly leg-jab at opponents' torso sensors to run up points, while avoiding exposing themselves with more daring offensive moves.

Authorities have counter-attacked with new rules and pomp in Rio to make the event more exciting. More points will be awarded for head kicks while points can be deducted if competitors fail to attack, and the new octagonal fighting area is meant to prevent athletes fleeing to corners to delay engagement. In a nod to boxing-style pageantry, athletes can now personally select the music that plays as they enter and, for the first time, can wear national colours instead of the usual white.