The Championships will feature a two-lap, four kilometres swim in Hefner Lake, the water reservoir for the American city, which has relaxed a no swimming rule for the event.

After the swim, athletes will then cycle 120km through a series of mildly undulating hills with the greatest challenge being the strong country winds.

The run course then consists of three laps of 10km each, which is staged at a flat and fast closed course at Hefner Lake.

Almost 20 women will take to the start in the fight for the world crown, with the event wide open as none of the last year’s podium are competing this year.

Among the field is Belarus' Hanna Maksinova, the current national champion, fourth in the European Triathlon Union (ETU) Long Distance European Championships this year.

She will be the one to beat, along with Sweden's Annie Thoren, who is the only athlete to have competed in last year's World Championship.

Hosts United States will have a strong squad with eight women listed, including promising triathletes such as Jennifer Spieldenner and Kathy Rakel.

In the men's race, France's reigning world champion Ciryl Viennot will be among the leading contenders. 

A very strong cyclist, Viennot has improved his performances and finishes in the longer distance races in the last couple of years.

He will be one of the most watched competitors, taking into account the host of new faces trying to grab their first long distance world podium.

Russian Nikolai Yaroshenko will be another candidate as he is in strong form.

Frenchman Sylvain Sudrie and Australia's Craig Alexander have both enjoyed many victories in mid-distance racing so should not be discounted.

Both elite races are due to take place tomorrow, with Para-competitions also to be held.