Around 40 sprinters, swimmers and weightlifters have spent the past four months in Abu Dhabi taking combinations of testosterone, human growth hormone, peptides and anabolic steroids -- all banned by events like the Olympics.The event, starting at 3.35pm (2235 GMT) and streaming on YouTube and Roku, has been denounced by athletics governing bodies and anti-doping agencies as dangerous and against the spirit of sport.But participants, lured by prize money of up to $1 million for beating world records, will include Olympic medallist swimmers James Magnussen, Cody Miller and Ben Proud, who have all taken drugs.Hafthor "Thor" Bjornsson, best known for playing "The Mountain" in "Game of Thrones," will try to break his own deadlift record.Former 100m sprint champion Fred Kerley will be one of the few athletes competing without drugs at the event.Max Martin, chief executive officer and co-founder, has predicted multiple world records will be "beaten," though the feats will not be officially recognized.Weightlifters Beatriz Piron and Arley Mendez surpassed world records in training, he told a press conference on the eve of the event."Hopefully they'll be able to do it tomorrow as well, and then we'll see a few more," said Martin.