Asia's largest adventure race, Action Asia Challenge, has proved hugely popular again, the field being completed twice as quickly as it was last year. The race will be held in Macau for a second consecutive year. The quota of 300 competitors was filled within three weeks of the registration process starting in early April. Last year, the same quota took six weeks to fill - a clear indicator of the sport's rapidly growing popularity. 'We have a very happy problem,' said race director Michael Maddess. 'Inquiries about the race keep coming in.' Some last-minute registrants might still be able to compete if there are no-shows on the race day, May 29, with organisers working on a contingency plan. To keep the weekend warriors in suspense, the race course will remain secret until the day of the race. The only information made public is that the race will start at Pousada Marina Infante in Taipa and finish at the Westin Resort in Coloane. The race will embrace various disciplines, including rock scrambling, inflatable kayaking, rope work, ocean swimming, trail running and stair climbing. An average person is estimated to take four to nine hours to complete the race. 'We hope participants and spectators can learn more about the natural scenery and various tourist attractions in Macau,' said Alex Vong Iao-lek, acting director of the Macau Sports Institute. The annual adventure race had been held in a different city for six years when it came to Macau last year. In 2004, a total of 269 participants from across Asia joined the race. Tourism chief Joao Costa Antunes said he hoped that Action Asia Challenge and its international media coverage would help attract more tourists to Macau. 'It will uplift Macau's international image,' he said. 'We have the legendary Macau Grand Prix, and then we have this.'