On Sunday, 19-year-old Hui Yau-chiu will tackle the most gruelling sporting event of his young life - the Action Asia Challenge Hong Kong 2006. Hui and his partner, Tam Wing-chung, 22, will pit their talents against 340 dedicated adventure racers from around the region - the highest number of entrants ever. The race will take place at a new course in the New Territories. Adding to the suspense, the course will remain a secret until the day of the race. Hui's love of orienteering began when he made friends with a senior student at his secondary school five years ago. 'A senior introduced the sport to me when I was a Form One student. I have loved it ever since. It is a very challenging sport where you can improve your techniques each time,' said the Form Six student at Queen's College. As a fourth former, Hui represented Hong Kong at the Junior World Orienteering Championship 2005 in Switzerland. That year, Hui and his teammate won the Youth Adventure Race 2005. More success was to follow, with Hui finishing second runner-up at the Wilson Trail Race in October this year. Referring to Sunday's race, Hui said he and his partner would be a match for anybody in physical strength but lacked experience. 'I've been running 10 kilometres every day after school at Victoria Park. My partner and I also train on mountain trails. We've been very busy, but we will have to start practising swimming soon,' he said. The challenge, which involves a minimum racing distance of 35km, is expected to take the 170, two-member teams between five and nine hours to complete. The race will embrace various disciplines, including mountain biking, trail running, kayaking, swimming, abseiling, and rock climbing. The overall champion and first and second runner-up will share 210,000 Asia Miles between the six members, as well as receive Suunto watches. The top three teams in each category will receive trophies. Sunday's race is the fourth in the 2006 Asia Miles Action Asia Series. The event, which is being held in Hong Kong for the ninth time, will begin at 7am.