HONG Kong triathlete Kim Isherwood leaves the territory tomorrow for the highlight of the season - the Ironman World Championship in Hawaii. The 35-year-old Hong Kong Sports Institute scholarship athlete stands sixth in the world rankings after finishing eighth in the New Zealand Ironman and ninth in the Japan and will be hoping to end the season in the top 10. ''It will be very, very hard to improve on sixth place because the competition is growing stronger all the time,'' said Isherwood, whose best finish in Hawaii is 19th, which she achieved last year on her way to ending the season ranked third in the world. ''There will be about 1,700 entries and over 500 in the women's section, so it is going to be an enormous struggle to hang to a top 10 place. ''I am very pleased to be in sixth place and it gives me a bit of leeway.'' The Hawaii Ironman, which will be held in Kona on Saturday, October 30, comprises of a 2.4-mile ocean swim, a 112-mile bike ride and 26-mile marathon run. Isherwood, who has been a full-time athlete since 1987, spent seven weeks in California during the summer training with American triathlete Terry Schneider, who finished last year ranked second in the world and fourth in Hawaii. The Hong Kong athlete also decided to miss the Canada Ironman event six weeks ago to make sure she was fully prepared for Hawaii. ''In the past, I have felt I have been hanging on going into the world championship, but now I am very excited about racing. ''I feel mentally quite fresh rather than wasted,'' Isherwood said of her change in preparation. Next season she will concentrate on the duathlon - run-bike-run - before switching her attentions to Hawaii, although she must take part in at least one triathlon to qualify for the World Championship.