WHEN Dermot Reeve decides to do something there are no half measures. As a teenager in Hong Kong he decided he wanted to be a county cricketer in England - and went on to play for Sussex, Warwickshire and England. Now, aged 30, he has decided to spend the English winter coaching Hong Kong in the build-up to the International Cricket Council Trophy in Kenya next February. There will be no half measures from Reeve when he takes up his three-month contract in December and he expects the same kind of commitment from the players. This means a whole new outlook for the territory's weekend cricketers, who, in four months' time, will be up against world cricket's B-ranked nations for one of three qualifying places for the 1995 World Cup alongside the nine Test-playing countries. The Hong Kong Cricket Association feel Reeve is the ideal man for the job - someone who knows the cricket scene in the territory and who knows what it takes to get to the top. After signing his contract at the Kowloon Cricket Club last Thursday, Reeve outlined the work ahead for himself and his players. ''I have had a meeting with the Hong Kong captain, Pat Fordham, and told him what I expect from the players over the next four months,'' said Reeve, who represented the territory in the 1982 ICC Trophy in England. ''In that time the players have to get very serious and start to make sacrifices to their lifestyle. They must change their lifestyle, in fact, and work extremely hard in turning themselves into athletes as well as cricketers. ''We have already run a fitness test and there is a very wide range of fitness levels among the players at the moment. ''In the next month they will be building up their aerobic fitness and will be working on mobility, watching their diet and getting themselves into good shape. ''They will also do three strength sessions a week in a gym or at home. I am asking them to devote one hour three days a week. That is the sacrifice but it is not a huge one to make if people want to play in the World Cup against England, Australia and the West Indies.'' Reeve handed out fitness programmes and advice on nutrition and mobility to the players before leaving Hong Kong for a 10-week holiday in Australia. He will return to the territory on December 22 and have six weeks with the 16-strong squad before heading for Kenya in early February for the 20-team ICC Trophy, which runs from February 12 to March 6. The Warwickshire captain and match-winning all-rounder said the ''S factor'' would be crucial in his work. ''The three Ss are suppleness, stamina and strength,'' he added. ''The fitness programme will change from stamina to speed when I come back to Hong Kong on December 22 in order to improve reflexes. ''Fitness is so important to play one-day cricket. I know because I have gone from an average county player into the Test team and the main thing I worked on was my fitness - it lifts your whole performance level. ''If you go in to bat and score a hundred and your team gets 240, that is not necessarily a winning total. You need a good fitness level to then go out and field well or bowl six overs that may be vital. ''A lot of the players here who play in the Saturday League do not look for quick singles to keep the scoreboard ticking over. They know they will get a bad ball they can punish so are not looking to take the quick single - they'd rather keep strike and hit the next two for four. ''Cricket is habit-forming and you have got to practise good habits until they become second nature.'' Reeve also hopes his big-match temperament will rub off on to the Hong Kong players. In a remarkable career, he has won two Man of the Match awards in NatWest Trophy finals and, only last month, steered Warwickshire to an amazing last-ball victory over Sussex in the Lord's showpiece. And at last week's Hong Kong International Sixes, Reeve pulled England out of trouble in the final with an unbeaten 31 to help them to a three-wicket victory over Sri Lanka. ''It will also be my job to get the players mentally focused on a big match,'' said Reeve. ''You want people to be performing at their optimum level. It's an individual thing on match days because you don't want people to get too stressful or over-confident. ''You can never be too keen in training but you can, in a way, on match days. You must never lose sight of the fact that you must enjoy the day.'' Reeve, who will be involved in the selection of the 16-strong squad and of the teams in Kenya, concluded: ''The players have got to believe, like I do, that we can go to Kenya and win through to the World Cup. ''They have got to want to do that. There is no point going if you do not believe it is going to happen. ''The talent is there because I've seen it at two Hong Kong Sixes competitions. ''It is now about working on the belief and the professionalism.''