JAN Darmody blames her new career on tennis elbow and the MacLehose Trailwalker. When Mrs Darmody, a tennis-buff, decided to find a solution to her nagging ailment, she canvassed other players. She got more than advice. ''They ended up complaining about what they couldn't find here. Sport products like lubricating cream that wasn't as messy as petroleum jelly, grips for rackets that didn't slip when your hand got sweaty, sun visors with washable sweat bands.'' The litany of needs did not stop when she left the tennis club. Her husband, an avid tri-athlete and hiker, was preparing for the MacLehose Trailwalker last November. He and his friends were looking for miner's head-lamps, small enough to fit in a back-pack. But no luck. One fellow-walker solved the problem by affixing a torch to his visor. But studying the slope of his nose during the pre-dawn assault of the rocky path was worse than the rocks. Another hiker with tender knees lamented that he could not find a walking stick that collapsed. She started taking mental notes. Hikers, she learned, had similar needs to tri-athletes and marathon runners who trained during the summer - keeping well-hydrated. Finding a way to carry water that would free the hands was a commonly heard request. One girlfriend, a marathon runner, had specific designs for a water bottle belt. It had to hold two bottles without impeding the arm swing. Mrs Darmody became a depot for runners' catalogue of requests. All her 11-year old son wanted was a way to stay cool while playing outside. Over a period of months Mrs Darmody became a magnet for catalogues and a walking diary of sport enthusiasts' complaints. She devoured advertisements in sports magazines and speciality brochures. When an item sounded like a solution, she ordered it, one piece at a time. ''It got expensive. I was ordering everything retail.'' Every complainant became her guinea pig. Products were road-tested according to interest - her husband's Trailwalker team, joggers and hikers around the neighbourhood and the coaching staff at her tennis club. ''Some of the stuff turned out to be junk,'' she recalls. Like the water bottle with the freezable top. It was supposed to keep liquids chilled for hours. ''It leaked.'' The former marketing executive in real estate from California says she has always been interested in gizmos and gadgets. When the family moved to Hong Kong three years ago, she worked part-time as a fitting model. ''The money was good but it was brainless work,'' Mrs Darmody said. ''I got bored.'' Discovering sources and finding products that worked became a gratifying pursuit. Among the finds that rated the thumbs-up from the testers, were: Cool Sports Neck Wrap: a nylon scarf with a velcro-sealed pocket, containing eight cubes filled with freezing agents. The scarf help reduce core body temperature. Tenex Elbow Shock Absorber: a bracelet filled with high-density liquid mercury to absorb and dissipate shockwaves. Gemini Torsopac: a webbed belt that carries two insulated holsters, each with a water bottle. It also features side mesh pockets and a centre compartment. Digi Sport Lens: a floatable sport visor from France. It features with a wrap-around lens that is contoured to the face. Telescoping walking sticks: one model features ski-pole grips and removable baskets. It adjusts from 67 to 145 centimetres at a twist. One model features a compass. When the demand dictated ordering wholesale, she knew she had found a niche market. And when she organised the family holiday around the date of the National Sporting Goods Show in Chicago, she knew she was in business. ''Living with quantities . . . 200 of this, 250 of that . . was an incentive to move the inventory or move out of the flat. ''I had to focus my business and my buying.'' Any product that contributed to comfort, safety and performance in a sport was the deciding factor. Fashion was not a consideration. Sports Specialities, her four-month-old business, is run from a spare room in the family's Chung Hom Kok flat. Life has changed. The flood of in-coming faxes from the United States keeps her up nights. So does learning the new accounting software. The home computer has been replaced by a more powerful one and the size of the freight shipments forced her compact car into early retirement. And tennis elbow? ''That's gone,'' said Mrs Darmody, pointing to an elbow shock absorber, wrapped in plastic. ''Need one? I've got 200 in my bedroom.'' For more information, contact Sports Specialties: Tel. 813-9439. Fax: 813-9506.