Somewhat more than 50 per cent of computer operators complain of problems in the neck, shoulders or arms. A possible source of such problems may be manipulation of the mouse. Women are more susceptible than men, possibly due to their smaller physical size and muscle power. With the mouse placed to the side of the keyboard, narrow-shouldered computer operators must lift their arm and turn it sharply outwards. It is preferable to place the mouse within the span of the shoulders and rest the entire forearm on the desk. A shorter keyboard might be the answer for narrow-shouldered people.