The split keyboard: an ergonomics success story (original) (raw)

2008, Human Factors: The Journal of the Human Factors …

BACKGROUND For the past 50 years, there has been increasing recognition and evidence that long hours of keyboard use are associated with hand, arm, shoulder, and neck pain and upper body musculoskeletal disorders (Gerr, Monteilh, & Marcus, 2006). These problems are related to work organizational issues (e.g., hours of computer use per day, job demands) as well as sustained awkward postures, such as shoulder elevation, wrist ulnar deviation, and head rotation. Some of these postural demands, such as ulnar deviation, wrist extension, forearm pronation, and shoulder abduction, are related to the design of the conventional, straight keyboard. There has been a long-standing interest in determining whether the split keyboard designs reduce these postural demands and reduce upper body pain in keyboard users. The conventional, straight QWERTY keyboard design is based on the 1878 patent of Christopher Latham Sholes (U.S. patent 207,559). The keys are arranged in four staggered but straight rows, as shown in Figure 1. In 1915, F. Heidner released a patent with split keyboard designs (U.S. patent 1,138,474), which were to enable the operator to write in a less cramped position, but the first research on split keyboards did not occur until the 1920s. In 1926, Klockenberg conducted a series of experiments to assess subjective strain in the forearms of typists. He suggested that the keyboard be divided into two halves (one half for each hand) and that the halves be laterally inclined to reduce the muscle tension in the shoulders and arms. These changes were expected to lead to less muscular strain in the typists and to better typing performance. He wrote that although these strains may be small, they add up to considerable magnitude over many hours of keyboarding (Kroemer, 2001). There was relatively little work on the split keyboard concept until the work of Kroemer in the 1960s. Definitions for positioning the two halves of a split keyboard are presented in Figure 2. The angles are based on a plane through the top of the