Ergonomics Study of Alternative Keyboard Designs

摘要

Commercially available alternative QWERTY keyboards, split and verticallyinclined, were studied to determine whether they are beneficial to keyboard users with respect to the risk factor for upper extremity work related musculoskeletal disorders, wrist and forearm posture. More than 90 clerical typists participated in the study and each subject was required to practice typing on the alternative keyboard for at least 10 hours prior to testing in the laboratory. When set up correctly, the three split keyboards reduced mean ulnar deviation of the wrist from approximately 10 degrees to within 2.5 of degrees of a natural position. This reduced one risk factor. A vertically inclined QWERTY keyboard in which the keyboard halves when tilted 30 degrees reduced average forearm pronation by about 20 degrees, bringing the forearm pronation by about 20 degree, bringing the forearm closer to an anatomically neutral position. Wrist position differed between the right and left upper extremities with the left wrist typically showing greater ulnar deviation and extension than the right wrist. No appreciable functional differences were noted in the kinematic of the wrist and forearm between alphabetic and alphanumeric typing tasks for either conventional and alternative keyboard. There were no appreciable differents in performance between conventional and alternative keyboard conditions after the subjects had practiced for 10 or more hours on the alternative keyboards.