Analysis of the Tony!™ Variable Geometry VDT Keyboard

Abstract

This study utilizes a variable geometry keyboard to analyze the optimal configuration for a split QWERTY-type keyboard. The measured criteria were muscle activity as measured by EMG and reported operator discomfort. A variable geometry keyboard, simultaneously adjustable in opening angle (yaw) and lateral angle (roll) was obtained. The upward slope (tilt) was preset at 10%. The study manipulated the keyboard geometry to assess the difference in musculoskeletal activity between using (1) a conventional, flat, linear keyboard; (2) a neutral, undeviated wrist position; and (3) two forearm positions that essentially eliminate pronation. Eight experienced subjects with no prior history of wrist injury or other pathology were tested. EMG activity of four relevant muscle groups was measured on each subject for each of the four keyboard positions. The study suggested an 18° opening angle and a 30°–60° lateral angle as optimal when compared with a flat, standard keyboard (they minimize objective EMG activity and subjective discomfort).