AN ERGONOMIC DESIGN AND PERFORMANCE EVALUATION OF HANDY SCANNERS BY MALES

This paper describes the results of an investigation of the difference in performance, posture used, strain on forearm musculature, and subj ective ratings of three handy scanners (models A, B and C). Both model s A and B were scanners on the market, Model C was developed for valid ation, The gripping posture of the three models is distinct both in th e anatomical and functional sense, Work with model A requires a thumb- forefinger side grip which induces an ulnar deviation angle; work with model B requires a thumb-finger grip; work with model C requires a th umb-finger-palmar grip, Performance evaluation of scanner models A, B and C on different scanning tasks (with and without stitch) using diff erent resolution modes (100 and 400 dpi), indicated that using the pro posed model C resulted in a 13% higher success rate, a 14% shorter com pletion time, the smallest self-selected working area, least strain on the forearm muscles, and highest subjective ratings among the three, Model C appeared to provide the greatest opportunity for delicate adju stments of posture in response to the activity of the skin receptors, justifying the ergonomic input into the design.