Evaluation of staplers design on comparision of subjective rating and electromyogram

The purpose of this study was to investigate the upper extremity musculoskeletal problems by fastening together sheets of paper with staples and effects of various types of stapler on subjective ratings and muscles activities. Nine participants performed 25 trials with five types of stapler (i.e. hand clamp type, desk type, press type L13, press type L11, press type L9) on five repetitions. Further, Electromyographic (EMG) for Extensor Carpi Radialis was measured by AcqKnowledge on Biopac systems (MP150, Biopac Inc., USA). In addition, the upper extremity musculoskeletal problems have been reported by questionnaire survey. Results of the questionnaire survey showed that most male use the stapler by single hand, however, female applied the stapler by both hands. Results of analysis showed that 28% participants reported the discomfort or pain on opponens pollicis and extensor digitorum tendons. Further, results of ANOVA showed that these were statistically significant differences between staplers. After Duncan multiple range test indicated that hand clamp type (47.4%), press type L13 (46.8%), press L9 (39.8%) and desk type (38.2%) were higher muscle activities than press type L11 (29.4%). Thus, stapler design and binding position has a considerable relationship, stapler size design and the palm of the hand parts are more consistent, relatively easy to use.