Design and Assessment of Ergonomics of Hand-Powered Pruning Shears Based On Gender-Specific Operating Strategy

摘要

The present study investigated the biomechanical and physiological loads when working with pruningshears of varying design. The objective of this study was to find usability issues on conventional pruningshears and integrate ergonomics into the design process to improve users’ safety and health as well asperformance. Effects of pruning shear design, gender, and hand size on muscle activities, grip forcedistribution, wrist deviations, and gender-specific operating strategy were studied in six male and sixfemale participants while cutting wooden dowels with pruning shears. Three types of pruning shears wereused, one conventional and two modified, either with a rubber grip-padded, or with a thumb grip attachedto the upper handle. The results showed that (1) the two redesigned pruning shears minimized pressures onsome critical hand regions and improved muscle activities, grip force distribution, and wrist deviations and(2) a large degree of wrist extension, greater use of the extensor digitorum (ED) muscle, and excessivesqueezing force were women’s operating strategies to overcome their biomechanical disadvantages due tosmall hand size and less muscle strength during pruning work. Based on this finding, it was concluded thatconventional pruning shears have potential design problems related to musculoskeletal disorders (MSDs),and therefore ergonomic interventions should focus more on variations in user anthropometry andphysiological responses.