Abstract
To design comfortable and efficienthand tools, an objective measurement such as using surface electromyography (sEMG) is required, where the ergonomic design tries to find the most optimal and most fit design of hand-tool that doesn't cause stress on the hand muscles. The hand tool design optimization will be demonstrated in this study on designing shampoo bottles, where the design of bottle and its compatibility with the slippery watery area, in addition to the aesthetic considerations are important issues that must be taking by the manufacturers concerned with such industries. Six different designs of shampoo bottles, as outcomes of industrial design graduation project in the department of Industrial design at our university, were used in this study. The new designs, together with other traditionally bottle designs, were evaluated in simulated shampoo pouring task in the laboratory. Several important parameters extracted from the sEMG signal in both temporal domain and frequency domain provide useful information about the tested designs. Twenty healthy university students (10 males and 10 females; mean age of 21 ± 2 years) were included in this study. Each subject was asked to handle the bottle and simulate the shampoo pouring activity in gentle and delicate manner using the grasp pattern that is found most comfort for him/her. Muscular behavior during bottle holding and shampoo pouring tasks show that male and female have different preferences in dealing with different bottle design, where male have less hand stress with designs that achieve the best fit of their full hand, while female have less hand stress with designs that achieve the best fit of their fingertips, and therefore, the end-user gender must be considered in designs of such industries.