Comfortable Pushing/Pulling Force Exertion for the Design of Consumer Products

The purpose of this study is to develop the measurement method of pushing/pulling force exertion for useful ergonomic design of consumer products, and to estimate the approximate force from body weights. In order to measure user-friendly pushing/pulling force exertion, maximal force exertion with one hand without varying posture is regarded as, "comfortable force" (CF). Thirty-four participants (17 males, 17 females, mean age 55.1 yrs, SD 15.5) performed CF exertion and maximal force of free posture (MF) with two types of different height (elbow height and high height (shoulderflexion 135 degrees) respectively. The force ratio of mean values of CF to that of MF ranged from 0.25 to 0.29, and the force ratio of mean values of elbow height to that of high height ranged from 0.57 to 0.61. Concerning the dispersion of data of force exertion, in all of the measurement conditions, coefficient of variations (CVs) of CFs were smaller than CVs of\´MFs. Moreover, the CVs of those data normalized to body weights, went smaller. On the whole, the CF of pushing/pulling of elbow height was approximately 0.1 of body weight.