The effect of spine discomfort on the overall postural (dis)comfort: the case of vending machines

Currently, the word ‘comfort’ is often used in relation to the marketing of products such as chairs, cars, clothing, hand tools and even airplane tickets. The aim of this study is to investigate the influence of spinal posture on postural comfort perception while using a vending machine for purchasing food or beverages. A statistical sample of 20 healthy students performed the required tests, with each participant asked to take a product from three different vending machines (snacks, drinks and coffee). The subjects’ postures were acquired non-invasively using cameras. Angular detection was performed directly on photographs, using Kinovea ® software. Joint positions were used for the virtual-postural analysis, using DELMIA®. Digital Human Modelling (DHM) software. Postural comfort was evaluated in two ways: CaMAN® software, by University of Salerno (Italy), was used to calculate the objective comfort indexes, while a questionnaire was used to evaluate subjective comfort indexes. The results obtained from these simulations and questionnaires were compared, and a method to weigh the effect of the perceived spinal discomfort on overall postural comfort was proposed. These results reveal a good correlation between subjective perception and objective evaluation obtained through simulations, confirming the validity of the proposed method.