Remaining seated for extended periods increases the risk health issues and discomfort perception. Consequently, the seat-pan design is crucial and could be mainly influenced by two factors: pressure distribution and seat contour. For seat pan discomfort, the lower average pressure is accompanied by less discomfort. Moreover, a seat contour with a large contact area is correlated with more comfort. Thus, a shaped cushion had been accurately designed (Virtual Prototype) and realized (Physical Prototype) aiming to translate the pressure distribution due to interaction between seat and buttock in a geometric shape, suitable for the international population (including P5 females and P95 males). With this shape, the pressure should be more uniform and lower, the contact area at interface bigger, and the perceived comfort higher. Both Virtual and Physical Prototype design had been described in this paper through a repeatable and straightforward approach. Also, experiments had been performed to validate the hypothesis through a comparison with a standard flat cushion. Results showed the goal of the design had been reached: the shaped cushion scored less pressure distribution and higher contact area than the flat cushion.

Various aspects related to comfort are described in this special issue. Some papers are focused on the environment, like smell, temperature, light, acoustics, space and some on an artefact touching the human, like the floor angle, the seat, a bed and light. However, in this special issue also topics like modelling and behavior get more attention.

This study aimed to analyse the discomfort threshold (that could be linked to sensitivity or sensation) of different regions in hand and elbow to support hand-held devices' design. Indeed, there are no studies regarding the hand and elbow discomfort threshold or sensitivity. To overcome these literature gaps, the discomfort threshold of hand and elbow were recorded at 24 spots by pushing a cylinder with a diameter of 10 mm until the participants reported not to be longer comfortable. Experiments were performed with 24 participants, 13 females and 11 males. The results showed the map of discomfort threshold (or sensitivity) for the hand and elbow. The olecranon, situated at the ulna's upper (proximal) end, one of the two bones in the forearm, could withstand more pressure than the elbow area surrounding it. The fingertips and the area close to the metacarpals were most sensitive (lower discomfort threshold).