Literature review on seat comfort during smartphone use in public transport systems

Smartphone use in public transport systems increased from 8% to 48% from the years 2014 to 2018. Smartphones are often used while the users are seated. However, seats are often not designed for this activity. Smartphone use while seated could cause discomfort, especially in the upper limbs, back and neck, and could lead to musculoskeletal disorders (MSDs). This systematic review summarizes smartphone use with attention to the activities done, durations, postures, characteristics of the human body, discomfort experience and needs of the users, with special attention for vehicle seats. In addition, potential improvements of the seat are reviewed. In all, 185 articles were collected from the Scopus and Pub-Med databases. The abstracts were screened by two researchers and then compared and discussed based on a set of inclusion criteria. Forty-five publications met the criteria, and five were added because the authors were familiar with them. The literature shows that the smartphone is often used with two hands, sometimes with the elbows on an armrest. Smartphone use influences discomfort, which mainly occurs in the neck and back. To improve the neck and back positions, the armrest should be at the correct height. Using a smartphone with proper arm support might prevent neck and back pain. The number of studies on smartphone use while travelling is limited. Most studies are conducted in the laboratory, at home or the office. Many papers state that neck bending should be prevented, and smartphone usage time should be limited. Some studies mention that the preferred angle of the backrest for smartphone use is 120 degrees in an aircraft seat and an arm support should be added. Further research is needed on this point, especially for other vehicles. In future studies, redesigned seats should be tested by smartphone users. The redesign can be based on the first design directions presented in this paper.

2014年至2018年间，公共交通场景中的智能手机使用率从8%升至48%。使用者通常在就座时操作智能手机，但现有座椅往往未针对该使用场景进行优化设计。就座状态下使用智能手机可能引发身体不适，尤其累及上肢、背部与颈部，甚至可能导致肌肉骨骼疾患（musculoskeletal disorders, MSDs）。本系统综述聚焦于智能手机使用的相关活动、使用时长、操作姿势、人体特征、不适体验与用户需求，重点关注车辆座椅相关场景；同时综述了座椅的潜在优化方案。研究团队从Scopus与PubMed数据库中共检索到185篇文献，由两名研究人员对文献摘要进行初筛，随后依据一套纳入标准开展比对与讨论。最终有45篇文献符合纳入标准，另因研究团队熟悉相关领域，补充纳入5篇文献。现有研究表明，人们通常以双手操作智能手机，有时会将肘部倚靠在扶手之上。使用智能手机会加重身体不适症状，不适主要集中于颈部与背部。为改善颈部与背部姿态，扶手应设置于合适高度。借助恰当的手臂支撑使用智能手机，或可预防颈背疼痛。目前针对出行途中使用智能手机的研究数量有限，多数研究开展于实验室、家庭或办公场景。多篇文献指出，应避免颈部过度弯曲，并限制智能手机的连续使用时长。部分研究提出，在飞机座椅上，适配智能手机使用的靠背最优倾角为120度，且应增设手臂支撑装置。该领域仍需开展更多相关研究，尤其是针对其他交通工具的场景。未来的研究可邀请智能手机用户对重新设计的座椅进行实测验证，而座椅的重新设计可参考本文提出的初步设计方向。