Department of Industrial and Systems Engineering, University at Buffalo, Buffalo, NY, USA.
Department of Industrial Engineering, Clemson University, Clemson, USA.
Hum Factors. 2024 Feb;66(2):437-450. doi: 10.1177/00187208221087760. Epub 2022 Apr 27.
The present study aims to evaluate the effects of posture, task, and handgrip style on discomfort, neck kinematics, and concomitant muscular activity when using a smartphone (SP).
Along with the popularity of smartphones, musculoskeletal disorders have become prevalent among smartphone users. However, comprehensive aspects of discomfort, kinematics, and electromyographic responses across various conditions remain to be investigated.
Twenty-four young smartphone users performed typing, video watching, and reading tasks while holding the smartphone both with one hand and with two hands while either sitting or standing. Neck kinematics and muscular activities were simultaneously recorded.
Working with SPs led to higher discomfort in the neck ( = 0.01), lower back ( = 0.01), and shoulder ( = 0.04) while sitting as compared to standing. Sitting was associated with greater neck flexion and more minor lateral bending for all tasks and grip styles ( < 0.05). Electromyographic analysis indicated significant differences between sitting and standing, with alterations being dependent on the test condition. Moreover, neck kinematics and muscular activities significantly differed based on the task nature, handgrip, and interactions.
This study highlights the risk of using smartphones in increased neck angle flexion and muscular activities fatigue. Thus, posture and handgrip should be considered while using SPs. As each test condition affects a specific dependent variable, a holistic approach is required to evaluate the responses of SP users' musculoskeletal systems.
Results can be applied to develop guidelines for musculoskeletal disorders/discomfort prevention among SP users, especially with the rise of smartphone use during the COVID-19 pandemic.
本研究旨在评估姿势、任务和握持方式对使用智能手机（SP）时的不适感、颈部运动学和伴随肌肉活动的影响。
随着智能手机的普及，肌肉骨骼疾病在智能手机用户中变得普遍。然而，各种条件下的不适感、运动学和肌电图反应的综合方面仍有待研究。
24 名年轻的智能手机用户在坐姿和站姿时分别单手和双手握持 SP 进行打字、观看视频和阅读任务，同时记录颈部运动学和肌肉活动。
与站立相比，坐姿时使用 SP 会导致颈部（ = 0.01）、下背部（ = 0.01）和肩部（ = 0.04）的不适感更高。对于所有任务和握持方式，坐姿时颈部的前屈和侧向弯曲度更小（ < 0.05）。肌电图分析表明，坐姿和站姿之间存在显著差异，变化取决于测试条件。此外，颈部运动学和肌肉活动根据任务性质、握持方式和相互作用而显著不同。
本研究强调了使用智能手机时增加颈部角度前屈和肌肉活动疲劳的风险。因此，在使用 SP 时应考虑姿势和握持方式。由于每种测试条件都会影响特定的因变量，因此需要采用整体方法来评估 SP 用户肌肉骨骼系统的反应。
结果可用于为智能手机用户制定肌肉骨骼疾病/不适预防指南，尤其是在 COVID-19 大流行期间智能手机使用增加的情况下。
