Department of Industrial Engineering and Management, Ming Chi University of Technology, 84 Gung-Juan Road, Taishan, New Taipei, 243303, Taiwan.
Formosa Plastics Group, Taipei, 114030, Taiwan.
Sci Rep. 2024 Jun 6;14(1):12994. doi: 10.1038/s41598-024-63734-0.
Women frequently express heightened neck discomfort even though they exhibit smaller neck flexion (NF) during smartphone use. Differences in natural posture while using smartphones may result in varying muscle activation patterns between genders. However, no study focused on this issue. This study investigated the influence of gender on neck muscle activity and NF when using smartphones, ranging from slight (20°) to nearly maximal forward head flexion, across different postures. We analyzed smartphone usage patterns in 16 men and 16 women and examined these behaviors across different scenarios: standing, supported sitting, and unsupported sitting, at 20°, 30°, 40°, and the maximum head angles. During data collection, muscle activity was measured, expressed as a percentage of the maximum voluntary contraction (%MVC), in the cervical erector spinae (CES) and upper trapezius (UTZ), along with NF. Results show significant influences of gender, head angle, and posture on all measures, with notable interactions among these variables. Women displayed higher muscle activities in CES and UTZ, yet exhibited lesser NF, while using smartphones in both standing (12.3%MVC, 10.7% MVC, and 69.0°, respectively) and unsupported sitting (10.8%MVC, 12.3%MVC, and 71.8°, respectively) compared to men (standing: 9.5%MVC, 8.8%MVC, and 76.1°; unsupported sitting: 9.7%MVC, 10.8%MVC, and 76.1°). This study provides a potential rationale for gender-related disparities in injury outcomes, emphasizing that women experience higher neck and shoulder discomfort level, despite their smaller NF during smartphone use, as found in previous research. Additionally, the cervical flexion-relaxation phenomenon may occur when the head angle exceeded 40°. The near-maximum head angle during smartphone use might induce the cervical flexion-relaxation phenomenon, potentially aggravating neck issues. We recommend limiting smartphone usage postures that exceed the near-maximum head angle, as they are commonly adopted by individuals in the daily smartphone activities.
女性在使用智能手机时经常会感到颈部不适，尽管她们的颈椎前屈度（NF）较小。使用智能手机时的自然姿势差异可能导致男女之间的肌肉激活模式不同。然而，目前还没有专门针对这一问题的研究。本研究旨在探讨性别对使用智能手机时颈部肌肉活动和 NF 的影响，涵盖从轻度（20°）到接近最大前屈角度的范围，同时考虑不同的姿势。我们分析了 16 名男性和 16 名女性使用智能手机的模式，并在不同场景下（站立、有支撑的坐姿和无支撑的坐姿），在 20°、30°、40°和最大头部角度下，检查了这些行为。在数据采集过程中，测量了颈椎伸肌（CES）和上斜方肌（UTZ）的肌肉活动，并用 NF 表示，结果以最大自主收缩的百分比（% MVC）表示。结果表明，性别、头部角度和姿势对所有测量值都有显著影响，这些变量之间存在显著的相互作用。与男性相比，女性在站立和无支撑坐姿时使用智能手机时，CES 和 UTZ 的肌肉活动更高，但 NF 更小（站立：12.3%MVC、10.7%MVC 和 69.0°；无支撑坐姿：10.8%MVC、12.3%MVC 和 71.8°）。与男性相比，女性在站立和无支撑坐姿时使用智能手机时，CES 和 UTZ 的肌肉活动更高，但 NF 更小（站立：9.5%MVC、8.8%MVC 和 76.1°；无支撑坐姿：9.7%MVC、10.8%MVC 和 76.1°）。本研究为与性别相关的损伤结果差异提供了潜在的理论依据，强调了尽管女性在使用智能手机时 NF 较小，但她们的颈部和肩部不适程度更高，这与之前的研究结果一致。此外，当头部角度超过 40°时，可能会出现颈椎前屈-放松现象。在使用智能手机时接近最大的头部角度可能会引起颈椎前屈-放松现象，从而加重颈部问题。我们建议限制使用超过接近最大头部角度的智能手机姿势，因为这些姿势在日常生活中经常被智能手机使用者采用。
