PDF(Pubmed)
Abstract：
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.
摘要：
女性经常表现出更高的颈部不适，即使她们在智能手机使用期间表现出较小的颈部屈曲（NF）。使用智能手机时自然姿势的差异可能会导致性别之间肌肉激活模式的变化。然而,没有研究集中在这个问题上。这项研究调查了使用智能手机时性别对颈部肌肉活动和NF的影响，范围从轻微（20°）到接近最大的前屈头，跨越不同的姿势。我们分析了16名男性和16名女性的智能手机使用模式，并在不同的场景中检查了这些行为：站立，支持坐,没有支撑的坐着，20°,30°,40°,和最大头部角度。在数据收集过程中,测量肌肉活动，表示为最大自愿收缩的百分比(%MVC)，在颈竖脊肌（CES）和上斜方肌（UTZ）中，随着NF。结果显示性别的显著影响，头部角度,和所有措施的姿势，这些变量之间存在显著的相互作用。女性在CES和UTZ中表现出更高的肌肉活动，但表现出较低的NF，同时使用智能手机(12.3%MVC，10.7%MVC，69.0°，分别)和不支持的坐姿(10.8%MVC，12.3%MVC，和71.8°，分别）与男性相比（站立：MVC9.5%，8.8%MVC，和76.1°；不支持坐姿：9.7%MVC，10.8%MVC，和76.1°）。这项研究为伤害结果中与性别相关的差异提供了潜在的理由。强调女性经历更高的颈部和肩部不适水平，尽管在智能手机使用过程中NF较小，正如在以前的研究中发现的那样。此外,当头部角度超过40°时，可能会出现颈椎屈曲松弛现象。智能手机使用过程中头部角度接近最大可能会导致颈椎屈曲放松现象，可能会加剧颈部问题。我们建议限制超过接近最大头部角度的智能手机使用姿势，因为它们通常被个人在日常智能手机活动中采用。
