Neck and shoulder strains under various head flexing positions while standing and sitting with and without back support for male and female smartphone users

Chen, Yi-Lang; Chan, You-Chun

doi:10.1080/00140139.2023.2270651

Cited by 4 publications

(1 citation statement)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, a research gap exists in terms of assessing the ergonomic implications of visual strain during smartphone usage. While previous studies have incorporated GA and VD alongside NF and HF angles [19][20][21], a comprehensive investigation into the visual strain associated with smartphone use across different usage scenarios is still lacking.…”

Section: Introductionmentioning

confidence: 99%

User Walking Speed and Standing Posture Influence Head/Neck Flexion and Viewing Behavior While Using a Smartphone

Chen,

Nguyen

2023

Healthcare

Self Cite

View full text Add to dashboard Cite

The habit of using smartphones while walking has become widespread among modern individuals, particularly when pedestrians are in a hurry. However, there has been little exploration into the differences between standing and walking at various speeds in terms of smartphone use. In this study, we examined 60 young participants (30 men and 30 women) who engaged in smartphone tasks such as one-handed browsing or two-handed texting while standing, walking slowly, and walking normally. The measured variables included neck flexion (NF), head flexion (HF), gaze angle (GA), and viewing distance (VD). The study findings indicate that using smartphones while walking may cause a more pronounced kyphotic curve in the cervical spine compared to when standing, leading to increased strain in the neck region. The heightened neck load can be attributed to the concurrent dynamic nature of both walking and smartphone usage. Moreover, two-handed texting had a more detrimental impact on NF, HF, and GA when contrasted with one-handed browsing. The interplay among hand operation, posture, and maintaining arm position displayed an uncertain correlation with VD. While women typically exhibited smaller NF, HF, and GA than men, it is important to explore whether their shorter VD might contribute to increased eyestrain.

show abstract

Section: Introductionmentioning

confidence: 99%

User Walking Speed and Standing Posture Influence Head/Neck Flexion and Viewing Behavior While Using a Smartphone

Chen,

Nguyen

2023

Healthcare

Self Cite

View full text Add to dashboard Cite

show abstract

Gender differences in neck muscle activity during near-maximum forward head flexion while using smartphones with varied postures

Chen,

Chan,

Alexander

2024

Sci Rep

View full text Add to dashboard Cite

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.

show abstract

Eyestrains among smartphone users while watching videos in Taipei MRT carriages: a comparison between sitting and standing postures

Chen,

Chu,

Huang

et al. 2024

Sci Rep

View full text Add to dashboard Cite

In MRT carriages, more passengers are watching videos on their smartphones during daily commutes, yet the impact of these viewing conditions on visual strain remains unexplored. This study examined eyestrain in 24 male and 24 female participants while watching videos on smartphones in two postures (sitting and standing) and over two durations (15 min and 30 min) in Taipei MRT carriages. We measured critical flicker fusion frequency (CFF) reduction, visual fatigue scale (VFS) scores, and viewing distance (VD) for each trial. Results revealed significant effects of sex, posture, and viewing duration on visual strain, with notable two-way interactions (sex × posture and posture × time) influencing most outcomes. Women showed greater CFF reduction while sitting compared to standing (3.47 Hz vs. 1.90 Hz, p < 0.001) and maintained shorter VDs while seated (25.5 cm vs. 34.3 cm, p < 0.001). However, they reported higher VFS scores when standing (8.94 vs. 4.60, p < 0.001), indicating increased discomfort while standing in the moving MRT carriage. Men exhibited higher CFF reduction (2.81 Hz) than women while standing (1.90 Hz) (p < 0.01), but this difference was not observed while sitting. Eyestrain indicators significantly worsened after 30 min of viewing compared to 15 min, with stronger effects on VFS scores and VDs. This finding supports the recommendation to take breaks after 20 min of smartphone use, even in MRT carriages. Although subjective eyestrain is not always recognized, watching videos on smartphones while seated can result in unexpectedly high levels of objective visual fatigue, indicated by CFF reduction. Our findings suggest that eyestrain patterns in MRT carriages differ from those reported in previous studies. Seated passengers, particularly females with shorter VD, may experience unrecognized eyestrain that could impact eye health, while standing passengers may face greater discomfort. These results highlight the need for increased awareness and preventive measures to mitigate eyestrain in digital public transportation environments.

show abstract

Neck and shoulder strains under various head flexing positions while standing and sitting with and without back support for male and female smartphone users

Cited by 4 publications

References 51 publications

User Walking Speed and Standing Posture Influence Head/Neck Flexion and Viewing Behavior While Using a Smartphone

User Walking Speed and Standing Posture Influence Head/Neck Flexion and Viewing Behavior While Using a Smartphone

Gender differences in neck muscle activity during near-maximum forward head flexion while using smartphones with varied postures

Eyestrains among smartphone users while watching videos in Taipei MRT carriages: a comparison between sitting and standing postures

Contact Info

Product

Resources

About