Abstract
BACKGROUND: Prolonged use of electronic devices in virtual classrooms can influence posture, neck angle, and body discomfort. Recent evidence suggests that not only "incorrect" postures but also sustained static positions, regardless of being ergonomically correct, contribute to musculoskeletal strain. However, limited studies have directly compared posture and discomfort across different types of devices in a virtual classroom setting. OBJECTIVE: To evaluate differences in posture, neck angle, and body discomfort among female university students during the use of three electronic devices (smartphone, tablet, notebook) in a virtual classroom for 20 min. METHODS: Twenty-four healthy female participants (aged 18-23 years) completed three randomized sessions using a smartphone, tablet, or notebook in a virtual classroom task. Posture was assessed using the Rapid Upper Limb Assessment (RULA), neck angle was measured via motion analysis, and body discomfort was rated with a standardized visual analog scale. Statistical analyses were performed using repeated-measures ANOVA with Bonferroni correction, with effect sizes reported. RESULTS: Significant differences were observed in posture (RULA scores: smartphone 5.12 ± 1.26; tablet 4.62 ± 1.35; notebook 4.21 ± 1.32, p < 0.05), neck angle (smartphone 32.48 ± 11.81 and tablet 36.93 ± 7.97, p > 0.05; notebook 39.30 ± 7.82, p > 0.05), and body discomfort of all regions (VAS: smartphone 1.08 ± 1.69; tablet 1.06 ± 1.75; notebook 1.01 ± 1.66, p < 0.05). Although all devices induced discomfort after 20 min of sustained posture, the smartphone condition showed the greatest neck flexion and discomfort. CONCLUSION: This study demonstrates that sustained posture during virtual classroom activities leads to increased neck angle deviation and body discomfort, with device type influencing the magnitude of these effects. These findings highlight the importance of postural variability and active breaks, rather than relying solely on maintaining a "correct" posture, to reduce musculoskeletal strain in technology-based learning environments.