LAUSR

Real-time measurement of the craniovertebral, thoracic kyphosis and lumbar lordosis angles during natural and smartphone usage postures in sitting were analyzed in a cohort of 560 adolescents using independent t-tests and Spearman's correlations between their reported musculoskeletal symptoms, daily device use and school year. Students with musculoskeletal symptoms (mean difference: 4.1° - 9.4°, p < .001) and in secondary schools (mean difference: 13.6° - 29.4°, p < .001) had a greater forward-head posture quantified by craniovertebral angle in both postures. Loss of lumbar lordosis was found in students spending ≥ 2 hours/day on electronic devices (mean difference: 3.2°, p = .029) and those with musculoskeletal symptoms (mean difference: 5.4°, p = .001). Secondary school students exhibited a greater thoracic kyphosis when using smartphones (mean difference: 3.3°, p = .003). Findings suggest urgent needs of early and proactive intervention targeted to minimize the risk of developing musculoskeletal disorders related to intense device use for young adolescents.