THE IMPACT OF SCREEN TIME, POSTURAL BEHAVIOR, AND PHYSICAL ACTIVITY ON THE MUSCULOSKELETAL SYSTEM OF HIGH SCHOOL STUDENTS

Abstract

The prevalence of musculoskeletal disorders among adolescents reaches 45-70%, with mobile device use in non-physiological postures considered a key modifiable risk factor. However, for the North Caucasus population, systematic studies linking behavioral patterns with objective orthopedic examination data are lacking. The aim of this study was to assess the prevalence of musculoskeletal disorders among high school students in Makhachkala and to identify behavioral risk factors associated with gadget use, learning posture, and physical activity. A cross-sectional study involving 840 adolescents aged 15-18 years undergoing routine preventive examination was conducted. All participants completed an anonymous questionnaire assessing screen time, predominant learning posture, and regularity of sports activities. Orthopedic examination included visual posture assessment, scoliometry, and forward head posture registration. Statistical analysis was performed using binary logistic regression with adjusted odds ratios. Musculoskeletal disorders were identified in 468 adolescents (55.7%). The strongest risk factor was studying in a lying position (aOR=4.92; 95% CI: 3.15-7.69), whereas regular sports activities acted as a protective factor (aOR=0.31; 95% CI: 0.22-0.44). High screen time (>6 h/day) increased the risk 2.68-fold compared with low screen time (<4 h/day); each additional hour increased the risk by 29%. The combination of sports absence and lying posture produced a synergistic effect: the risk rose to 7.84 (95% CI: 4.79-12.84), with musculoskeletal disorders in this subgroup reaching 80.3%. These findings substantiate the need for comprehensive preventive programs including postural behavior correction, screen time limitation, and mandatory promotion of regular physical activity.