The effect of laying down posture while using smartphone among school children in Nakhon Si Thammarat, Thailand

Background: Lots of children use the smartphone in lying down posture that is unappreciated posture. The postures of children while using a smartphone affect their musculoskeletal pain and can enhance Musculoskeletal Disorders (MSDs). Objective: To study the effect of lying down posture while using smartphone among school children in Nakhon Si Thammarat, Thailand. Materials and methods: This survey study employed a Descriptive Cross-Sectional Design. The population was Grade 1-6 students studying in a primary school in Nakhon Si Thammarat. There were 122 samples selected based on the Volunteer Sampling Technique under the written consent of the students' guardians. The research instruments employed in this study were: 1) Questionnaire adapted from Nordic Musculoskeletal Questionnaire asking musculoskeletal symptoms, 2) Posture Assessment using Kinovea Software to measure the angles of the muscle and postures during photo and video shooting of the smartphone users. The data were analyzed using descriptive statistics while Chi-square and Mann-Whitney U tests were used to test the mean differences. Results: There is a significant difference at p<0.05 level in mean angles of the neck, trunk, shoulder, and lower arms when using smartphones in supine and prone postures. The correlation between smartphone usage postures and musculoskeletal symptoms at the head/neck, trunk, and upper arm are found significantly different at p<0.05 level. The statistically significant difference at p