Effect of daytime on smartphone use posture and related musculoskeletal disorders risk among university students during the weekend.

Time spend using smartphones is constantly increasing. Portability leads to postures that expose them to musculoskeletal disorders (MSDs). The aim was to study the effect of time of day (morning, afternoon, evening and night) on university students' postures when using their smartphones over the weekend and their link with MSD risk. A cross-sectional survey was conducted among 277 university students (25.3% female, 74.7% male, 17-24 years). SmarTaxo with 41 postures (sitting, standing, lying, walking) and their relative RULA (Rapid Upper Limb Assessment) scores were considered. The overall distribution of postures was: 36.22% sitting, 17.53% standing, 37.67% lying down and 8.57% walking. Six lying and one standing posture observed in the evening and at night are at high MSD risk (RULA score = 6, 23% of total time). The survey highlighted that university students are exposed to MSDs during the weekend day due to awkward postures, especially when lying down at night.