The Effect of Break on Discomfort and Variation in EMG Activities While Using a Smartphone: A Preliminary Study in a Chinese University Population

(1) Background: Despite the substantial increase in the number of adolescent smartphone users, few studies have investigated the behavioral effects of smartphone use on adolescent students as it relates to musculoskeletal discomfort; (2) Methods: The aim of our study was to estimate the prevalence of musculoskeletal symptoms in university students and determine the relationship between smartphone use and musculoskeletal symptoms among this population through an online survey. Considering the dynamic and cumulative characteristics of muscle activities, the most common body parts reported discomfort in the survey were selected to gauging muscle activities during smartphone use by collecting surface EMG signals. Then, according to the changing of muscle activities, a comparison experiment was conducted to give an intervention to eliminate the probability of occurrence of muscle discomfort; (3) Results: Neck/shoulder, arms, upper back, wrist/hand, and low back were the most commonly reported muscle locations with discomfort/pain; in the EMG experiment, a 10-min rest after 30-min smartphone usage was effective to keep the EMG activity at a relatively stable state; (4) Conclusions: This study offers the possibility of being applied to smartphone users and provides preliminary data support and theoretical exploration for follow-up early muscle fatigue detection system.