Abstract

Background. The use of hand-held devices such as smartphone has been associated with shoulder pain and scapular muscles imbalance as a result of hyperactivity and tightness. Aim. Purpose of this study was to investigate the effect of smartphone duration use on pain of the upper back and scapular muscles strength in normal subjects, Methods. This study was cross sectional observational study; Eighty normal adults 20-30 years age, with right hand dominance were recruited for this study. The subjects must have at least 6 months experience in using smartphone and divided into two groups: Group A used smartphone less than 4 hours daily and group B used smartphone more than 4 hours daily. Subjects was assessed once time. Upper back pain was assessed by Visual Analogue Scale (VAS) scale and strength assessed by break test through pull and push dynamometer. Results. subjects in the two groups showed significant pain accentuation after smartphone usage, depends on the duration. Furthermore, changes in pain severity with smartphone use were different between the two groups (P<0.05). For scapular adductor muscles strength, the right dominant side was diminished but not reach to cause significant difference (P>0.05) and the left side have increase in strength with significant difference (P<0.05). Conclusion. Smartphone continuous use for more than 4 hours daily led to increase shoulder or parascapular pain and decrease strength of scapular adductor muscles in right dominant side due to prolonged hyperactivity, then led to weakness and increase the strength of left side due to hyperactivity of left side during holding or static postures and bilateral hand texting.