Effect of the presence or absence of upper limb support on posture when a smartphone user is in a seated position under ambient light conditions

Abstract

BackgroundHome, public transport, work, the number of environmental positions constraining the use of smartphones is significant. Research questionHow can the presence of an upper limb support influence the sitting posture of smartphone users under fixed illumination and brightness? MethodsTwelve subjects (21,6 ± 5,5 years old) performed web browsing under two environmental positions (POSITION): sitting with and without support (table). The users' postures were evaluated through relative kinematics joint angles analysis. A repeated measure analysis of variance and Tukey post-hoc tests were performed to test the effect of POSITION on posture. ResultsIn sitting position in front of a table, neck is less stressed (flexion < 10°) and trunk and shoulder are supported which suggests less constrains for the joints. Relevance to industryTo prevent injury or pain, the use of an upper limb support (to lean on) should be considered for people/workers who use the smartphone frequently.