Observing Others' Workouts on Social Network Sites Improves the Observer's Physical Activity: A Moderated-Mediation Model.

Many people like to share their physical activity (PA) experiences on social network sites (SNSs). Drawing on social cognitive theory, we examined in two studies whether observing others' workouts on SNSs could improve the observer's PA via the mediation of workout self-efficacy. In study 1, a two-wave longitudinal online survey of 461 participants, exposure to SNS workout posts was positively associated with PA through workout self-efficacy. In study 2, an online experimental study with 124 participants, manipulating perceived similarity revealed that it moderates between exposure to SNS workout posts and workout self-efficacy. Moreover, moderation of the indirect effect between exposure to SNS workout posts and PA via workout self-efficacy was supported. These findings reveal the mechanisms and boundary conditions of social media exposure improving workout self-efficacy and promoting PA.