Over the past decade a rapid increase in research has taken place concerning the role of social support in youth sport. The role of parents, coaches, and peers in creating a climate that promotes and rewards effort and improvement over winning has been shown to predict continued participation in sport (Gardner, Magee, & Vella, 2017). Researchers have highlighted that youth sport participants are most likely to experience positive developmental outcomes when interactions are characterized by positive and informational feedback, appropriate role modelling, and autonomy-supportive engagement styles (Atkins, Johnson, Force, & Petrie, 2015). Moreover, studies have demonstrated how social support dynamically changes over time and has a significant influence on participation patterns in sport (Laird, Fawkner, Kelly, McNamee, & Niven, 2016; Sheridan, Coffee, & Lavallee, 2014). These findings point to a significant role that social support can play in addressing drop-out from youth sport, with rates exceeding 30% in some countries (Crane & Temple, 2015). Research is needed to test the effectiveness of social support interventions in youth sport (Balish, McLaren, Rainham, & Blanchard, h t t p s : / / j o u r n a l s. c o p m a d r i d. o rg / p i