The Influence of Friends on Physical Activity and Sedentary Behavior in Adolescents: A Mixed-Methods Analysis

PURPOSE: 1) Determine the association between adolescent moderate-to-vigorous physical activity (MVPA) and screen time with their nominated friends’ behaviors and 2) explore potential social influences of friends on MVPA and screen time METHODS: Participants consisted of 152 adolescents (mean age: 14.5 years, 53% female, 50% high school, 80% Caucasian). MVPA was measured with an Actigraph GT3X+ accelerometer. Demographic and psychological variables were assessed via questionnaires. Participants nominated up to 5 friends who completed MVPA and screen time questionnaires. A subset of adolescents (n=108) participated in focus groups that examined friends’ influence on activity behavior. Multiple regression analysis examined the association of demographic, psychological, and nominated friend variables with participants’ MVPA, sedentary behavior (SB), and screen time. NVivo 10.0 was used to analyze qualitative data. RESULTS: Greater levels of friends’ MVPA was associated with greater levels of MVPA in both middle school (p=.02) and high school females (p=.03). Greater levels of friends’ screen time was associated with greater levels of screen time in middle school males (p=.03). Focus group data indicated that friends positively influenced participants’ MVPA through engaging in activity with participants, verbal encouragement, and modeling of MVPA. All participants preferred to be active with friends rather than alone, however, females preferred activity with a close friend while males preferred to be active with a group. Enjoyment of MVPA was the most cited reason for engaging in MVPA with friends. The majority of participants reported friends not having an influence on screen time. CONCLUSIONS: Friends influence MVPA in youth, while having limited influence on SB and screen time. Interventions to increase MVPA in youth could be designed to include friends to increase enjoyment of MVPA.