Social support and physical activity participation among healthy adults: a systematic review of prospective studies

The objective of this review was to determine the direction and strength of the prospective relationship between social support and PA among healthy adults. A systematic review was conducted; including studies up until December 2015, in the following databases: Ovid MEDLINE, EMBASE, PsychINFO, SPORTDiscus, and Scopus. Published English and French written studies were included if the reported study used a longitudinal design; examined the relationship between social support and PA over at least two intervals; and assessed a sample of healthy adults between 18–65 years of age. Two reviewers independently extracted study information and independently assessed the risk of bias in each study. The initial search yielded a total of 2892 citations, and 20 studies were included in the review. Follow-up period ranged from 2 weeks to 10 years. Irrespective of the type and source of support, the strength and direction of the association between social support and PA was inconsistent across studies, with effect sizes ranging from small to large and from negative to positive. Based on meta-analysis, there was a small positive association between support for PA from friends and future PA. Researchers are encouraged to continue to conduct longitudinal studies to better understand the relationship between social support and PA.