Analysis of Reddit Discussions on Motivational Factors for Physical Activity: Cross-Sectional Study

Background: Despite the ample benefits of physical activity (PA), many individuals do not meet the minimum PA recommended by health organizations. Structured questionnaires and interviews are commonly used to study why individuals perform PA and their strategies to adhere to PA. However, certain biases are inherent to these tools that limit what can be concluded from their results. Collecting data from social media channels can complement these studies and provide a more comprehensive overview of PA motives and adherence strategies. Objective: This study aims to investigate motives for engaging in PA, as well as the associated strategies to achieve these goals, as stated by a large number of people on a social media site. Methods: We searched for users’ responses regarding PA motives and adherence strategies in Reddit forums dedicated to PA and analyzed the data using (1) unsupervised clustering to identify topics from the textual comments and (2) supervised classification to classify the comments into the detected topics. A panel of experts participated in both steps for annotation and validation purposes. Results: We analyzed 1577 unique user comments (representing 1577 individual users); of those, 1247 were linked to physical appearance (mentioned in 298/1247, 23.9% of the comments) and improving physical (235/1247, 18.9%) and mental health (211/1247, 16.9%), indicating these as the main motivational factors. The main strategies people used to adhere to PA were habit formation (373/1247, 30%), goal setting (173/1247, 13.9%), enjoyable activities (151/1247, 12.1%), socializing (121/1247, 9.7%), using media (111/1247, 8.9%), using different apps to monitor PA (35/1247, 2.8%), and financial commitment (32/1247, 2.5%). Conclusions: This study presented a novel approach using a language model to investigate why people engage in PA and the strategies they use to adhere to PA using wide-scale, self-disclosed content from popular social media channels.