Research attempting to elucidate physical activity (PA) intention-behavior relations has focused on differences in long-term behavior forecasting between people. However, regular PA requires a repeated performance on a daily or within-daily basis. An empirical case study application is presented using intensive longitudinal data from a study of PA in adults to (a) describe the extent to which shortterm intention-behavior coupling occurs and (b) explore time-varying predictors of intention formation and shortterm intention-behavior coupling. Adults (n = 116) participated in three 4-day waves of ecological momentary assessment (EMA). Each day, participants received EMA questionnaires assessing short-term PA intentions and wore accelerometers to assess whether they engaged in ≥10 min of moderate-to-vigorous physical activity (MVPA) in the 3-hour period after each EMA prompt. Concurrent affective states and contexts were also assessed through EMA. Participants reported having short-term intentions to engage in PA in 41% of EMA prompts. However, participants only engaged in ≥10 min of MVPA following 16% of the prompts that short-term PA intentions were reported indicating an intention-behavior gap of 84%. Odds of intentions followed by PA were greater on occasions when individuals reported higher levels of positive affect than was typical for them. This study is the first to take an EMA approach to describe short-term intentionbehavior coupling in adults. Results suggest that adults have difficulty translating intentions into behavior at the momentary level, more so than over longer timescales, and that positive affect may be a key to successfully translating intentions into behavior.
Keywords
Intention-behavior gap, Exercise, Planned behavior, MotivationIntentions to engage in physical activity (PA) are posited as a proximal determinant of behavior in many popular theories of motivation [1,2]. Yet, the predictive power of intentions to explain PA behavior is often limited in empirical studies [3,4]. Previous research has almost exclusively focused on identifying time-invariant predictors of why some people have stronger intentions than others (i.e., intention formation) or are better able to follow-though with their intentions than others (intention-behavioral coupling) [5,6]. Studies in this area often focus on long-term intentions such as intentions to engage in regular PA over time spans up to several months. As a result, it is unclear what time-varying factors predict intentions to be active and intention-behavior coupling over shorter time frames such as minutes and hours, which may be important for understanding why individuals fail to engage in PA that was intended just a few hours earlier. This article describes methods for using intensive longitudinal data (IDL) collected through ecological momentary assessment (EMA) as well as accelerometery to investigate short-term intentions to be active and intention-behavior coupling in adults.Even though individuals may form intentions to be active, evidence ...