Extending the Theory of Planned Behavior: The Role of Self and Social Influences in Predicting Adolescent Regular Moderate-to-Vigorous Physical Activity

Abstract

The current study aimed to test the validity of an extended theory of planned behavior model (TPB; Ajzen, 1991), incorporating additional self and social influences, for predicting adolescent moderate-to-vigorous physical activity. Participants (N = 423) completed an initial questionnaire that assessed the standard TPB constructs of attitude, subjective norm, and perceived behavioral control, as well as past behavior, self-identity, and the additional social influence variables of group norms, family social support, friends' social support, and social provisions. One week after completion of the main questionnaire, participants completed a follow-up questionnaire that assessed self-reported physical activity during the previous week. The standard TPB variable--past behavior, self-identity, and group norms, but not social support influences--predicted intentions, with intention, past behavior, and self-identity predicting behavior. Overall, the results provide support for an extended version of the TPB incorporating self-identity and those social influences linked explicitly to membership of a behaviorally relevant reference group.

Social Influences and the Physical Activity Intentions of Parents of Young-Children Families

“…The lack of examination of a range of other social influences (e.g., social pressures and normative behaviors) alongside social support (see Hamilton & White, 2008) might account for the discrepancy in findings as might the way in which specific cohorts of the population perceive social support as influencing their PA performance. For example, social support is found to be more influential for females' rather than for males' PA-related behavior (Leslie et al, 1999;Phongsavan, McLean, & Bauman, 2007).…”

“…While the importance of social support for PA performance has been widely accepted, investigations of social support within the TPB framework have resulted in equivocal findings in which some studies have found social support to add predictive value to intentions (Courneya et al, 2000) whereas others have found no such effect (Hamilton & White, 2008).…”

“…Thus, when an individual identifies strongly as a person who performs a particular behavior, the behavior then becomes an important part of their selfconcept, in turn, influencing their motivation to engage in the behavior. Support for the inclusion for self-identity within the TPB was demonstrated in a metaanalysis that found self-identity to account for an additional 1% of the variance in behavioral intentions over and above the TPB constructs (Conner & Armitage, 1998), with a significant effect for self-identity found in the context of PA (Hamilton & White, 2008;Jackson, Smith, & Conner, 2003). More specifically, qualitative research examining the influence of social roles on parental PA suggests that, through the experience of parenthood, the meanings of PA is altered and that having an active role identity is viewed within the framework of parenting not within the framework of the individual (Hamilton & White, 2010a).…”

Assessing Intentions to Eat a Healthful Diet Among National Collegiate Athletic Association Division II Collegiate Athletes

“…Few researchers have assessed sex differences using the TPB to predict diet-related behaviors of adolescents and young adults. Hamilton and White 18 observed TPB constructs for physical activity among adolescents. Although they stated previous investigators had demonstrated that social support may be more influential for females, they found no differences between sexes for social norms.…”

“…Our goal was to expand on those data to include many sports and both sexes. Additionally, we were not aware of any authors who had looked at sex differences and the TPB among collegiate athletes, and only a few investigators 18,19 had researched a similar age group with equivocal results.…”