Write a 5-page reflection on the following links provided below. Follow the essay structure guide for the structure of the essay. Unit 6 https://csepguidelines.ca/ https://health.gov/sites/default/

Methods: 4,073 adolescents completed a self-administered web-based survey related to physical activity (PA).

Results: TPB explained 59% and 43% of the variance for intention and behavior, respectively. Moderating (by gender) and mediating tests were supported.

Conclusions: TPB is useful for understanding PA in this population.

2011 Society for Adolescent Health and Medicine. All rights reserved. The Theory of Planned Behavior (TPB) [1]is a major social- cognitive theory that has been applied to explain physical activity (PA) behavior in numerous populations. Briefly, the TPB proposes that a person’s intention to perform a behavior is the central deter- minant of that behavior because it reflects the level of motivation a person is willing to exert to perform the behavior [1]. Intention is hypothesized to be determined by attitude, subjective norm, and perceived behavioral control. Attitude is reflected in a positive or negative evaluation of performing the behavior. Subjective norm is defined as the perceived social pressure to perform the behavior, whereas perceived behavioral control is defined as the perceived ease or difficulty of performing the behavior. Perceived behavioral control is also hypothesized to directly predict behavior. However, the core tenets of the TPB have not been thoroughly tested for PA in adolescent populations. The primary objective of this study was to examine the explanatory power of the TPB to explain PA behavior in a large population sample of adolescents. Secondary objectives were (i) to examine the moderating effects of gender on the TPB, and (ii) to test the mediating effects of intention on the relationship between attitude, subjective norm, and perceived behavioral con- trol with behavior.

Methods The Web-Survey of Physical Activity and Nutrition was self- administered to students in grades 7–10, across the province of Alberta, Canada. Of the 59 school boards in the province, 85% agreed to have schools participate. Of 271 schools contacted, 109 schools across 37 school boards participated, reflecting a school board and school response rates of 64% and 40%, respectively. Overall, 4,073 of a potential 9,071 adolescents consented and completed the survey, yielding a student response rate of 44.9%. Ethics approval was ob- tained from the University of Alberta.

Measures Validated, short measures (5-point response options) of core TPB constructs (the measures of attitude, subjective norm, and intention were modified from Hagger et al [2]) were used to * Address correspondence to: Ronald C. Plotnikoff, Ph.D., School of Education, Faculty of Education and Arts, University of Newcastle, University Drive, Cal- laghan, NSW 2308, Australia. E-mail address: [email protected] (R.C. Plotnikoff). Journal of Adolescent Health 49 (2011) 547–549 www.jahonline.org 1054-139X/$ - see front matter 2011 Society for Adolescent Health and Medicine. All rights reserved.

doi:10.1016/j.jadohealth.2011.03.006 minimize response burden. A two-item construct was used to assessattitude on the basis of enjoyment and PA importance [2].

A single-item assessed subjective norm[2]which asked: “Most people important to me think I should take part in regular PA.” As a proxy to perceived behavioral control, a 4-item self-efficacy measure ( .83) [3]assessed confidence in participating in PA under various circumstances (e.g., when tired, having home- work). A single-item construct was used to assess intention, for instance, “I plan to be physically active on a regular basis over the next month.” The validated Physical Activity Questionnaire for Older Children [4]was used to assess PA levels of the participants during the previous 7-day period.

Model testing (primary objective) Structural equation models were examined using analysis of moment structures (AMOS) 17.0. To correct for the cluster- ing of effects at the school level, all variables were adjusted for school, using multiple linear regression, and the unstandard- ized residuals were used in the analyses. The proposed model was tested using maximum likelihood analysis in AMOS and the Physical Activity Questionnaire for Older Children score was used as the dependent variable.

Moderation and mediation analyses (secondary objective) Gender was identified as a potential moderator of the TPB model. Multigroup moderation analyses were conducted using a series of models, starting from unrestricted to fully constrained [5].A comparative fit index (CFI) .01 indicates that the null hypothesis of invariance should not be rejected [6]for testing multigroup invariance. Intention is thought to mediate the relationship between attitude, subjective norm, perceived behavioral control, and the behavior itself. The indirect effects of attitude, subjective norm, and perceived behavioral control were examined using single and multiple mediator models and asymmetric confidence inter- vals tested the significance of the indirect effects [7]. The product of the standardized coefficients was calculated to provide an estimate of effect size and interpreted as small (d .2), medium (d .5), and large (d .8) [8]. Results Overview The sample reflects the age/sex distribution for Alberta youth.

The mean age of our sample was 13.6 ( 1.4) versus 13.3 ( 1.3) years in the total population of Alberta of students in grades 7–10 (N 130,000). The proportion of boys in our sample was 46% versus 51% (grades 7–10) for the province. The sample (N 4,073) included 1,785 boys and 2,270 girls (18 students did not provide gender).

Model testing Although the 2statistic was significant ( 2 364.57, df 22, p .001), the TPB model represented an excellent fit to the data based on varying indices (goodness of fit [GFI] .98, adjusted goodness of fit [AGFI] .96, CFI .98, root mean square error of approximation [RMSEA] .06). All the pathways were signifi- cant (p .001) and the model explained 59% and 43%, respec- tively, of the variance for intention and behavior (Figure 1).

Moderation analyses The model was tested separately for boys and girls. In both groups, the model was found to be an excellent fit to the data (boys: 2 121.12, df 22, p .001, GFI .99, AGFI .97, CFI .99, RMSEA .05; girls: 2 214.88, df 22, p .001, GFI .98, AGFI .96, CFI .98, RMSEA .06). Model 1 (unrestricted model) was not significantly different from model 2 (measurement of equivalent model which includes equal factor loading across sub-samples). Model 3 (model constraints plus equal factor variance and covariances) was significantly different ( CFI .08) from model 2, suggesting that the relationship between constructs was stronger among boys. Similarly, model 4 (included model 3 constraints plus equal paths) was significantly different ( CFI .03) from model 3, indicating stronger path coefficients for boys. Model 5 (fully constrained model with the model 4 constraints plus equal factor residuals) was also significantly different from model 4 ( CFI .10). Table 1 Path coefficients, significance levels, and significance of the indirect effects of attitude, subjective norm, and perceived behavioral control Variables Unstandardized regression coefficients and confidence intervals Significance of indirect effectEffect size a d (SE) 95% CI (SE)95% CI 95% CI b Single mediator models c Attitude .73 (.01)* .70–.75 .23 (.01)* .21–.26 .17 .15–.18.20 Subjective norm .34 (.01)* .32–.37 .33 (.01)* .31–35 .11 .10–.12.18 Perceived behavioral control .56 (.01)* .54–.59 .16 (.01)* .14–19 .09 .08–.10.12 Multiple mediator models d Attitude .78 (.05)** .70–.88 .08 (.01)** .06–.11 .06 .05–.08.07 Subjective norm .05 (.02)** .02–.08 .08 (.01)** .06–.11 .004 .001–.007 .01 Perceived behavioral control .18 (.03)** .12–.24 .08 (.01)** .06–.11 .01 .01–.02.02 estimate of unstandardized regression coefficient of attitude, subjective norm and perceived behavioral control predicting intention; estimate of the unstandardized regression coefficient of intention predicting physical activity with attitude, subjective norm or perceived behavioral control in the model; SE standard error; 95% CI 95% confidence interval; product of coefficients estimate.

* p .001, **p .01. aEffect sizes calculated using the product of the standardized coefficients.b95% asymmetric confidence intervals of the mediated effect calculated using the Product Confidence Limits for the Indirect Effect program.cSingle mediator models tested using Statistical Package for the Social Sciences and ordinary least squares regression.dMultiple mediator models tested in the full model using Analysis of Moment Structures output. R.C. Plotnikoff et al. / Journal of Adolescent Health 49 (2011) 547–549 548 Mediation analysesThe indirect effects of attitude, subjective norm, and per- ceived behavioral control are reported in Table 1. Intention to be active was found to mediate the relationship between these variables and PA in both single and multiple mediator models.

All the hypothesized mediation pathways were statistically significant, supporting the role of intention to be physically active as a mediator of the relationship between attitude, subjective norm, perceived behavioral control, and PA behav- ior. The largest effects were found when intention was tested as a mediator of the relationship between attitude and behav- ior ( .20 in the single mediator model and .07 in the multiple mediator model).

Discussion This research appears to be the largest TPB study on youth conducted with a representative sample. Overall, our results support the TPB with statistically significant values for all con- struct pathways. Perceived behavioral control and intention ac- counted for 43% of the variance in behavior for the overall sam- ple. Attitude, subjective norm, and perceived behavioral control explained 59% of the variance for intention. These results are generally consistent with PA-TPB literature in both adolescent and adult populations [9,10].

Differences existed in the strength of associations between TPB constructs when comparing the gender-specific models.

However, for both genders, perceived behavioral control was the strongest correlate of behavior, and attitude was the stron- gest correlate of intention. This highlights the importance of practitioners/teachers to provide enjoyable activities and strategies to enhance adolescents’ confidence to adopt and sustain regular PA. Finally, the assumptions for mediation were satisfied for all three TPB constructs (i.e., attitude, subjective norm, perceived behavioral control). Although the sizes of the mediated effects were small, they did have important implications at the popula- tion level.

Acknowledgments R.C.P. and L.T. conceived the study. R.C.P. was responsible for producing the first draft of the entire manuscript. D.R.L. analyzed the data and wrote the results section. S.A.C. and L.T. assisted in writing the manuscript. S.D. was responsible for conducting the study. J.C.S., L.M., and S.D. provided comments on manuscript drafts. L.M., R.C.P., and J.C.S. were the co-investigators on the related grant, funded by the Alberta Heritage Foundation for Medical Research. All authors reviewed the final version of the manuscript.

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[10] Symonds-Downs D, Hausenblas H. The theories of reasoned action and planned behavior applied to exercise: A meta-analytic update. J Phys Act Health 2005;2:76 –97. Figure 1. Standardized parameter estimates for pathways among constructs from the Theory of Planned Behavior in adolescents. Note. All pathways statistically significant p .001. Results for full sample in bold, boys/girls in parentheses. R.C. Plotnikoff et al. / Journal of Adolescent Health 49 (2011) 547–549 549