Date of Award


Document Type

Campus Access Dissertation

Degree Name

Doctor of Philosophy (PhD)


Exercise and Health Science

First Advisor

Jessica Whiteley

Second Advisor

Julie Wright

Third Advisor

Mario Munoz


Objectives: The purpose of this mixed method study is to develop a novel, valid, and reliable questionnaire that assesses processes of change relating to adolescent physical activity behavior during early adolescence (11-14 years old). In qualitative phase of this study, sixteen adolescents were interviewed to achieve a better understanding about the processes they use for changing their physical activity behavior. Processes of Change Questionnaire for Youth (PCQ-Y) was constructed based on the results from the qualitative data. After content validity and cognitive interview processes, 315 adolescents completed PCQ-Y as well as Stage of Exercise Change Questionnaire (SECQ) via Qualtrics panel. Construct validity of the scale was tested using Partial Least Squares- Structural Equation Model, Confirmatory Factor Analysis (PLS-SEM, CFA), convergent and discriminant validities. Internal consistency was tested by calculating Cronbach’s alpha and composite reliability scores. Finally, a multivariate analysis of variance (MANOVA) was performed to analyze the overall variations of POCs across SOC and assess the criterion validity of PCQ-Y. Results: A pool of 92 potential items were generated from interviews. Content validity and cognitive interview processes resulted in 55 final items. A total of 315 (199 girls; 116 boys) adolescents with a mean age of 12.7 years filled out the PCQ-Y. The results showed that 235 adolescents were in maintenance stage, 45 in action, 12 in preparation, 10 in contemplation, and 13 in precontemplation. Construct validity of PCQ-Y was established since all items had the satisfactory loading factor of at least 0.5 with t >1.65. Each POC had average variance extracted (AVE) value greater than 0.5 and the square root of AVE for PCQ-Y items load more strongly on their corresponding process than on other processes. The PCQ-Y possesses good internal consistency reliability for each process with values greater than .70. In addition, significant differences were revealed in use of processes of change constructs through stages of physical activity which confirmed criterion validity. Conclusion: These data support the validity and reliability of the POC-Y in physical activity among an adolescent sample. More research is needed to explore the longitudinal properties of this scale.


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