Comparing Measures of Physical Activity Intensity, Duration, and Frequency Using Receiver Operator Characteristic Curve Analyses

Comparing Measures of Physical Activity Intensity, Duration, and Frequency Using Receiver Operator Characteristic Curve Analyses Abigail M. Nehrkorn-Bailey The United States Department of Health and Human Services (HHS) recommends adults to engage in weekly moderateor vigorous-intensity physical activity based on its association with various physical and psychological health benefits (HHS, 2008; Schoenborn, Adams, & Peregoy, 2013). These physical activity recommendations contain important information for three physical activity components: intensity, frequency, and duration. The current physical activity literature contains gaps, with a lack of specificity for which components are being studied. Although some of the literature does describe the physical activity components, there are many discrepancies in the level of agreement across subjective and objective measures, along with the same basic analyses being utilized across studies. With data from 56 adults (Mage = 43.2, SD = 16.5), receiver operator characteristic (ROC) curve analyses were conducted for two weeks’ data to assess the agreement between a one-week recall questionnaire, daily diary accounts, and accelerometer data for the three physical activity components (intensity, frequency, and duration). For intensity and duration of physical activity, the worst agreement existed between the accelerometer and questionnaire, with the area under the curve (AUC) indicating chance agreement at best (AUC = 0.447-0.598); the accelerometer and daily diary measures generally exhibited chance-to-poor agreement (AUC = 0.331-0.671); and the daily diary and questionnaire showed the largest range from chance-to-good agreement (AUC = 0.4820.794). The strongest agreement was shown for frequency of physical activity, especially for mild-intensity physical activity (AUC = 0.836) at Week 2. Across moderate-to-vigorous-, mild-, and sedentary-intensity behaviors, participants experienced the worst agreement for sedentary behaviors (AUC = 0.331-0.686), with most of the sedentary-specific intensity, frequency, and duration AUC scores showing chance agreement. The current study significantly expands and adds to the literature by focusing on all three physical activity components across moderate-tovigorous-, mild-, and sedentary-intensity activities, as well as utilizing advanced analyses to assess the agreement between two subjective measures and one objective measure. The findings highlight the importance of educating adults about the physical activity components, different intensities, and methods of tracking and reporting activity. PHYSICAL ACTIVITY INTENSITY, DURATION, AND FREQUENCY iii Acknowledgements The support I have received from my mentor, professors, friends, and family has propelled me to this milestone. Their positivity, encouragement, and knowledge will never be forgotten. First, I would like to thank my mentor Dr. Julie Hicks Patrick. Dr. Patrick’s instruction carried through to my writing, research, and knowledge of the field. However, her mentoring and support also helped me to strengthen my passion for the field and to realize the vision I had for my academic future. Connectedly, I am grateful to my many professors, graduate school friends, and lab members for their constant encouragement. I also want to thank my Midwestern friends, family, and godson Leo for their love and support from afar. Special thanks go to my dad Steve Nehrkorn for his constant belief in me and my continued endeavors. A special thank you also goes to my sister Amanda Nehrkorn Jacobson. As your prodigy from a young age, you’ve always believed in me. Without your constant love, support, and visits, I would not be writing this acknowledgement. Dad and Amanda, your belief in me has paid off! Lastly, I want to thank my husband Zach Bailey. Zach, your love and support has helped me to achieve so much. Thank you for always supporting me and my passion. PHYSICAL ACTIVITY INTENSITY, DURATION, AND FREQUENCY iv Table of