How to apply a measure to use in a different population?


Research clearly highlights the health-related benefits of participation in daily physical activity (PA), including prevention and treatment of chronic diseases such as obesity, type 2 diabetes, hypertension, cardiovascular disease, and some forms of cancer. Despite the known benefits of PA, the majority of U.S. adults do not achieve the recommended 150–300 minutes per week of moderate-intensity or 75 weekly minutes of vigorous-intensity PA. National surveillance data show that Black populations participate in less PA and have higher rates of chronic disease than their white counterparts. Data in Black populations show that PA participation is lowest among Black girls and women vs. Black boys and men, despite personal characteristics such as weight status, education, income, and geographic location.

This case study describes recruitment and pre-screening activities to evaluate eligibility of African American women who want to participate in a community-based physical activity intervention. The study is recruiting women who are insufficiently active, meaning they are not currently achieving the 2018 Physical Activity Guidelines of 150 minutes per week of moderate-to-vigorous aerobic physical activity. The recruitment and pre-screening process requires women to self-report physical activity participation to determine eligibility. Selecting a validated measure to screen women that has been used in other populations is desirable in this context because of budget and time restrictions but has some challenges as described below.

Considerations and challenges

How can the research team accurately measure physical activity prior to the start of the study?

The study design does not allow for objective monitoring of physical activity prior to enrollment, so the study team will need to rely on self-report measures for pre-screening for insufficiently active women. Thus the team will need to identify a self-report assessment tool that would allow participants to quickly and accurately provide a self-assessment of physical activity participation. In addition to objective measures used to assess PA during the study, the team plans to use the self-report tool as a secondary measure to assess change in PA from pre-screen and pre-post intervention.

How will the study team take into account that, among racial/ethnic minority communities, physical activity can take all forms, including leisure-time, occupation-related, and physical activity for transportation throughout the week?

The team wants to utilize a questionnaire that assesses multiple domains of activity. Many physical activity questionnaires ask about leisure time physical activity, and qualitative data from studies about perceptions of physical activity suggest that racial/ethnic minority women perceive that they have limited time for leisure and that social roles impede participation in leisure-time physical activity. Thus, surveys that focus solely on leisure time could mask participation in other physical activity domains (e.g., walking for transportation, occupation-related physical activity).

Will participants be able to accurately interpret key concepts required to assess the outcomes? (e.g., what “moderate” or “vigorous” mean in terms of intensity and estimate bouts of physical activity lasting 10 minutes in length?)

The study team desires a way to convey both intensity level and bout length in ways that participants could immediately and easily understand. Ideally, the instructions would increase participant accuracy on the self-report measure.

Measure Selection

The team selected a familiar instrument for screening, the. IPAQ is a self-report tool that assesses vigorous-intensity, moderate-intensity, and walking physical activity as well as sedentary time via open ended questions during a typical week (7-day period) across multiple domains of activity. The IPAQ is available in NCCOR’s Measures Registry. The IPAQ has been validated in a number of population subgroups, including Blacks. IPAQ assesses adherence to national recommendations for moderate and vigorous physical activity during the previous 7 days. Two questions assess days per week and time per session for vigorous or moderate activity lasting 10 minutes or more per session. Three questions assess daily and brisk walking at work, at home, for transportation, and for recreation, sport, exercise, or leisure for 10 minutes or more per session.

The study team recognized from prior work in this population that individuals who engage primarily in non-leisure physical activity (e.g., housework, occupational activity) that does not have a specific start and end time may over- or underestimate their participation in such activities. The study team hypothesized that making a few key modifications to the survey might improve participant response accuracy, and they create a modified version of the modifications:

  1. Prior to completing the m-IPAQ, the study team engaged participants in a 10-minute structured bout of moderate-intensity physical activity. The rationale was to ensure that participants were able to accurately interpret what a 10-minute bout of physical activity felt like. For consistency, the study team used a 10-minute moderate-intensity Instant Recess® break as an “orientation.” The Instant Recess break concept provides opportunities for individuals to participate in 10-minute bouts of physical activity. Instant Recess is designed to be performed anywhere, anytime, in any type of attire. The breaks consist of a series of basic aerobic dance, calisthenics, and sports movements. Moves are moderate intensity, low-impact, and are performed in 10-minute bouts set to music. The instructions for moves are called out during the routine, and participants are asked to follow along. Following the 10-minute exercise break, study participants were told to keep the activity in mind as they completed the m-IPAQ.
  2. The study team asked about usual physical activity instead of physical activity in the past 7 days. This change was made because several times during recruitment, unusual occurrences (e.g., vacation, conference travel, extreme weather) would have negatively impacted activities during the previous 7 days and, thus, might have prevented an accurate representation of physical activity.
  3. The study team changed the open-ended questions related to frequency to closed-ended questions. Participants selected days per week from a list ranging from 0 days to 7 days. The study team also modified the questions on duration of physical activity from an open-ended response to categorical responses to try to reduce overestimation: “I do not do _____ activity for more than 10 minutes in a row”; “10 to 15 minutes”; “16 to 30 minutes”; “31 to 45 minutes”; “46 to 60 minutes”; and “over 60 minutes.” To calculate a continuous measure of physical activity participation, minutes per day are estimated as 0, 10, 16, 31, 46, and 60.

Lessons Learned

  • The resulting m-IPAQ, combined the with Instant Recess orientation, helped participants to more accurately reflect on and respond to the self-report questionnaire. Anecdotally, participants indicated that they though the 10-minute exercise bout was actually closer to 20 or 30 minutes and expressed surprise at how moderate-intensity activity felt. They also noted that the orientation helped them to better understand how to respond to the m-IPAQ questions. The participants’ comments suggest that participants might have overestimated their participation in physical activity prior to the Instant Recess orientation, as evidenced by participants who believed they had performed two to three times as much physical activity as they actually had performed. Engaging participants in a 10-minute bout of physical activity prior to asking participants to complete a self-reported physical activity questionnaire could be a useful strategy for level setting participants’ perceptions about physical activity and for improving self-report accuracy. Using the Instant Recess video also provided an opportunity for participants in the recruitment process to break up a long bout of sitting and allowed the study team to model strategies for reducing sedentary time. The Instant Recess video was easy to use, and all study team members were able to successful lead the pre-survey physical activity break.
  • Asking about usual physical activity, rather than the past 7 days, reduced questions from participants who had unusual circumstances. Recruitment for the study described occurred over a nearly one-year period, and there were several occurrences of vacations and inclement weather that impacted physical activity during the previous 7 days. Some participants also mentioned unusual changes in work schedules or caregiving responsibilities. Asking participants to report on their usual physical activity participation seemed to eliminate participant’s concerns about whether their data would be accurate.
  • Using the close-ended responses for days per week and minutes per day at each physical activity intensity level decreased the amount of time participants took to complete the survey and increased the speed at which study staff could calculate results and determine participant eligibility. The close-ended questions meant there was limited data cleaning (other than confirming if participants skipped questions), so results could be captured immediately after data were entered. This accelerated process made it easier to recruit and enroll participants for the study.
  • Given the popularity of the Instant Recess activity, the query of usual physical activity, and the ease of calculating results from close-ended questions, the study team plans to continue to use the m-IPAQ for pre-screening and data collection for future physical activity studies.

Related Resources

  • Williams WM, Yore MM, Whitt-Glover MC. Estimating physical activity trends among blacks in the United States through examination of four national surveys. AIMS Public Health. 2018;5(2):144-157. doi: 10.3934/publichealth.2018.2.144
  • Whitt-Glover MC, Taylor WC, Floyd MF, Yore MM, Yancey AK, Matthews CE. Disparities in physical activity and sedentary behaviors among U.S. children and adolescents: Prevalence, correlates, and intervention implications. J Public Health Pol. 2009;30(Supplement 1):S309 – S334. doi: 10.1002/nur.20393
  • Sebastião E, Chodzko-Zajko W, Schwingel A. The need to modify physical activity messages to better speak to older African American women: a pilot study. BMC Public Health. 2015;15:962. doi: 10.1186/s12889-015-2317-x
  • Warren TY, Wilcox S, St George SM, Brandt HM. African American Women’s Perceived Influences on and Strategies to Reduce Sedentary Behavior. Qual Health Res. 2018;28(7):1112-1122. doi: 10.1177/1049732317748605
  • Craig CL, Marshall AL, Sjostrom M, et al. International Physical Activity Questionnaire (IPAQ): 12-country reliability and validity. Med Sci Sports Exerc. 2003;35(8):1381-1395. . doi:10.1249/01.MSS.0000078924.61453.FB
  • Lee PH, Macfarlane DJ, Lam TH, Stewart SM. Validity of the International Physical Activity Questionnaire Short Form (IPAQ-SF): a systematic review. Int J Behav Nutr Phys Act. 2011;8:115. doi:10.1186/1479-5868-8-115
  • Hallal PC, Gomez LF, Parra DC, et al. Lessons learned after 10 years of IPAQ use in Brazil and Colombia. J Phys Act Health. 2010;7 Suppl 2:S259-264. doi:10.1123/jpah.7.s2.s259
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