Physical Activity Assessment

Background

Physicians report that they fail to counsel patients about physical activity due to a lack of practical tools, time, reimbursement, knowledge, and confidence. This paper reports concurrent and criterion validation of the Physical Activity Assessment Tool (PAAT), designed to rapidly assess patient physical activity in clinical settings and reduce time for assessment, and thus to facilitate counseling.

Methods

Adult volunteers (n=68) completed the PAAT and International Physical Activity Questionnaire-Long Form (IPAQ-Long) twice and wore a Manufacturing Technology, Inc. (MTI) accelerometer for 14 days in 2003. Continuous and categorical measures of physical activity by PAAT were compared to MTI accelerometer and IPAQ-Long in analyses conducted in 2003 to 2006. Consistent with national recommendations, participants were classified as active if they accumulated more than 150 minutes per week of moderate to vigorous physical activity (MVPA) or more than 60 minutes per week of vigorous physical activity.

Results

The PAAT was significantly correlated with the IPAQ (r=0.562, p<0.001) and MTI (r=0.392, p=0.015) for MVPA. Seven-day test–retest reliability was comparable for PAAT (r=0.618, p<0.001) and MTI (r=0.527, p<0.001). PAAT classified participants as “active” or “under-active” concordantly with MTI for 69.8% of participants and with IPAQ for 66.7%; strength of agreement was fair (κ=0.338 and 0.212, respectively). The PAAT classified fewer participants as active than either the MTI (p=0.169) or IPAQ (p<0.001), and measured physical activity more like the direct objective measure (MTI) than did IPAQ.

Conclusions

The concurrent and criterion validity of the PAAT are comparable to self-report instruments used in epidemiologic research.

Introduction

Because of the salutary health effects of physical activity,1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 the U.S. Surgeon General, Centers for Disease Control and Prevention, and American College of Sports Medicine recommend that American adults should get at least 30 minutes of moderate-intensity physical activity (MPA) in bouts of 10 or more minutes on most days of the week or 20 minutes of vigorous physical activity (VPA) on 3 or more days each week.1, 2 Although physician counseling appears to be modestly effective for short-term increases in patient physical activity, it remains uncertain how counseling should be done to elicit more durable changes in physical activity.12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 Nonetheless, Healthy People 2010²⁹ recommended physician counseling for physical activity, and because 82% of people see a physician every year, the potential public health impact of physician counseling could be significant even if it is only modestly effective. Yet 52% to 78% of patients report that they have not been counseled about physical activity by their physicians.30, 31, 32, 33, 34, 35 Physicians report that they do not counsel patients because of a lack of practical tools, time, reimbursement, knowledge, and confidence that counseling will trigger behavior change.1, 2, 32, 36

The self-administered Physical Activity Assessment Tool (PAAT) (Figure 1) was developed to rapidly assess patient physical activity in primary care settings, reduce physician time for assessment, facilitate counseling, and address physician knowledge and confidence deficits. The PAAT defines moderate and vigorous physical activity, and incorporates questions used in International Physical Activity Questionnaire (IPAQ) Short form³⁷ with lists of common types of physical activity that are stratified by intensity according to the updated Compendium of physical activity.³⁸ The PAAT measures type, frequency, and duration of moderate and vigorous physical activity from all four domains of physical activity—leisure, occupational, household, and transportation—in the last 7 days, and asks if this is “more, less, or about the same as usual” activity. The PAAT can be completed in 5 to 7 minutes while patients wait to see a physician. It includes questions about possible contraindications to physical activity, stage of change, patient-oriented benefits, and psychosocial facilitators of physical activity. This paper describes validation of self-reported physical activity by PAAT against a direct, objective measure of physical activity—the Manufacturing Technology, Inc. (MTI, formerly Computer Science and Applications, Inc. [CSA]) accelerometer39, 40, 41, 42, 43, 44, 45, 46—and a previously validated, self-report instrument—the IPAQ-Long Form, Self Administered.³⁷