Responsiveness of the single item measure to detect change in physical activity.

Paul O’Halloran,Annemarie Wright,Kiera Staley,Adrian Bauman,Matthew Nicholson,Michael Kingsley,Erica Randle,Kathryn L Weston

doi:10.1371/journal.pone.0234420

Abstract

ObjectiveThe objective of this study was to evaluate the responsiveness of the single item measure (SIM) to detect change in PA when compared to hip-worn accelerometry. A secondary aim was to provide further data on validity of the measure at a single time point.MethodsValidity of the SIM to determine the number of days of ≥30 minutes of accelerometer-derived moderate-to-vigorous physical activity (MVPA) was assessed in 120 participants (78% female, 19% male, 3% other; age: 46 ± 11 years). Analysis of change was based on change in the number of days that participants completed ≥30 minutes of MVPA determined by the SIM and accelerometry over two 7-day periods in 90 participants (age: 47±11 years). Accelerometer data were analysed as total minutes of MVPA per day (MVPA-total) and as sustained bouts of 10 minutes or more of MVPA (MVPA-bouts). Validity of the SIM to detect change in MVPA, using accelerometer data as the reference measurement, was examined through Spearman’s correlation and agreement in classification of change between SIM and accelerometry. Responsiveness to change was assessed by standardised response means and Cohen’s d.ResultsStandardised response means for PA change were moderate for the SIM (0.77), MVPA-total (0.57) and MVPA-bouts (0.79). The correlation for change in number of days ≥30 minutes MVPA between the SIM and accelerometry were small to moderate (MVPA-total: r = 0.36 and MVP-bouts: r = 0.40). The SIM displayed moderate accuracy (60%-63%), using accelerometer data as the reference measurement, in detecting increases in days ≥30 minutes of MVPA.ConclusionThe SIM is a potentially useful assessment tool for evaluating change in MVPA, particularly when device-based measures or longer self-report measures are not feasible.

Highlights

Measurement of physical activity (PA) is important at a population level and for examining the effectiveness of large-scale interventions and programs designed to increase physical activity participation [1, 2]
Standardised response means for PA change were moderate for the single item measure (SIM) (0.77), MVPAtotal (0.57) and moderate-to-vigorous physical activity (MVPA)-bouts (0.79)
Responsiveness of the single item measure to change in physical activity data on the validity of the SIM compared to accelerometer data for assessing the number of days 30 minutes MVPA at a single time point

Summary

Introduction

Measurement of physical activity (PA) is important at a population level and for examining the effectiveness of large-scale interventions and programs designed to increase physical activity participation [1, 2]. Device-based measurement of PA using accelerometers is often the chosen method given supportive evidence of the validity and reliability of these instruments for assessing PA [3, 4]. The use of accelerometers is not always feasible due to expense, practical constraints, and poor compliance associated with these devices [5,6,7]. Self-report measures remain an option for measuring PA in large populations and for evaluation research [8,9,10]. The intended use of the measure and the feasibility of administration should be considered when selecting a self-report measure [3, 19]

Methods

Results

Conclusion