How many consecutive days of pedometer monitoring is required to estimate weekly physical activity levels of young healthy adults?

Abstract

Introduction: Pedometers are an inexpensive and convenient way to measure physical activity. Several studies have suggested that 3–5 days of pedometer monitoring are required for accurate and reliable estimates of daily physical activity levels in mature adults. However, the minimum number of days of monitoring needed to estimate total physical activity over a week for young adults is unknown. The aim of the current study was to determine the number of consecutive days needed to estimate weekly pedometer-based, physical activity levels for young healthy adults.Methods: Eighty-two (31 males, 51 females) healthy adults volunteered for this study (age 20.4 ± 4.1 yrs). All participants provided informed written consent prior to participation with all procedures conducted in accordance with approval of the local university Human Ethics Sub-Committee. Participants wore a Yamax Digi-Walker SW-700 pedometer (Yamax, Japan) on their waist for seven consecutive days during wakeful hours (except water based activities). At the end of each day, participants recorded the number of steps taken. Differences in daily physical activity were determined via 1-way ANOVA while estimates of weekly physical activity were assessed via linear stepwise regression.Results: Significantly less physical activity was undertaken on Sunday compared to Monday and Thursday (p < 0.05). Stepwise regression analysis identified that one day (Wednesday) accounted for 48.1% of the model variance with two (Wednesday–Thursday), three (Wednesday–Friday), four (Saturday–Tuesday) and five (Wednesday–Sunday) consecutive days accounting for 64.9%, 79.2%, 85.5% and 93.5% of the model variance.Discussion: The results of the current study suggest that five consecutive days (Wednesday–Sunday) will accurately estimate total weekly physical activity level based on pedometer measures in young adults. Introduction: Pedometers are an inexpensive and convenient way to measure physical activity. Several studies have suggested that 3–5 days of pedometer monitoring are required for accurate and reliable estimates of daily physical activity levels in mature adults. However, the minimum number of days of monitoring needed to estimate total physical activity over a week for young adults is unknown. The aim of the current study was to determine the number of consecutive days needed to estimate weekly pedometer-based, physical activity levels for young healthy adults. Methods: Eighty-two (31 males, 51 females) healthy adults volunteered for this study (age 20.4 ± 4.1 yrs). All participants provided informed written consent prior to participation with all procedures conducted in accordance with approval of the local university Human Ethics Sub-Committee. Participants wore a Yamax Digi-Walker SW-700 pedometer (Yamax, Japan) on their waist for seven consecutive days during wakeful hours (except water based activities). At the end of each day, participants recorded the number of steps taken. Differences in daily physical activity were determined via 1-way ANOVA while estimates of weekly physical activity were assessed via linear stepwise regression. Results: Significantly less physical activity was undertaken on Sunday compared to Monday and Thursday (p < 0.05). Stepwise regression analysis identified that one day (Wednesday) accounted for 48.1% of the model variance with two (Wednesday–Thursday), three (Wednesday–Friday), four (Saturday–Tuesday) and five (Wednesday–Sunday) consecutive days accounting for 64.9%, 79.2%, 85.5% and 93.5% of the model variance. Discussion: The results of the current study suggest that five consecutive days (Wednesday–Sunday) will accurately estimate total weekly physical activity level based on pedometer measures in young adults.