Type

Journal Article

Authors

Catherine M Phillips
Robert Kozarski
Kirsten L Rennie
Ivan J. Perry
Patricia M Kearney
Anthony P Fitzgerald
Christina B Dillon

Subjects

Physiotherapy & Sport

Topics
irish adults middle irish middle aged 5 years analysis and design physical activity sedentary behaviour self report

Number of Days Required to Estimate Habitual Activity Using Wrist-Worn GENEActiv Accelerometer: A Cross-Sectional Study. (2014)

Abstract Objective methods like accelerometers are feasible for large studies and may quantify variability in day-to-day physical activity better than self-report. The variability between days suggests that day of the week cannot be ignored in the design and analysis of physical activity studies. The purpose of this paper is to investigate the optimal number of days needed to obtain reliable estimates of weekly habitual physical activity using the wrist-worn GENEActiv accelerometer. Data are from a subsample of the Mitchelstown cohort; 475 (44.6% males; mean aged 59.6±5.5 years) middle-aged Irish adults. Participants wore the wrist GENEActiv accelerometer for 7-consecutive days. Data were collected at 100Hz and summarised into a signal magnitude vector using 60s epochs. Each time interval was categorised according to intensity based on validated cut-offs. Spearman pairwise correlations determined the association between days of the week. Repeated measures ANOVA examined differences in average minutes across days. Intraclass correlations examined the proportion of variability between days, and Spearman-Brown formula estimated intra-class reliability coefficient associated with combinations of 1-7 days. Three hundred and ninety-seven adults (59.7±5.5yrs) had valid accelerometer data. Overall, men were most sedentary on weekends while women spent more time in sedentary behaviour on Sunday through Tuesday. Post hoc analysis found sedentary behaviour and light activity levels on Sunday to differ to all other days in the week. Analysis revealed greater than 1 day monitoring is necessary to achieve acceptable reliability. Monitoring frame duration for reliable estimates varied across intensity categories, (sedentary (3 days), light (2 days), moderate (2 days) and vigorous activity (6 days) and MVPA (2 days)). These findings provide knowledge into the behavioural variability in weekly activity patterns of middle-aged adults. Since Sunday differed from all other days in the week this suggests that day of the week cannot be overlooked in the design and analysis of physical activity studies and thus should be included in the study monitoring frames. Collectively our data suggest that six days monitoring, inclusive of Saturday and Sunday, are needed to reliably capture weekly habitual activity in all activity intensities using the wrist-worn GENEActiv accelerometer.
Collections Ireland -> University College Cork -> PubMed

Full list of authors on original publication

Catherine M Phillips, Robert Kozarski, Kirsten L Rennie, Ivan J. Perry, Patricia M Kearney, Anthony P Fitzgerald, Christina B Dillon

Experts in our system

1
Catherine M Phillips
University College Cork
Total Publications: 44
 
2
Ivan J Perry
University College Cork
Total Publications: 188
 
3
Patricia M. Kearney
University College Cork
Total Publications: 128
 
4
Anthony P Fitzgerald
University College Cork
Total Publications: 73
 
5
Christina B Dillon
University College Cork
Total Publications: 14