ARTICLE IN PRESS Applied Ergonomics xxx (2009) 1–8
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Utility of the RT3 triaxial accelerometer in free living: An investigation of adherence and data loss Meredith A. Perry a, *, Paul A. Hendrick a, Leigh Hale a, G. David Baxter a, Stephan Milosavljevic a, Sarah G. Dean b,1, Suzanne M. McDonough c, Deirdre A. Hurley d a
Centre for Physiotherapy Research, University of Otago, PO Box 56, Dunedin, New Zealand, New Zealand Rehabilitation Teaching and Research Unit, University of Otago, Wellington, New Zealand, New Zealand Health & Rehabilitation Sciences Research Institute, University of Ulster, Northern Ireland d School of Physiotherapy and Performance Science, University College Dublin, Ireland b c
a r t i c l e i n f o
a b s t r a c t
Article history: Received 14 June 2009 Accepted 5 October 2009
There is strong evidence for the protective effects of physical activity on chronic health problems. Activity monitors can objectively measure free living occupational and leisure time physical activity. Utility is an important consideration when determining the most appropriate monitor for specific populations and environments. Hours of activity data collected, the reasons for activity hours not being recorded, and how these two factors might change over time when using an activity monitor in free living are rarely reported. This study investigated user perceptions, adherence to minimal wear time and loss of data when using the RT3 activity monitor in 21 healthy adults, in a variety of occupations, over three (7 day) repeated weeks of measurement in free living. An activity diary verified each day of monitoring and a utility questionnaire explored participant perceptions on the usability of the RT3. The RT3 was worn for an average of 14 h daily with 90% of participants having complete data sets. In total 6535.8 and 6092.5 h of activity data were collected from the activity diary and the RT3 respectively. An estimated 443.3 h (6.7%) of activity data were not recorded by the RT3. Data loss was primarily due to battery malfunction (45.2%). Non-adherence to wear time accounted for 169.5 h (38.2%) of data loss, of which 14 h were due to occupational factors. The RT3 demonstrates good utility for free living activity measurement, however, technical issues and strategies to manage participant adherence require consideration with longitudinal and repeated measures studies. Ó 2009 Elsevier Ltd. All rights reserved.
Keywords: Adherence Usability Physical activity Data loss Triaxial accelerometer
1. Introduction There is increasing evidence for the benefits of both occupational physical activity (PA) and sport and leisure time PA on a range of health outcomes (Hildebrandt et al., 2000; Bauman, 2004; Zhang et al., 2006; Probert et al., 2008) including benefits in cardiovascular disease, diabetes, stroke, mental health and musculoskeletal disorders. Occupational activity (or the physical requirements of the job) and occupational inactivity have been shown to influence the risk of
* Corresponding author. Tel.: þ64 4 3855357; fax: þ64 4 43855427. E-mail addresses: meredith.perry@otago.ac.nz (M.A. Perry), paul.hendrick@ otago.ac.nz (P.A. Hendrick), leigh.hale@otago.ac.nz (L. Hale), physio.dean@otago.ac. nz (G.D. Baxter), stephan.milosavljevic@otago.ac.nz (S. Milosavljevic), sarah.dean@ otago.ac.nz, sarah.dean@pms.ac.uk (S.G. Dean), s.mcdonough@ulster.ac.uk (S.M. McDonough), deirdre.hurleyosing@ucd.ie (D.A. Hurley). 1 Permanent address: Sarah Dean, Peninsula Medical School, St Luke’s Campus, Universities of Exeter and Plymouth, United Kingdom.
musculoskeletal work related disorders (Chan et al., 2004; Marras et al., 2009). Musculoskeletal work related disorders are thought to arise from prolonged periods of exposure to repetitive specific high or low load tasks causing tissue fatigue (Westgaard and Winkel, 1996), coupled with a combination of other psychological and sociological factors (Marras et al., 2009). Exploring the accuracy and utility of methods to measure occupational activity is necessary for understanding the relative contribution of this specific work related factor to occupational physical disorders. Activity monitors are a common objective measure employed to assess PA in a range of populations and occupational settings (Busser et al., 1998; Ainsworth et al., 1999; Estill et al., 2000; Heil, 2002; Cuthill et al., 2008; Dall and Kerr, 2009) and in a variety of patient populations such as people with cardiovascular disease, neurological disability, and cancer survivors (Steele et al., 2000, 2003a,b; Balogh et al., 2004; Hertzog et al., 2007; Hale et al., 2008; Sloane et al., 2009; Jerome et al., 2009). More recently, activity monitors have been used to assess the PA of people with musculoskeletal
0003-6870/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.apergo.2009.10.001
Please cite this article in press as: Perry, M.A., et al., Utility of the RT3 triaxial accelerometer in free living: An investigation of adherence and data loss, Applied Ergonomics (2009), doi:10.1016/j.apergo.2009.10.001