Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Randomized Controlled Trial
. 2018 Apr 17;73(5):660-667.
doi: 10.1093/gerona/glx132.

Evaluating Accelerometry Thresholds for Detecting Changes in Levels of Moderate Physical Activity and Resulting Major Mobility Disability

W Jack Rejeski  1 , Michael P Walkup  2 , Roger A Fielding  3 , Abby C King  4 , Todd Manini  5 , Anthony P Marsh  1 , Mary McDermott  6 , Emily Y Miller  2 , Anne B Newman  7 , Catrine Tudor-Locke  8 , Robert S Axtell  9 , Michael E Miller  2 ; LIFE Study Investigators
Affiliations
Randomized Controlled Trial

Evaluating Accelerometry Thresholds for Detecting Changes in Levels of Moderate Physical Activity and Resulting Major Mobility Disability

W Jack Rejeski et al. J Gerontol A Biol Sci Med Sci. .

Abstract

Background: An important decision with accelerometry is the threshold in counts per minute (CPM) used to define moderate to vigorous physical activity (MVPA). We explore the ability of different thresholds to track changes in MVPA due to a physical activity (PA) intervention among older adults with compromised function: 760 CPM, 1,041 CPM, and an individualized threshold. We also evaluate the ability of change in accelerometry and self-reported PA to attenuate treatment effects on major mobility disability (MMD).

Methods: Data from a week of hip worn accelerometers and self-reported PA data (30-day recall) were examined from baseline, 6-, 12-, and 24-months of follow-up on 1,528 older adults. Participants were randomized to either PA or Health Education (HE). MMD was objectively defined by loss of ability to walk 400 m during the follow-up.

Results: The three thresholds yielded similar and higher levels of MVPA for PA than HE (p < .001), however, this difference was significantly attenuated in participants with lower levels of physical function. Self-reported PA that captured both walking and strength training totally attenuated the intervention effect for MMD, an 18% reduction to a 3% increase. Accelerometer CPMs showed less attenuation of the intervention effect.

Conclusions: Accelerometry assessment within the LIFE study was not sensitive to change in level in physical activity for older adults with very low levels of physical function. A combination of self-report and objective measures are recommended for use in physical activity intervention studies of the elderly; limitations of accelerometry deserve closer attention.

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
Minutes of MVPA per week using an individualized threshold, 760 CPM and 1,041 CPM.
Figure 2.
Figure 2.
Minutes of MVPA per week for different thresholds by quartiles of physical function (1st is fastest and 4th is slowest) of physical function (ie, 400 m walk time).
Figure 3.
Figure 3.
Minutes of MVPA per week by quartiles of physical function.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Healy GN, Dunstan DW, Salmon J et al. . Breaks in sedentary time: beneficial associations with metabolic risk. Diabetes Care. 2008;31:661–666. doi:10.2337/dc07-2046 - PubMed
    1. Azevedo LF, Dos Santos MR. High-intensity intermittent exercise training for cardiovascular disease. J Novel Physiother. 2014;4:1–8. doi:10.4172/2165-7025.1000199
    1. Nelson ME, Rejeski WJ, Blair SN et al. ; American College of Sports Medicine; American Heart Association. Physical activity and public health in older adults: recommendation from the American College of Sports Medicine and the American Heart Association. Circulation. 2007;116:1094–1105. doi:10.1161/CIRCULATIONAHA.107.185650 - PubMed
    1. Rejeski WJ, Marsh AP, Brubaker PH et al. ; LIFE Study Investigators. Analysis and interpretation of accelerometry data in older adults: The LIFE study. J Gerontol A Biol Sci Med Sci. 2016;71:521–528. doi:10.1093/gerona/glv204 - PMC - PubMed
    1. Freedson PS, Melanson E, Sirard J. Calibration of the Computer Science and Applications, Inc. accelerometer. Med Sci Sports Exerc. 1998;30:777–781. doi:10.1097/00005768-199805000-00021 - PubMed

Publication types