Accelerometry Cutpoints and Older Adults: A Systematic Review

Introduction Most accelerometry research is in children and adults. Literature on accelerometry in older adults is limited and many studies rely on validity studies completed on younger adults to determine cutpoints for exercise intensity. The purpose of this study was: to review the literature to identify studies that used ActiGraph accelerometers to assess moderate-to-vigorous physical activity (MVPA) in older adults; and 2) to determine the effect of changing reported cutpoints on meeting guideline recommendations for MVPA.

Methods We completed an electronic literature search for accelerometers, physical activity, and older adults. We limited our search to English language and adults aged 65 years+. We included studies that used ActiGraph accelerometers (Pensacola, FL) at the waist and cutpoints for exercise intensity. Data extracted identified the study design, participant characteristics and accelerometry methods. We then analyzed accelerometry data (GT1M) from active older women (65-75 years) using different cutpoints from the literature to determine meeting guidelines as ≥ 30 minutes MVPA/day. Data were a sample from an RCT to test the effect of frequency of resistance training. Participants wore accelerometers for 1 week (1 minute epoch with inclusion of at least 4 days with 10+ hours/day).

Results There are a limited number of articles that have used accelerometry in older adults. The majority of cutpoints for MVPA used for this age group ranged between 1952 to 2020 counts/minute. We identified two other cutpoints that included older adults in their calculation and used these three cutpoints (Swartz=574 counts/minute [1], Copeland=1041 counts/minute [2], Freedson=1952 counts/minute [3]) to analyze our data. 114 participants had valid data and their mean age was 69.6(2.9) years and mean BMI was 26.6 (5.0) kg/m². The following amount of MVPA was obtain from the different analyses; Swartz=84.7(41.8) minutes/day, Copeland=47.2(29.0) minutes/day and Freedson=23.9(20.6) minutes/day. These values result in 108(95%), 73(64%) and 38(33%) participants meeting MVPA guidelines respectively.

Discussions and Conclusions Accelerometers provide valuable information regarding physical activity but, the analysis of data can alter observed findings. The majority of studies have used similar cutpoints which allows for comparison, however, these cutpoints are not age or ability specific and may not accurately represent the amount of MVPA for all older adults.

References [1] Swartz AM, Strath SJ, Bassett DR Jr., O’Brien WL, King GA, Ainsworth BE. Estimation of energy expenditure using CSA accelerometers at hip and wrist sites. Med Sci Sports Exerc, 2000; 32: S450-456. [2] Copeland JL, Esliger DW. Accelerometer assessment of physical activity in active, health older adults. J Aging Phys Act, 2009; 17: 17-30. [3] Freedson PS, Melanson E, Sirand J. Calibration of the computer science and applications, inc. accelerometer. Med Sci Sports Exerc, 1998; 30: 777-781.