Use of Accelerometry to Measure Physical Activity in Older Adults at Risk for Mobility Disability

Abstract

The authors explored using the ActiGraph accelerometer to differentiate activity levels between participants in a physical activity (PA,n= 54) or “successful aging” (SA) program (n= 52). The relationship between a PA questionnaire for older adults (CHAMPS) and accelerometry variables was also determined. Individualized accelerometry-count thresholds (ThreshIND) measured during a 400-m walk were used to identify “meaningful activity.” Participants then wore the ActiGraph for 7 days. Results indicated more activity bouts/day ≥10 min above ThreshINDin the PA group than in the SA group (1.1 ± 2.0 vs 0.5 ± 0.8,p= .05) and more activity counts/day above ThreshINDfor the PA group (28,101 ± 27,521) than for the SA group (17,234 ± 15,620,p= .02). Correlations between activity counts/hr and CHAMPS ranged from .27 to .42,p< .01. The ActiGraph and ThreshINDmight be useful for differentiating PA levels in older adults at risk for mobility disability.