Use of accelerometry to measure physical activity in older adults at risk for mobility disability

Abstract: We 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·d−1 ≥ 10 min above THRESHIND in the PA group compared to SA group (1.1 ± 2.0 vs 0.5 ± 0.8, p = 0.05) and more activity counts·d−1 above THRESHIND for the PA group (28,101 ± 27,521) compared to the SA group (17,234 ± 15,620, p = 0.02). Correlations between activity counts·hr−1 and CHAMPS ranged from 0.27 – 0.42, p<0.01. The ActiGraph and THRESHIND may be useful for differentiating PA levels in older adults at risk for mobility disability.