The purpose of the study was to investigate whether a 24-hr recording period is sufficient to describe physical activity (PA) of 1 week for intraindividual comparison in older adults. Furthermore, the authors analyzed whether physical performance can be used as a surrogate marker of PA. PA was captured on 7 consecutive days by a body-fixed sensor in 44 community-dwelling older adults (80.75 ± 4.05 yr). Mean times of walking and of “time on feet” of the group were 10.2 hr (± 3.5) and 35.1 hr (± 9.43), respectively. Intraindividual variabilities of walking and of time on feet were 31.9% ± 10.79% and 19.4% ± 8.76%, respectively. Accumulated time of variables of PA showed no differences between weekdays, with variabilities of 3.8% and 1.8% for walking and time on feet, respectively. Association between Short Physical Performance Battery and PA was limited (walking r = .397, time on feet r = .41).
Simone Nicolai, Petra Benzinger, Dawn A. Skelton, Kamiar Aminian, Clemens Becker and Ulrich Lindemann
Klaus Hauer, Stephen R. Lord, Ulrich Lindemann, Sarah E. Lamb, Kamiar Aminian and Michael Schwenk
The purpose of this study was to validate a new interview-administered physical activity questionnaire (Assessment of Physical Activity in Frail Older People; APAFOP) in older people with and without cognitive impairment. The authors assessed feasibility, validity, and test–retest reliability in 168 people (n = 78 with, n = 88 without cognitive impairment). Concurrent validity was assessed against an inertia-based motion sensor and an established questionnaire. Sensitivity to change was tested in an ongoing study in patients with mild to moderate dementia (n = 81). Assessment of physical activity by the APAFOP and the motion sensor correlated well in the total sample (TS; p = .705), as well as in the subsamples with cognitive impairment (CI; p = .585) and without CI (p = .787). Excellent feasibility with an acceptance rate of 100%, test–retest reliability (intraclass correlation coefficients ranging from .973 (TS) to .975 (CI) to .966 (no CI), and sensitivity to change (effect sizes: 0.35–1.47) were found in both subsamples.