Influence of Cut-Points on Patterns of Accelerometry-Measured Free-Living Physical Activity in Rural and Urban Black South African Women

Abstract

Background:We describe the effect of 2 different accelerometer cut-points on physical activity (PA) patterns in rural and urban black South African women.Methods:Hip-mounted uni-axial accelerometers were worn for 6 to 7 days by rural (n = 272) and urban (n = 16) participants. Twenty-hour (4 AM to 12 AM) PA counts (cts) and volumes (min·day−1) were extracted: sedentary (SED, <100 cts·min−1), light (100–759 cts·min−1), moderate-1 (MOD1, 760–1951 cts·min−1), moderate-2 to vigorous (MOD2VG, ≥1952 cts·min−1), and bouts ≥10 min for ≥760 cts·min−1 (MOD1VGbt) and ≥1952 cts·min−1 (MOD2VGbt).Results:Valid data were obtained from 263 rural women and 16 urban women. Total counts and average counts were higher (+80,399 cts·day−1, +98 cts·min−1.day−1) (P < .01), SED lower (−61 min·day−1, P = .0042), MOD1 higher (+65 min·day−1, P < .0001), and MOD1VGbt higher (+19 min·day−1, P = .0179) in rural women compared with urban women. Estimated adherence (≥30 min·day−1 for 5 days·wk−1) was 1.4-fold higher in rural women than urban women for MOD-1VGbt, but 3.3-fold higher in urban women than rural women for MOD2VGbt.Conclusions:Rural women accumulate greater amounts of PA than urban women within a particular count band. Depending on which moderate PA cut-point was used to estimate PA public health adherence, rural women could be classified as less physically active than urban women.