Influence of cut-points on patterns of accelerometry-measured free-living physical activity in rural and urban black South African women.

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.