Issues in accelerometer methodology: the role of epoch length on estimates of physical activity and relationships with health outcomes in overweight, post-menopausal women

Table 3 Agreement between quartiles of accelerometer data^† expressed using 60 and 10 second (s) epoch intervals collected in WOMAN Study Participants at the 48 month follow-up visit (n = 102).

	Kendall's tau-b	95% Confidence Limits
Inactivity: wear time	0.90	0.86, 0.95
Inactivity (0-99 ct), min/day^††	0.88	0.82, 0.93
Light Intensity (100-<2020 ct), min/day	0.87	0.82, 0.92
Moderate Intensity (2020-<5999 ct), min/day	0.85	0.79, 0.90
Vigorous Intensity (≥5999 ct) ^†, min/day	---	---
MVPA (≥2020 ct), min/day	0.86	0.80, 0.91

Quartile ranges created using median (interquartile range) that are presented in table 1 for light-, moderate-, vigorous, and moderate- to vigorous- intensity physical activity. Quartile ranges for inactivity were <471.6, ≥471.6-<527.4, ≥527.4-<580.1, and ≥580.1 for 60 second epoch data and <583.5, ≥583.5-<632.1, ≥632.1-<665.8, and ≥665.8 for 10 second epoch data.
^†Unable to compute, median (IQR) for vigorous- intensity physical activity collected in 60s epochs was 0 (0.0, 0.0)
^††Presented as the ratio between inactivity and wear time.

ISSN: 1479-5868