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Table 2 Number of complete data acquisition days needed to predict 21 days of physical activity behavior from objective and subjective methodologies as determined by Spearman Brown Prophecy Formula.

From: How many days of monitoring predict physical activity and sedentary behaviour in older adults?

  ActiGraph 7164 Yamax SW-200 Physical activity log
Reliability Value 0.80 0.85 0.90 0.95 0.80 0.85 0.90 0.95 0.80 0.85 0.90 0.95
Total PA 3 4 6 13 4 6 10 21 4 5 8 18
Sedentary Behavior 5 7 11 21 -- -- -- -- -- -- -- --
Light-Intensity PA 3 4 7 14 -- -- -- -- 14 20 21 21
Moderate-Intensity Lifestyle PA 2 3 5 10 -- -- -- -- -- -- -- --
MVPA 2 3 5 10 -- -- -- -- 5 7 12 21
  1. Note. Physical activity (PA); moderate-to vigorous-intensity physical activity (MVPA)
  2. Note. ActiGraph cutpoints used for this analysis were 0-50 counts/min = sedentary behavior; 51-759 counts/min = light intensity physical activity; 760-1951 = moderate lifestyle physical activity; ≥1952 = moderate-to-vigorous physical activity (Crouter et al., 2006; Matthews, 2005; Freedson et al., 1998). For the PA log, Light PA = activities ranging from 1-2.99 METs and MVPA = activities ≥3 METs (Pate et al., 1995).
  3. Note. Physical activity log light intensity physical activity is inclusive of sedentary behavior