Table 1.

Four ways to define intensity thresholds for the ROC curve analysis.

Intensity	Methods for defining intensity thresholds
Based on MET values from each activity (where 1 MET = 3.5 mL/kg/min)	Based on MET values from each activity (where 1 MET = 3.0 mL/kg/min)	Based on Ratings of Perceived Exertion	Based on Specific Activities
Sedentary	≤ 1.5	≤ 1.5	6, 7 (easy), or 8	DVD, puzzle
Light low	1.6–2.2	1.6–2.2	9 (very light) or 10	Wash/dry dishes
Light high	2.3–2.9	2.3–2.9	11 (fairly light)	Laundry, mopping, treadmill 1.5 mpha
Moderate to vigorous	≥ 3.0	≥ 3.0	≥ 12	400 m walk, treadmill 2.0 mpha, treadmill 2.5 mpha

MET = metabolic equivalent; mL/kg/min: milliliters of oxygen per kilogram per minute; ROC = receiver operating characteristic.

^aNote: All four methods were calculated with and without treadmill walking. Final results presented in the paper excluded treadmill walking (Table 3, Table 4). The moderate to vigorous physical activity analyses were also conducted using only the 400 m walk (Table A.3).