Table 1.

Accelerometer Outcome Variables for Physical Activity and Sleep/Rest^a

	Outcome	Unit	Abbreviation	Interpretation
	Physical activity
1	Average acceleration over the 24-hour day	mg	Overall physical activity	Proxy for total physical activity
2	Moderate-to-vigorous physical activity in 1-min boutsb	min	MVPA	Purposeful activity (e.g. walking) accumulated in 1-min bouts
	Activity and sleep/rest
3	Average acceleration over most active continuous 16 h	mg	Activity during waking hours	Overall intensity of movement during the most active 16 h of the day as a proxy for waking hours. Greater values present a higher level of physical activity within this window.
4	Average acceleration over least active continuous 8 hc	mg	Movement during sleep/rest	Overall intensity of movement during the least active 8 h of the day sleep/rest as a proxy for the sleep window (main rest period). Lower values represent a more restful window of recovery.
5	The intensity of the most active 16 h expressed as % of average acceleration over the 24-h day	%	Balance between activity and sleep/rest	A proxy for the balance between activity and rest/sleep in a 24-h day. A value of 100% would mean no distinction between activity and sleep/rest (ie, no drop in movement levels during the main sleep/rest period). As the value gets closer to 150% it indicates an increasingly distinct activity/rest cycle with two thirds of the day active and one third resting.
	Variability in timing of activity and sleep/rest
6	Variability (SD) in the start time of the most active continuous 16 h	min	Variability in timing of activity	Proxy for variability in time of sleep offset (wake)
7	Variability (SD) in the start time of the least active continuous 8 hb	min	Variability in timing of sleep/rest	Proxy for variability in time of sleep onset
8	Variability (SD) in the midpoint of the time difference between the start of the most active continuous 16 h and least active continuous 8 hc	min	Variability in sleep/rest midpoint	Proxy for variability in mid-sleep time

^aMVPA = moderate-to-vigorous physical activity.

^bAccelerometer cut-point for classification of MVPA = 100 mg.¹⁰

^cTo allow for differences in the duration of sleep, we conducted sensitivity analyses assessing the effects of the average acceleration and timing of the least active 6 h rather than 8 h.