Table 2.

The relationship between sedentary behaviour and motor development

No. of participants (No. of studies)	Design	Quality assessment					Absolute effect	Quality
		Risk of bias	Inconsistency	Indirectness	Imprecision	Other
Participant ages at time of exposure measurement ranged from ~4 mo (0.3 yr) to 3–4 years; the oldest mean age at follow-up was 5.4 years. Data were collected cross-sectionally and up to 3 years of follow-up. Motor development indicators were assessed by parent-report unless otherwise indicated; specific indicators were: age at first sitting, age at first crawling, age at first walking, locomotion/locomotor skills (assessed by a “test of gross motor development” or CHAMPS Motor Skill Protocol), motor skill development (assessed by the PDMS-2 or CHAMPS Motor Skill Protocol), motor skills (assessed by a “neurological optimality score”), object control (assessed by a “test of gross motor development”, or CHAMPS Motor Skill Protocol), and visual-motor abilities (assessed by the WRAVMA test).
3413 (3)	Longitudinala	Serious risk of biasb	No serious inconsistency	No serious indirectness	No serious imprecision	None	Screen-based sedentary behaviours: TV time (duration): 2/3 studies reported null associations [88, 91] 1/3 studies reported mixed unfavourable and null associations [92] Other sedentary behaviours: Time in a baby carrier/sling (duration): 1/1 studies reported null associations [91] Time in a car seat (duration): 1/1 studies reported mixed null and favourable associations [91] Time in a high chair or other chair (duration): 1/1 studies reported null associations [91] Time in a playpen (duration): 1/1 studies reported null associations [91] Time in a stroller (duration): 1/1 studies reported null associations [91]	Very lowc
681 (4)	Cross-sectionald	Serious risk of biase	No serious inconsistency	No serious indirectness	No serious imprecision	None	Objectively measured sedentary time: Sedentary time 30-min bouts (accelerometer-derived): 1/1 studies reported null associations [40] Total sedentary time (accelerometer-derived): 1/2 studies reported null associations [40] 1/2 studies reported mixed unfavourable and null associations [37] Screen-based sedentary behaviours: TV time (duration): 1/1 studies reported unfavourable associations [94] Other sedentary behaviours: Time in supine position (duration): 1/1 studies reported mixed unfavourable and null associations [93]	Very lowf

CHAMPS Children’s Activity and Movement in Preschool Study, PDMS-2 Peabody Developmental Motor Scales–second edition, WRAVMA Wide-Range Assessment of Visual Motor Ability

^aIncludes 3 longitudinal studies [88, 91, 92] from 3 unique samples

^bSerious risk of bias. Questionable validity and reliability of exposure measure [88, 91, 92]

^cThe quality of evidence from longitudinal studies was downgraded from “low” to “very low” because of a serious risk of bias that diminished the level of confidence in the observed effects

^dIncludes 4 cross-sectional studies [37, 40, 93, 94] from 4 unique samples

^eSerious risk of bias. Questionable validity and reliability of exposure measure [93, 94]; large amount (30.9%) of unexplained missing data and pattern of nonresponse indicates reason for missing data may have been related to the outcome of interest [40]; sleep during the day was included in sedentary time exposure [40]

^fThe quality of evidence from cross-sectional studies was downgraded from “low” to “very low” because of a serious risk of bias that diminished the level of confidence in the observed effects