“…[11][12][13] Most of the studies used self-reported questionnaires, but less than half the studies reported information about instrument validity. 9,14,17,18,[30][31][32][33]36,42,[52][53][54][59][60][61][62]65,[67][68][69][70][73][74][75][77][78][79][80][81]86,93,94,97,[99][100][101][102][103][104][105][106] Only three studies assessed sedentary behavior using accelerometers. 11,15,16 The cut-off point used in the studies varied considerably from 2 to 4 hours, although most studies used cut-off point of 2 hours of screen time: 20 studies 18,20,21,27,[30][31][32][33]…”