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Table 1 Participant Characteristics and Summary Measures of Sedentary Behavior Variables

From: Development of sedentary behavior across childhood and adolescence: longitudinal analysis of the Gateshead Millennium Study

Variable 7y
n = 507 (252 girls, 255 boys)
9y
n = 510 (265 girls, 245 boys)
12y
n = 425 (227 girls, 198 boys)
15y
n = 310 (166 girls, 144 boys)
  mean SD median IQR Mean SD Median IQR mean SD median IQR mean SD median IQR
Age (years) 7.5 0.5 7.4 7.2, 7.8 9.3 0.4 9.3 9.1, 9.6 12.5 0.3 12.5 12.3, 12.7 15.2 0.4 15.2 14.9, 15.5
Wear time (min/d) 670.7 69.1 680.6 632.4, 716.1 672.9 75.5 679.3 630.7, 725.8 717.8 82.4 729.7 663.8, 782.5 725.5 82.6 738.1 682.3, 785.5
Sedentary time (min/d) 346.5 66.6 349.5 302.6, 383.8 373.1 63.5 373.6 329.1, 417.0 467.3 87.3 466.8 409.4, 524.1 535.4 85.4 542.1 478.7, 595.6
Sedentary time (%/d) 51.6 7.7 51.3 46.4, 56.1 55.4 6.9 55.5 50.6, 60.5 64.9 8.3 64.7 59.8, 70.7 73.5 6.6 74.2 69.3, 78.4
Duration break (min) 3.5 0.3 3.4 3.2, 3.6 3.5a 0.3 3.4 a 3.3, 3.7 4.1 3.2 3.7 3.5, 3.9 3.9b 0.4 3.8 b 3.6, 4.2
Breaks per hour > 1 min 8.5 1.3 8.6 7.7, 9.4 7.7 1.2 7.7 6.9, 8.5 5.7 1.6 5.8 4.8, 6.7 4.2 1.1 4.1 3.4, 4.9
Bouts per hour of sedentary time 16.7 1.7 16.9 15.9, 17.8 16.7a 1.6 16.9 a 15.9, 17.8 15.2 2.3 15.5 13.8, 16.8 12.9 2.5 12.9 11.4, 14.6
Bouts lasting 1–4 min 82.8 13.9 83.6 74.1, 92.5 89.2 14.3 90.0 79.3, 98.7 95.2 17.6 95.4 83.5, 106.3 85.7 a 20.8 85.3 a 73.5, 98.3
Bouts lasting 5–9 min 8.2 2.9 8.2 6, 10.3 10.1 3.3 10.0 8, 12.2 14.2 4.3 14.3 11.3, 17.3 16.6 4.1 16.7 14, 19.3
Bouts lasting 10-14 min 1.7 1.0 1.6 1, 2.3 2.3 1.2 2.0 1.4, 3 3.8 1.8 3.8 2.4, 5.0 5.3 1.9 5.3 4, 6.6
Bouts lasting 15-29 min 0.8 0.7 0.6 0.3, 1.1 1.1 0.9 0.9 0.4, 1.4 2.2 1.5 2.1 1.1, 3.0 3.8 2.0 3.7 2.3, 5
Bouts lasting +30 min 0.3 0.7 0.1 0.0, 0.3 0.2 a 0.3 0.0 a 0, 0.3 0.4 0.7 0.3 0.0, 0.6 1.1 1.0 0.9 0.4, 1.5
Sedentary bout length at 50th percentile of sedentary time (min) 3.4 3.8 2.4 1.9, 3.2 3.0 1.8 2.7 2.2, 3.4 4.6 2.9 3.9 3.1, 5.2 7.3 3.9 6.4 4.8, 8.5
  1. Bouts were defined as minimum period of sedentary time without allowing any interruption; SD, standard deviation; IQR, interquartile range
  2. a not different to 7 years; b not different to 12 years