1 Accelerometry assessed sedentary behaviour and physical activity levels during the segmented school day 1 in 10 - 14 year - old children : the HAPPY study 2 3 Daniel

Accelerometry assessed sedentary behaviour and physical activity levels during the segmented school day 1 in 10-14 year-old children: the HAPPY study 2 3 Daniel P Bailey Stuart J Fairclough, Louise A Savory, Sarah J Denton, Dong Pang, Colleen S Deane, 4 Catherine J Kerr 5 6 Corresponding author: Daniel P Bailey. Email: [email protected]. Telephone: +441234 793268 7 8 Abstract 9 The school day offers several different time periods that provide varying opportunities for sedentary time (SED) 10 and engagement in physical activity (PA), yet little is known about the PA and sedentary behaviour patterns of 11 boys and girls during these times. The volume, intensity and temporal distribution of SED and PA undertaken 12 by 135 schoolchildren aged 10-14 years, during different segments of the school day: a) school transport, b) 13 morning recess, c) lunch break, d) class time, and e) after school, was explored using tri-axial accelerometry. PA 14 was categorised into SED, light PA (LPA), moderate PA (MPA), and vigorous PA (VPA). Girls engaged in 15 significantly more SED and LPA than boys during recess and lunch break (p < 0.05), while boys engaged in 16 significantly higher levels of VPA during recess (p < 0.001) and MPA and VPA during lunch break (p < 0.001). 17 PA engagement was similar between sexes during other segments of the day. Conclusion PA patterns appear 18 more beneficial for health in boys during less structured school-based time periods and interventions may 19 therefore target opportunities for girls to be physically active during these times to overcome this observed sex 20 deficit. 21 22