MVPA activities in Beijing school students by gender and grade.

Abbreviations: MVPA, moderate to vigorous physical activity; IQR = interquartile range, computed for only those reporting any (>0 min). a Descriptive statistics were calculated for total reported time in MVPA (sum of in-school, and outside school). Descriptive statistics herein are therefore presented as the proportion reporting any defined MVPA and the median and interquartile range (IQR) of distribution of time (min/week) for those reporting any of MVPA. a gender difference regardless of grade b grade difference within gender c gender difference within grade. * P<0.05 ** P<0.01 *** P<0.001 MVPA activities in Beijing school students by gender and grade.