Table 2.

Comparison of characteristics of children from the intervention group and control group at baseline.

	Total Sample (n = 2066)	Control (n = 503)	Intervention (n = 1563)
Age (years), mean ± SD	9.0 ± 1.04	9.2 ± 1.11	8.9 ± 1.01
Gender, n (%)
Male	1077 (52.1)	268 (53.3)	809 (48.2)
Female	989 (47.9)	235 (46.7)	754 (51.8)
Grade, n (%)
Two	682 (33.0)	180 (35.8)	502 (32.1)
Three	662 (32.0)	139 (27.6)	523 (33.5)
Four	722 (35.0)	184 (36.6)	538 (34.4)
County, n (%)
Zigui County	837 (40.5)	172 (34.2)	665 (42.6)
Du‘an County	875 (42.4)	240 (47.7)	635 (40.6)
Long‘an county	354 (17.1)	91 (18.1)	263 (16.8)
Physical activity, n (%)
0–30 min/d	603 (29.2)	196 (39.0)	407 (26.0)
30–60 min/d	722 (35.0)	146 (29.0)	576 (36.9)
≥60 min/d	741 (35.9)	161 (32.0)	580 (37.1)