TABLE 3—

Self-Reported Physical Activity and Sedentary Behaviors at Baseline and Annual Follow-Up Among School Children in 2 Communities: Project Healthy Schools, Michigan, 2005–2010

	First Follow-Up, Mean		Second Follow-Up, Mean		Third Follow-Up, Mean		Fourth Follow-Up, Mean
Variable	Baseline	Follow-Up	Baseline	Follow-Up	Baseline	Follow-Up	Baseline	Follow-Up
Ann Arbor schools
Sample size	740	672	739	739	263	263	252	252
Physical Activities
20-min vigorous physical activity, sessions/wk	4.61	4.95***	4.61	4.76	4.54	4.85	4.48	4.65
30-min moderate physical activity, sessions/wk	3.49	3.94***	3.47	4.08***	3.48	4.22***	3.5	3.72
School sports team, no. of teams	1.15	1.61***	1.13	1.32***	1.25	1.45*	1.23	1.20
Sedentary activities
TV time, h/d	1.56	1.52	1.59	1.55	1.43	1.47	1.43	1.34
Computer time, h/d	1.07	1.13	1.06	1.29***	0.95	1.36***	0.93	1.32***
Video games time, h/d	0.80	0.70**	0.80	0.67**	0.67	0.54**	0.66	0.52*
Ypsilanti schools
Sample size	230	225	223	223	143	143	50	50
Physical Activities
20 min vigorous physical activity, sessions/wk	3.99	4.29	3.94	4.04	3.97	3.63	3.92	3.56
30 min moderate physical activity, sessions/wk	3.25	3.60	3.22	3.22	3.21	3.26	3.38	2.88
School sports team, no. of teams	0.57	0.65	0.58	1.02***	0.56	0.85**	0.56	1.04**
Sedentary activities
TV time, h/d	2.71	2.42*	2.7	2.57	2.82	2.33***	3.15	2.34**
Computer time, h/d	1.35	1.38	1.35	1.53	1.45	1.60	1.65	1.56
Video games time, h/d	1.43	1.45	1.43	1.19*	1.33	1.07*	1.72	1.20*

Note. P values indicate that there is a significant difference between a follow-up and the baseline. Each comparison included only those students who were available at the time of follow-up.

*P ≤ .05; **P ≤ .01; ***P ≤ .001.