Trajectories of Objectively Measured Physical Activity among Secondary Students in Canada in the Context of a Province-Wide Physical Education Policy: A Longitudinal Analysis
Table 2
Objectively measured physical activity at baseline and follow-up periods across grade cohorts and total study sample.
Grade 9 ()
Grade 10 ()
Total ()
value
%
%
%
Students with valid PA at each time point
T0: Prepolicy
296
(100.0)
151
(100.0)
477
(100.0)
N.A.
T1: February 2009–June 2009
99
(33.4)
68
(45.0)
167
(37.4)
N.A.
T2: September 2009–January 2010
73
(24.7)
21
(13.9)
94
(21.0)
N.A.
T3: February 2010–June 2010
138
(46.6)
94
(62.3)
232
(51.9)
N.A.
T4: September 2010–January 2011
54
(18.2)
0
(0.0)
54
(12.1)
N.A.
T5: February 2011–June 2011
122
(41.2)
2
(0.0)
124
(27.7)
N.A.
T6: September 2011–December 2011
44
(14.9)
0
(0.0)
44
(0.09)
N.A.
Time points contributed per student, mean ± SD
2.79
±1.18
2.23
±0.850
2.60
±1.11
<0.0001a
Baseline PA
Students with baseline data
296
(100.0)
151
(100.0)
447
(100.0)
N.A.
Minutes per day, mean ± SD
58.7
±24.1
57.6
±23.8
58.3
±24.0
0.5890a
Accumulated ≥ 30 min/day
265
(89.5)
131
(86.8)
396
(88.6)
0.3833b
Accumulated ≥ 60 min/day
138
(46.6)
61
(40.4)
199
(44.5)
0.2104b
PA at students’ last followup
Students with ≥ 1 followup
230
(77.7)
110
(72.9)
340
(76.1)
0.3304b
Minutes per day, mean ± SD
42.6
±23.5
47.2
±23.9
44.1
±23.7
0.0485a
Accumulated ≥ 30 min/day (% with ≥ 1 followup)
149
(64.8)
82
(74.6)
231
(67.9)
0.0712b
Accumulated ≥ 60 min/day (% with ≥ 1 followup)
46
(20.0)
25
(22.7)
71
(20.9)
0.5627b
PA change from baseline to last followup
Students with ≥ 1 followup
230
(77.7)
110
(72.9)
340
(76.1)
0.3304b
Change (min/day), mean ± SD
−14.6
±24.7
−11.1
±29.0
−13.4
±26.2
0.2701a
Percentage change (%), mean ± SD
−18.7
±48.8
−10.0
±51.0
−15.9
±49.6
0.1871a
Wilcoxon two-sample test used to compare across grade cohorts.
bChi-square test used to compare across grade cohorts. N.A.: denotes not applicable.
