Table 4.

Demographic characteristics, Osgood–Schlatter disease, tibial tuberosity maturity stages, and cartilage thickness at the tibial tuberosity at each examination time point of the longitudinal study in 26 higher elementary grade schoolchildren by sex.

Boys (n = 10)	Base Line a Grade 5 Spring	6 Months b Grade 5 Fall	18 Months c Grade 6 Fall	p-Value #	Multiple Comparisons ##
Demographic characteristics
Age (y)	10.1 ± 0.3	10.5 ± 0.5	11.6 ± 0.5	<0.001	a < b *, a < c **, b < c **
Height (cm)	138 ± 4	140 ± 4	147 ± 5	<0.001	a < b **, a < c **, b < c **
Weight (kg)	32.8 ± 4.9	34.3 ± 5.1	37.8 ± 5.1	<0.001	a < b **, a < c **, b < c **
Appearance of voice change	0	0	0
Sports club affiliation	6 (60)	6 (60)	7 (70)
Osgood–Schlatter disease	0	0	0
Tibial tuberosity maturity stages
Cartilaginous stage	9 (90)	8 (80)	2 (20)
Apophyseal stage	1 (10)	2 (20)	5 (50)
Epiphyseal stage	0	0	3 (30)
Bony stage	0	0	0
Cartilage thickness (mm)	7.8 ± 1.1	8.1 ± 1.8	6.3 ± 2.0	<0.001	a > c **, b > c **
Girls (n = 16)	Base Line a Grade 5 Spring	6 Months b Grade 5 Fall	18 Months c Grade 6 Fall	p-Value #	Multiple Comparisons ##
Demographic characteristics
Age (y)	10.1 ± 0.3	10.5 ± 0.5	11.6 ± 0.5	<0.001	a < b **, a < c **, b < c **
Height (cm)	139 ± 5	142 ± 5	149 ± 4	<0.001	a < b **, a < c **, b < c **
Weight (kg)	32.5 ± 5.5	34.8 ± 5.9	40.7 ± 6.0	<0.001	a < b **, a < c **, b < c **
Appearance of menarche	1 (6)	2 (13)	9 (56)
Sports club affiliation	11 (69)	12 (75)	10 (63)
Osgood–Schlatter disease	0	1 (6)	1 (6)
Tibial tuberosity maturity stages
Cartilaginous stage	2 (13)	0	0
Apophyseal stage	3 (19)	2 (13)	0
Epiphyseal stage	11 (69)	14 (88)	16 (100)
Bony stage	0	0	0
Cartilage thickness (mm)	5.3 ± 1.2	5.4 ± 0.9	4.9 ± 0.7	0.282

Values are means ± standard deviation or numbers of students (%). ^# One-way repeated measures analysis of variance (ANOVA). ^## by Mauchly: ^{a, b, c} ; ** p < 0.01, * p < 0.05.