The Relationship between Physical Activity and Bone during Adolescence Differs according to Sex and Biological Maturity

Table 1

Subject characteristics for adolescent boys and girls ($n=99$). Mean (SD).

Characteristics	Boys	Girls	P value
	$n=46$	$n=53$
Age (years)	13.8 (0.4)	13.7 (0.5)	.16
APHV (years)	13.8 (0.7)	12.2 (0.4)	.001
Weight (kg)	55.8 (2.0)	51.0 (1.2)	.04
Standing height (m)	1.65 (0.01)	1.61 (0.01)	.02
Sitting height (m)	0.85 (0.01)	0.84 (0.01)	.33
BMI (kg$·$m^−2)	20.4 (0.6)	19.6 (0.4)	.34
Lean mass (g)	37380 (8390)	30585 (3736)	.001
Fat mass (g)	15983 (8352)	18747 (6239)	.08
% Body fat	22.0 (8.6)	27.7 (5.7)	.002
Vertical jump (cm)	33.6 (1.2)	28.9 (0.9)	.001
Calcium (mg$·$day^−1)	1143 (92)	826 (57)	.004
BPAQ score	3.6 (0.2)	3.1 (0.2)	.052
Television viewing (min$·$day^-1)	153 (97)	120 (86)	.07

Variable definitions: APHV, age of peak height velocity; BMI, body mass index; BPAQ, bone-specific physical activity questionnaire.