Table 2.

Bone Mineral Density by Sport-Specialization Status in High School Female Distance Runners

Characteristic	Sport-Specialization Status, Mean ± SD				P Value
	Total (N = 64)	Lowa (n = 26)	Moderateb (n = 24)	Highc (n = 14)
Bone mineral density, g/cm2
Spine (L1–L4)	1.107 ± 0.104	1.144 ± 0.106	1.086 ± 0.856	1.072 ± 0.115	.04d
Total hip	1.088 ± 0.109	1.121 ± 0.916	1.061 ± 0.137	1.074 ± 0.072	.19d
Femoral neck	1.108 ± 0.102	1.152 ± 0.085e	1.074 ± 0.113e	1.100 ± 0.853	.08d
Whole body	1.133 ± 0.073	1.149 ± 0.075	1.128 ± 0.075	1.114 ± 0.065	.35d
z score
Spine	−0.4 ± 1.1	0.0 ± 1.0	−0.7 ± 0.9	−0.7 ± 1.4	.06f
Whole body	0.3 ± 0.9	0.6 ± 0.9	0.2 ± 0.9	0.2 ± 0.9	.32f

^aLow: Distance running (cross-country [XC], track and field [TF], both) ≤8 mo/y competitive sport participation or training and 1 or more other sport(s) played.

^bModerate: Distance running (XC, TF, both) only ≤8 mo/y competitive sport participation or training or distance running (XC, TF, both) ≥9 mo/y competitive sport participation or training and 1 or more other sport(s) played.

^cHigh: Distance running only (XC, TF, both) for ≥9 mo/y competitive sport participation or training.

^dAnalysis of covariance adjusted for chronological age, body mass index, and gynecological age.

^eP = .03 with Bonferroni correction compared with high sport specialization.

^fAnalysis of covariance adjusted for body mass index and gynecological age.