title: Weight-bearing exercise and markers of bone turnover in female athletes.
abstract: Weight-bearing activity provides an osteogenic stimulus, while effects of swimming on bone are unclear. We evaluated bone mineral density (BMD) and markers of bone turnover in female athletes (n = 41, age 20.7 yr) comparing three impact groups, high impact (High, basketball and volleyball, n = 14), medium impact (Med, soccer and track, n = 13), and nonimpact (Non, swimming, n = 7), with sedentary age-matched controls (Con, n = 7). BMD was assessed by dual-energy X-ray absorptiometry at the lumbar spine, femoral neck (FN), Ward's triangle, and trochanter (TR); bone resorption estimated from urinary cross-linked N-telopeptides (NTx); and bone formation determined from serum osteocalcin. Adjusted BMD (g/cm; covariates: body mass index, weight, and calcium and calorie intake) was greater at the FN and TR in the High group (1.27 +/- 0.03 and 1.05 +/- 0.03) than in the Non (1.05 +/- 0.04 and 0.86 +/- 0.04) and Con (1.03 +/- 0.05 and 0.85 +/- 0.05) groups and greater at the TR in the Med group (1.01 +/- 0.03) than in the Non (0.86 +/- 0.04) and Con (0.85 +/- 0.05) groups. Total body BMD was higher in the High group (4.9 +/- 0.12) than in the Med (4.5 +/- 0.12), Non (4.2 +/- 0.14), and Con (4.1 +/- 0.17) groups and greater in the Med group than in the Non and Con groups. Bone formation was lower in the Non group (19.8 +/- 2.6) than in the High (30.6 +/- 3.0) and Med (32.9 +/- 1.9, P < or = 0.05) groups. No differences in a marker of bone resorption (NTx) were noted. This indicates that women who participate in impact sports such as volleyball and basketball had higher BMDs and bone formation values than female swimmers.
authors.affiliation: Department of Kinesiology, College of Health and Human Services, University of Toledo, Toledo, Ohio 43606, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Creighton
authors.forename: A L
authors.initials: AL
authors.lastname: Morgan
authors.forename: D
authors.initials: D
authors.lastname: Boardley
authors.forename: P G
authors.initials: PG
authors.lastname: Brolinson
mesh_terms: D000328:Adult; D001490:Basketball / Q000502:physiology; D015415:Biomarkers / Q000032:analysis*; D015519:Bone Density; D016723:Bone Remodeling; D003094:Collagen / Q000652:urine; D024042:Collagen Type I; D005260:Female; D006801:Humans; D015675:Osteocalcin / Q000097:blood; D010455:Peptides / Q000652:urine; D012916:Soccer / Q000502:physiology; D013177:Sports / Q000502:physiology*; D013550:Swimming / Q000502:physiology; D014142:Track and Field / Q000502:physiology; D016474:Weight-Bearing
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D003094:Collagen