title: Habitual site-specific upper extremity loading is associated with increased bone mineral of the ultradistal radius in young women.
abstract: BACKGROUND
  Osteoporosis and osteopenia are major contributors to the high incidence of fractures in older women. Habitual loading plays a crucial role in the acquisition and maintenance of bone. It may be possible to develop clinical interventions based on targeted modes of physical loading that can improve bone health and reduce fractures in women. If so, an important first step is determining the degree to which common fracture sites, such as the distal radius are responsive to habitual loading.
  
  
  METHODS
  The bone mineral density (BMD) and bone mineral content (BMC) of the ultradistal radius of 15 female gymnasts were compared with those of an age-matched, mass-matched, and height-matched control group. The hypothesis that the ultradistal radius BMD and BMC in gymnasts would be higher than those of the control group was tested using a 2 x 2 (left/right x group) repeated measures analysis of variance (MANOVA).
  
  
  RESULTS
  After adjusting for the between-group difference in the influence of body mass, the gymnasts had 24% larger BMD and a 34% larger BMC at the ultradistal radii than the control group (p < 0.001).
  
  
  CONCLUSIONS
  These results suggest that the ultradistal radius is responsive to the types and magnitudes of load encountered during gymnastics. A responsive distal radius is a necessary prerequisite to the development of loading-based interventions to increase ultradistal radius bone quality. Such interventions have the potential to significantly increase distal radius strength, thereby reducing the incidence of fracture.
authors.affiliation: Musculoskeletal Biomechanics Laboratory, Department of Kinesiology and Nutrition, University of Illinois at Chicago, Illinois 60612, USA.
authors.forename: Mary Lou
authors.initials: ML
authors.lastname: Bareither
authors.forename: Mark D
authors.initials: MD
authors.lastname: Grabiner
authors.forename: Karen L
authors.initials: KL
authors.lastname: Troy
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D015519:Bone Density; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D006173:Gymnastics; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D015999:Multivariate Analysis; D005082:Physical Exertion / Q000502:physiology*; D011884:Radius / Q000502:physiology*; D034941:Upper Extremity / Q000502:physiology*; D055815:Young Adult