title: High femoral bone mineral density accretion in prepubertal soccer players.
abstract: OBJECTIVE
  To determine the effect of physical activity on bone mineral accrual during growth in prepuberal boys.
  
  
  METHODS
  Seventeen soccer players and 11 matched (physically active) control boys (Tanner 1-2, at the start of the study) were followed over a 3-yr period. Bone mineral content (BMC) and a real density (BMD) was measured by dual-energy x-ray absorptiometry. The maximal positive mechanical impulse (CJipos) and height jumped (Hj) during countermovement vertical jumps were assessed with a plate force. Additionally, 30-m running speed test (T30), 300-m run test (AC), and 20-m shuttle run test (MAP) were performed.
  
  
  RESULTS
  The soccer players attained better results in MAP and AC than the controls (P < 0.05). At the end of the follow-up, the controls increased their percentage of body fat in 11 units (P < 0.05) whereas it remained unchanged in the soccer players. Lean body mass increased with growth but more in the soccer players than in the controls (P < 0.05). The soccer players exhibited greater BMC in the legs and greater BMD in all bone-loaded regions at the end of the study (P < 0.05). During these 3 yr, the soccer players gained twice as much femoral neck and intertrochanteric BMC than the control group (P < 0.05) and increased their femoral neck BMD by 10% and their mean hip BMD by a third more than the control group (both P < 0.05). Multiple regression analysis showed that the improvement in T30 and CJipos has predictive value for the enhancement of bone mass in growing boys.
  
  
  CONCLUSIONS
  Long-term soccer participation, starting at a prepubertal age, results in greater improvement of physical fitness, greater acquisition of bone mass and a lower accumulation of body fat.
authors.affiliation: Department of Physical Education, University of Las Palmas de Gran Canaria, Spain.
authors.forename: German
authors.initials: G
authors.lastname: Vicente-Rodriguez
authors.forename: Ignacio
authors.initials: I
authors.lastname: Ara
authors.forename: Jorge
authors.initials: J
authors.lastname: Perez-Gomez
authors.forename: Jose A
authors.initials: JA
authors.lastname: Serrano-Sanchez
authors.forename: Cecilia
authors.initials: C
authors.lastname: Dorado
authors.forename: Jose A L
authors.initials: JA
authors.lastname: Calbet
mesh_terms: D015502:Absorptiometry, Photon; D015308:Anaerobic Threshold / Q000502:physiology; D001823:Body Composition / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D016022:Case-Control Studies; D002648:Child; D005080:Exercise Test; D005272:Femur Neck / Q000502:physiology; D006615:Hip / Q000502:physiology; D006801:Humans; D008137:Longitudinal Studies; D008159:Lumbar Vertebrae / Q000502:physiology; D008297:Male; D010012:Osteogenesis / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology; D011627:Puberty / Q000502:physiology*; D012044:Regression Analysis; D012420:Running / Q000502:physiology; D012916:Soccer / Q000502:physiology*; D013904:Thoracic Vertebrae / Q000502:physiology