title: Regional bone mineral density in male athletes: a comparison of soccer players, runners and controls.
abstract: OBJECTIVE
  To investigate the association of soccer playing and long-distance running with total and regional bone mineral density (BMD).
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Academic medical centre.
  
  
  METHODS
  Elite male soccer players (n = 15), elite male long-distance runners (n = 15) and sedentary male controls (n = 15) aged 20-30 years.
  
  
  METHODS
  BMD (g/cm2) of the lumbar spine (L1-L4), right hip, right leg and total body were assessed by dual-energy x-ray absorptiometry, and a scan of the right calcaneus was performed with a peripheral instantaneous x-ray imaging bone densitometer.
  
  
  RESULTS
  After adjustment for age, weight and percentage body fat, soccer players had significantly higher whole body, spine, right hip, right leg and calcaneal BMD than controls (p = 0.008, p = 0.041, p<0.001, p = 0.019, p<0.001, respectively) and significantly higher right hip and spine BMD than runners (p = 0.012 and p = 0.009, respectively). Runners had higher calcaneal BMD than controls (p = 0.002). Forty percent of the runners had T-scores of the lumbar spine between -1 and -2.5. Controls were similar: 34% had T-scores below -1 (including 7% with T-scores lower than -2.5).
  
  
  CONCLUSIONS
  Playing soccer is associated with higher BMD of the skeleton at all sites measured. Running is associated with higher BMD at directly loaded sites (the calcaneus) but not at relatively unloaded sites (the spine). Specific loading conditions, seen in ball sports or in running, play a pivotal role in skeletal adaptation. The importance of including an appropriate control group in clinical studies is underlined.
authors.affiliation: Department of Orthopaedic Surgery, Division of Sports Medicine, Stanford University, 300 Pasteur Drive, Stanford, California 94306, USA. mfred2@stanford.edu
authors.forename: Michael
authors.initials: M
authors.lastname: Fredericson
authors.forename: Kelvin
authors.initials: K
authors.lastname: Chew
authors.forename: Jessica
authors.initials: J
authors.lastname: Ngo
authors.forename: Tammy
authors.initials: T
authors.lastname: Cleek
authors.forename: Jenny
authors.initials: J
authors.lastname: Kiratli
authors.forename: Kristin
authors.initials: K
authors.lastname: Cobb
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology*; D003430:Cross-Sectional Studies; D006801:Humans; D008297:Male; D012420:Running / Q000502:physiology*; D012916:Soccer / Q000502:physiology*