title: Total body fat percentage and body mass index and the association with lower extremity injuries in children: a 2.5-year longitudinal study.
abstract: BACKGROUND
  Overweight youths are generally recognised as being at increased risk of sustaining lower extremity injuries in sports. However, previous studies are inconclusive and choices for measuring overweight are manifold.
  
  
  OBJECTIVE
  To examine two different measures of overweight, body mass index (BMI) and total body fat percentage (TBF%), as risk factors for lower limb injuries in a school-based cohort.
  
  
  METHODS
  A longitudinal cohort study.
  
  
  METHODS
  A total of 632 school children, baseline age 7.7-12.0 years, were investigated. Whole body dual energy x-ray absorptiometry scans provided measures of TBF%. Measures of BMI were obtained by standard anthropometric methods. Musculoskeletal complaints were reported by parents answering weekly mobile phone text messages during 2.5 years. Injuries were diagnosed by clinicians. Leisure time sports participation was reported weekly using text messaging.
  
  
  RESULTS
  During 2.5 years of follow-up, 673 lower extremity injuries were diagnosed. Children being overweight by both BMI and TBF% showed the highest risk of sustaining lower extremity injuries (IRR 1.38 (95% CI 1.05 to 1.81)). Children who were overweight using BMI and TBF% showed the highest risk of sustaining lower extremity injuries (IRR 1.38 (95% CI 1.05 to 1.81)).
  
  
  CONCLUSIONS
  The risk of lower extremity injuries appeared to be increased for overweight children. When comparing two different measures of overweight, overweight by TBF% is a higher risk factor than overweight by BMI. This suggests that a high proportion of adiposity is more predictive of lower extremity injuries, possibly due to a lower proportion of lean muscle mass.
authors.affiliation: Centre for Research in Childhood Health, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
authors.forename: Eva
authors.initials: E
authors.lastname: Jespersen
authors.affiliation: Department of Public and Occupational Health, EMGO+ Institute for Health and Care Research, VU University Medical Centre, Amsterdam, The Netherlands.
authors.forename: Evert
authors.initials: E
authors.lastname: Verhagen
authors.affiliation: Biostatistical Research Unit, Institute of Regional Health Research, University of Southern Denmark, Odense, Denmark.
authors.forename: René
authors.initials: R
authors.lastname: Holst
authors.affiliation: Centre for Research in Childhood Health, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
authors.forename: Heidi
authors.initials: H
authors.lastname: Klakk
authors.affiliation: Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark.
authors.forename: Malene
authors.initials: M
authors.lastname: Heidemann
authors.affiliation: Centre for Research in Childhood Health, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
authors.forename: Christina Trifonov
authors.initials: CT
authors.lastname: Rexen
authors.affiliation: Centre for Research in Childhood Health, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
authors.forename: Claudia
authors.initials: C
authors.lastname: Franz
authors.affiliation: Centre for Research in Childhood Health, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark Department of Orthopaedic, Hospital of Lillebaelt, Institute of Regional Health Service Research and Centre for Research in Childhood Health, IOB, University of Southern Denmark, Odense, Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Wedderkopp
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000473:pathology*; D050154:Adiposity / Q000502:physiology; D015992:Body Mass Index; D002648:Child; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D035002:Lower Extremity / Q000293:injuries*; D008297:Male; D059352:Musculoskeletal Pain / Q000209:etiology; D050177:Overweight / Q000473:pathology*; D010809:Physical Fitness / Q000502:physiology; D012307:Risk Factors; D012737:Sex Factors
keywords: Body composition methodology; Children's injuries; Injury Prevention; Lower extremity injuries