title: Relationship between body composition and vertical ground reaction forces in obese children when walking.
abstract: BACKGROUND
  Obesity is now a serious worldwide challenge, especially in children. This condition can cause a number of different health problems, including musculoskeletal disorders, some of which are due to mechanical stress caused by excess body weight. The aim of this study was to determine the association between body composition and the vertical ground reaction force produced during walking in obese children.
  
  
  METHODS
  Sixteen children participated in the study, six females and ten males [11.5 (1.2) years old, 69.8 (15.5) kg, 1.56 (0.09) m, and 28.36 (3.74) kg/m2of body mass index (BMI)]. Total weight, lean mass and fat mass were measured by dual-energy X-ray absorptiometry and vertical forces while walking were obtained by a force platform. The vertical force variables analysed were impact and propulsive forces, and the rate of development of both. Multiple regression models for each vertical force parameter were calculated using the body composition variables as input.
  
  
  RESULTS
  The impact force regression model was found to be positively related to the weight of obese children and negatively related to lean mass. The regression model showed lean mass was positively related to the propulsive rate. Finally, regression models for impact and propulsive force showed a direct relationship with body weight.
  
  
  CONCLUSIONS
  Impact force is positively related to the weight of obese children, but lean mass helps to reduce the impact force in this population. Exercise could help obese persons to reduce their total body weight and increase their lean mass, thus reducing impact forces during sports and other activities.
authors.affiliation: Departamento de Educación Física y Deporte, Universidad de Valencia, Spain.
authors.forename: Israel
authors.initials: I
authors.lastname: Villarrasa-Sapiña
authors.affiliation: Departamento de Fisioterapia, Universidad de Valencia, Valencia, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Serra-Añó
authors.affiliation: Departamento de Educación Física, Universidad Católica de Valencia, Valencia, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Pardo-Ibáñez
authors.affiliation: Departamento de Educación Física y Deporte, Universidad de Valencia, Spain.
authors.forename: Luis-Millán
authors.initials: LM
authors.lastname: Gonzalez
authors.affiliation: Departamento de didáctica de la expresión musical, plástica y corporal, Universidad de Valencia, Valencia, Spain. Electronic address: xavier.garcia@uv.es.
authors.forename: Xavier
authors.initials: X
authors.lastname: García-Massó
mesh_terms: D015502:Absorptiometry, Photon; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D002648:Child; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D063766:Pediatric Obesity / Q000503:physiopathology* / Q000517:prevention & control; D016138:Walking / Q000502:physiology*
keywords: Child obesity; Impact force; Lean mass; Vertical ground reaction forces