title: Muscular strength, aerobic capacity, and adipocytokines in obese youth after resistance training: A pilot study.
abstract: BACKGROUND
  Exercise has shown positive training effects on obesity-related inflammation, however, resistance training has shown mixed results concerning adipocytokine levels.
  
  
  OBJECTIVE
  The purpose of this pilot study was to explore the effects of resistance training on blood adipocytokine concentrations in obese youth, with specific examination of the relationship between these biomarkers and improved fitness (i.e., aerobic capacity, muscular strength).
  
  
  METHODS
  Fourteen obese adolescents (16.1 ±1.6 y; BMI: 32.3 ±3.9 kg/m(2)) participated in a 16-week resistance training intervention. Body composition, fasting blood concentrations of interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-ɑ), adiponectin, and leptin were measured pre- and post-training. Aerobic capacity was assessed via a maximal discontinuous exercise test. The rate of gain in muscular strength was calculated as the slope of progression in 1-repetition maximum throughout the intervention.
  
  
  RESULTS
  Resistance training increased lean mass (total, trunk) and decreased per cent body fat (total, trunk). The training also caused moderate clear decreases in IL-6 and TNF-ɑ concentrations. A small increase in adiponectin was also observed before and after intervention. When the group was stratified by changes in aerobic capacity, there were substantially larger decreases in leptin levels for those with improved capacity. Correlation analyses also revealed a negative relationship between log-transformed leptin and aerobic capacity at rest. Improvement in quadriceps strength was positively correlated with IL-6 and TNF-ɑ, while improvement in shoulder adductor strength was positively correlated with IL-6 only.
  
  
  CONCLUSIONS
  Resistance training improved adipocytokine markers, which were partially associated with improved physical fitness. Specifically, the relationship between strength improvements and IL-6 and TNF-ɑ suggests an exercise-induced signalling pathway that results in overall adaptive decreases in systemic inflammation in obese youth.
authors.affiliation: School of Sport and Exercise, Massey University, Wellington, New Zealand.
authors.forename: Sarah P
authors.initials: SP
authors.lastname: Shultz
authors.affiliation: School of Medicine, University of Queensland, Brisbane, QLD, Australia.
authors.forename: Rachana
authors.initials: R
authors.lastname: Dahiya
authors.affiliation: Department of Paediatric Endocrinology and Diabetes, Mater Children's Hospital, Brisbane, QLD, Australia ; Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, Australia.
authors.forename: Gary M
authors.initials: GM
authors.lastname: Leong
authors.affiliation: School of Sport and Exercise, Massey University, Wellington, New Zealand.
authors.forename: David S
authors.initials: DS
authors.lastname: Rowlands
authors.affiliation: Mater Mothers' Hospital & Mater Research Institute, University of Queensland, Brisbane, QLD, Australia.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Hills
authors.affiliation: Faculty of Health Sciences and Medicine, Bond University, Gold Goast, QLD, Australia.
authors.forename: Nuala M
authors.initials: NM
authors.lastname: Byrne
keywords: Exercise; fitness; inflammation; paediatric obesity