title: Effects of strength training on body composition and bone mineral content in children who are obese.
abstract: The purpose of this study was to test the hypothesis that strength training benefits diet-controlled obese children with respect to lean mass and bone mineral acquisition. Eighty-two Hong Kong school children (aged 10.4 +/- 1.0 years, 70 in Tanner stage 1, 12 in stage 2) who were obese/overweight were randomly assigned to receive either a balanced low-energy (900-1200 cal) diet plus strength training (n = 41) (training group) or the diet alone (n = 41) (control group). The training group attended a 75-minute strength exercise program 3 times/week for 6 weeks (phase 1), after which they were offered and 22 children opted to continue a once-weekly program for a further 28 weeks (phase 2). All children were evaluated at baseline, after 6 weeks, and at the end of the 36-week study (including an intervening 2-week introduction to phase 2). Body composition and bone mineral content were measured by dual-energy X-ray absorptiometry, and diet was assessed by food-frequency questionnaire. The results showed that the exercise programs were well accepted, with good attendance at the exercise classes. After 6 weeks, the children in the training group showed significantly larger increases in lean body mass (+ 0.8 kg [2.4%] vs. +0.3 kg [1.0%], p < 0.05) and total bone mineral content (+46.9 g [3.9%] vs. +33.6 g [2.9%], p < 0.05) than those in the control group. At the end of the study, these trends were maintained in the continued-training subgroup, though no longer reaching statistical significance. We conclude that in diet-controlled prepubertal obese/overweight children, participation in an exercise program with emphasis on strength training resulted in improved lean mass and bone mineral accrual.
authors.affiliation: Department of Paediatrics, Prince of Wales Hospital, The Chinese University of Hong Kong.
authors.forename: Clare C W
authors.initials: CC
authors.lastname: Yu
authors.forename: Rita Y T
authors.initials: RY
authors.lastname: Sung
authors.forename: Raymond C H
authors.initials: RC
authors.lastname: So
authors.forename: Kam-Chi
authors.initials: KC
authors.lastname: Lui
authors.forename: Winnie
authors.initials: W
authors.lastname: Lau
authors.forename: Peggo K W
authors.initials: PK
authors.lastname: Lam
authors.forename: Edith M C
authors.initials: EM
authors.lastname: Lau
mesh_terms: D015502:Absorptiometry, Photon; D001823:Body Composition / Q000502:physiology*; D015519:Bone Density; D002648:Child; D004038:Diet, Reducing; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006723:Hong Kong; D006801:Humans; D008297:Male; D009765:Obesity / Q000503:physiopathology* / Q000517:prevention & control*; D016896:Treatment Outcome