Effects of Aerobic Versus Resistance Exercise Without Caloric Restriction on Abdominal Fat, Intrahepatic Lipid, and Insulin Sensitivity in Obese Adolescent Boys: A Randomized, Controlled Trial

The optimal exercise modality for reductions of abdominal obesity and risk factors for type 2 diabetes in youth is unknown. We examined the effects of aerobic exercise (AE) versus resistance exercise (RE) without caloric restriction on abdominal adiposity, ectopic fat, and insulin sensitivity and secretion in youth. Forty-five obese adolescent boys were randomly assigned to one of three 3-month interventions: AE, RE, or a nonexercising control. Abdominal fat was assessed by magnetic resonance imaging, and intrahepatic lipid and intramyocellular lipid were assessed by proton magnetic resonance spectroscopy. Insulin sensitivity and secretion were evaluated by a 3-h hyperinsulinemic-euglycemic clamp and a 2-h hyperglycemic clamp. Both AE and RE prevented the significant weight gain that was observed in controls. Compared with controls, significant reductions in total and visceral fat and intrahepatic lipid were observed in both exercise groups. Compared with controls, a significant improvement in insulin sensitivity (27%) was observed in the RE group. Collapsed across groups, changes in visceral fat were associated with changes in intrahepatic lipid (r = 0.72) and insulin sensitivity (r = -0.47). Both AE and RE alone are effective for reducing abdominal fat and intrahepatic lipid in obese adolescent boys. RE but not AE is also associated with significant improvements in insulin sensitivity.

The relevance of sport-related behaviour patterns in the family for the sport participation of youth in Switzerland

Despite various efforts to promote sport participation among youth, social inequalities still exist. An explanation for these social inequalities could be traced back to transgenerational transmission of sport-related values and behaviour patterns in a family (Baur, 1989). Therefore, children’s socialisation to sport is strongly influenced by the parents’ sport-related values and sport behaviour (Burrmann, 2005). However, findings of previous studies are inconsistent, and the daily sport-related behaviour patterns of families have often not been taken into account. The paper deals with the question, to what extent sport participation of youth is influenced by factors such as the importance of sport, the self-evidence of regular sport activity, mutual support, shared sport activities, sport-related health-awareness and communication about sport in the family. In order to pursue this research question, socialisation theories were used as theoretical framework (Hurrelmann, 2006). Based on this approach, a quantitative online survey where 4’039 adolescents and young adults from the ages of 15 to 30 (n = 4’039, M = 21.48, SD = 4.64) answered questions according their sport participation and the sport-related patterns of their families. Furthermore, a qualitative study that included guideline-based interviews with adolescents and young adults (n = 13) were undertaken. Content analysis was used to analyse the interviews. Initial findings of the multiple regression analysis reveal that the most important predictors of sport participation of youth are communication about sport (β = .18, p < .001), mutual support (β = .13, p < .001), regular sport activity (β = .10, p < .01) and the importance of sport in the family (β = .10, p < .01). By means of content analysis, more in-depth information could be identified. The promotion of sport through sport-related behaviour patterns in the family appears to be a successful strategy to develop a durable sport commitment in youth. References Baur, J. (1989). Körper- und Bewegungskarrieren [Body and exercise careers]. Schorndorf: Hofmann. Burrmann, U. (2005). Zur Vermittlung und intergenerationalen "Vererbung" von Sport(vereins)engagements in der Herkunftsfamilie [On placing and "inheriting" intergenerational sport(club) commitment in the family of origin]. Sport und Gesellschaft, 2, 125–154. Hurrelmann, K. (2006). Einführung in die Sozialisationstheorie [Introduction to socialisation theory] (9th ed.). Studium Paedagogik. Weinheim: Beltz.