1. Introduction
SB, Sedentary behavior
SECONDARY, DISEASES
Sedentary behavior (SB) is a risk factor for chronic non-communicable diseases. This study aimed to assess the effects of an extracurricular physical exercise program and health advice on SB in adolescents. This was a non-randomized experimental study involving 19 adolescents divided into an intervention group (IG) and a control group (CG), aged 13–16 years from a public school in a Brazilian municipality. SB was measured using self-reports and accelerometers. The intervention included physical exercise and health advice. Repeated measures analysis of variance with a significance level of α = 5% was used. There was a time*group interaction for the subscapular fold ((pre IG = 16.30 mm vs. CG = 13.44 mm, post IG = 14.00 mm vs. CG = 15.89 mm) Sedentary behavior (SB) is defined as any type of behavior held by an individual while awake in a sitting, lying, or reclining position which promotes an energy expenditure of ≤1.5 metabolic equivalents (METs) [Adolescence is the transition from childhood to adulthood [There is a large amount of evidence demonstrating an association between SB and negative health outcomes in adolescence. A meta-analysis by Hermoso et al. [These and other harms make SB an important risk factor for chronic non-communicable diseases [Despite the significant damage to health caused by SB, most experimental studies have focused on other outcomes (food and physical activity), with SB as a secondary outcome [Therefore, it is necessary to carry out interventions that aim to reduce SB in adolescents and that use a combination of instruments of direct and indirect measures to obtain more reliable data. Accordingly, the aim of this study was to assess the effects of an extracurricular physical exercise program and health advice on SB in adolescents, as well as determining the effects of this intervention on anthropometric measures, body composition, cardiorespiratory fitness, blood pressure, and biochemical markers.