Effects of 15-minutes physical exercise on physical fitness of adolescents: A protocol study

Overweight, obesity, and low physical fitness (PF) are conditions associated with physical and mental health problems in children and adolescents. Schools and physical education (PE) classes provide ideal environments for promoting physical exercise, improving levels of PF, and preventing obesity in this population. This article outlines the protocol of an experimental study whose primary objective is to assess the effects of a 15-minute physical exercise program implemented during elementary school physical education classes on PF and anthropometric markers of overweight and obesity (AMOO). Enrolled students in 6th to 9th-grade classes within rural elementary schools located in a Southern city in Brazil will participate of the study. The participants will be randomized into the intervention group and control group. The intervention will last for 12 weeks with two sessions per week. Various components of PF and AMOO will be the primary dependent variables. Physical activity level, recreational screen time, sleep duration, physical self-concept, motivation for participating in PE classes, symptoms of anxiety, depression, and stress will be secondary dependent variables. Sociodemographic information and somatic maturation will serve as covariates. All variables will be measured pre and post-intervention. The study’s findings will contribute to a better understanding of the potential of school PE classes to improve PF, AMOO, and, secondarily, health-related behaviors, motivation for participating in PE classes, and the mental health of students. O sobrepeso, a obesidade e a baixa aptidão física (ApF) são condições associadas à problemas de saúde física e mental em crianças e adolescentes. A escola e as aulas de educação física (EF) são ambientes propícios para a promoção do exercício físico e a melhoria dos níveis de ApF e prevenção de obesidade nesta população. Este artigo descreve o protocolo de um estudo experimental que tem como objetivo primário identificar os efeitos de um programa de 15 minutos de exercícios físicos realizados durante as aulas de EF na ApF e em indicadores antropométricos de sobrepeso e obesidade (IASO) de escolares. Participarão do estudo escolares do 6° ao 9° ano de ambos os sexos de escolas da zona rural de uma cidade do sul do Brasil. Os participantes serão randomizados em grupo intervenção e grupo controle. A intervenção terá duração de 12 semanas com duas sessões semanais. Diferentes componentes da ApF e IASO serão variáveis depe