This study aimed to compare the adolescents’ body dissatisfaction with physical activity, teasing during physical activity and social support. Participants were 938 Brazilian adolescents aged 15–19 years. Study variables were investigated through questionnaires. There was no difference in body dissatisfaction among adolescents who practiced and did not practice physical activity, but among the former, those who had been teased had greater body dissatisfaction. Also, adolescents who had a relative or friend to talk, in addition to giving and receiving affection, more frequently, presented lower body dissatisfaction. Stratifying the sample by gender, the results were similar in females but were not significant in males.

Objective To assess secular trends in body image dissatisfaction and associated factors among adolescents over a 10-year period (2007-2017/2018). Methods The sample included 1,479 (2007, n = 531; 2017/2018, n = 948) high school adolescents of both sexes, aged 14 to 18 years, of schools in a city in southern Brazil, in 2007 and 2017/2018. Data were collected on sex, age, physical activity (IPAQ, short form), anthropometric measurements (body weight, height, and triceps and subscapular skinfolds), and body image dissatisfaction (figure rating scale). The variables were compared with Independent samples t-test and Mann–Whitney U-test. The associations between sex and other variables were examined with chi-square test, and the factors associated with body image were identified with multinomial logistic regression. Results Most adolescents were dissatisfied with their body image in 2007 (65,2%) and 2017/2018 (71,1%). The prevalence of body dissatisfaction increased by 9.2% over the 10-year period, particularly dissatisfaction with thinness (21.3%). After stratification by sex, in 2017/2018 sample, dissatisfaction with overweight was 46.1% greater in boys, and dissatisfaction with thinness was 66.9% greater in girls. Factors found to be significantly associated with body image dissatisfaction were physical activity level, and body adiposity. Conclusions There was a secular trend toward increased body image dissatisfaction in both sexes. Future efforts should go beyond scientific production, in public and private environments aimed at increasing awareness of health issues related to body care in the physical, psychological, and environmental domains.

Adolescence is a period characterized by large accumulation of bone mass. Body composition is an important determinant of bone mass. This study aimed to assess the relationship of bone mass with lean mass (LM) and fat mass (FM) in normal-weight and overweight adolescents with consideration of sex, sexual maturation and physical activity covariates. A total of 118 adolescents (60 girls and 58 boys) aged between 10 and 14 years participated in the study. Individuals were classified as normal weight or overweight according to body mass index. Bone mineral density (BMD), bone mineral content (BMC), LM, and FM were measured by dual-energy X-ray absorptiometry. In normal-weight adolescents, LM (β = 0.725, p < 0.001) and FM (β = 0.185, p = 0.019) were associated with lumbar spine BMC, whereas in overweight adolescents only LM (β = 0.736, p < 0.001) was associated with lumbar spine BMC. Furthermore, in the normal-weight group, FM and LM were associated with total body less head BMD (LM, β = 0.792, p < 0.001; FM, β = 0.257, p = 0.007) and lumbar spine BMD (LM, β = 0.553, p < 0.001; FM, β = 0.199, p < 0.035). In the overweight group, only LM was associated with total body less head BMD (β = 0.682, p < 0.001) and lumbar spine BMD (β = 0.528, p < 0.001). LM was the main predictor of bone mass in normal-weight and overweight adolescents. FM was associated with bone mass in normal-weight adolescents only. LM may be considered an important and useful marker in adolescents, when investigating bone health in this population. Activities that promote LM gain to reduce the risk of bone fractures and diseases in adulthood are recommended.

Objective: Assess the agreement and validity between relative body fat percentages estimated using anthropometric measurements and air displacement plethysmography (ADP). Methods: A cross-sectional study was conducted on 118 adolescents (60 females) aged 10 to 14 years (x̄=12.19, sd=1.18). Adolescents were classified as eutrophic or with overweight according to body mass index (body weight/height2) (x̄=20,12, sd=3,56). Measurements of skinfold thickness (triceps and medial calf) were collected and used to estimate relative body fat by the Slaughter equation. ADP was used as a reference method for the estimation of relative body fat. Agreement between body fat measurement methods (anthropometry × ADP) was analyzed by the Bland–Altman method. The mean error (ME) was calculated by subtracting the body fat percentage estimated by the Slaughter equation from the body fat percentage estimated by ADP. Validity was tested with the concordance correlation coefficient (CCC). Results: There was no agreement between the methods, regardless of sex and weight status. For boys with overweight (ME = 4.52; p = 0.007), eutrophic girls (ME = 6.37; p < 0.001), and girls with overweight (ME = 5.55; p < 0.001), the Slaughter equation resulted in overestimation of body fat compared with ADP. Skinfold equations did not demonstrate validity when compared with ADP. Conclusion: Slaughter's skinfold equations did not demonstrate agreement and validity compared with ADP in either sex or weight status. Skinfold equations should be used with caution and, whenever possible, in combination with other body composition indicators.

Objetivo: Identificar as associações entre aptidão física, atividade física extracurricular e adiposidade corporal em uma amostra representativa de adolescentes de Florianópolis, Brasil. Método: estudo transversal, de base escolar, que incluiu 981 adolescentes de 14 a 18 anos, matriculados em escolas públicas do município de Florianópolis-SC. A variável dependente foi a adiposidade corporal, obtida pela soma de duas dobras cutâneas (tríceps + subescapular). A participação em atividades físicas extracurriculares e os componentes relacionados à saúde da aptidão física (flexibilidade, força e resistência muscular, aptidão cardiorrespiratória) foram considerados variáveis ​​independentes. Resultados: A prevalência de alta adiposidade corporal foi de 27,1%, sem diferença entre os sexos (meninos=25%, meninas=29,4%). Houve associação negativa entre adiposidade corporal, aptidão cardiorrespiratória e resistência abdominal em ambos os sexos. O modelo final explicou 58,2% da variação nos altos escores de adiposidade corporal em meninas e 47,9% em meninos. Em ambos os sexos, foram encontradas associações negativas entre aptidão cardiorrespiratória (meninas: β = -0,752, p= <0,001; meninos: β = -0,655, p< 0,001) e resistência abdominal (meninas: β = -0,070, p = 0,021; crianças: β = -0,077, p= 0,021) com adiposidade corporal. Além disso, nas meninas, foram observadas associações negativas entre atividade física extracurricular (β = -0,078, p= 0,010) e nos meninos força de preensão (β = -0,121, p< 0,001) e flexibilidade (β = -0,082, p = 0,015) com adiposidade corporal. Conclusão: Em ambos os sexos, maiores níveis de aptidão cardiorrespiratória e resistência abdominal estiveram associados a menor adiposidade corporal. Nas meninas, a atividade extracurricular e nos meninos, a força muscular e a flexibilidade associaram-se negativamente com a adiposidade corporal. Palavras-chave: Adolescente. Composição do corpo. Atividade física extracurricular. Cinantropometria.

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