Frederico Bento de Moraes Junior

This study aims to verify the effect of social isolation arising from the Coronavirus pandemic (COVID-19) severe acute respiratory syndrome (SARS-CoV-2) on vitamin D (25(OH)D) concentrations, motor performance, and cardiorespiratory fitness (CRF) in adolescents. This research method is Case-control study, which included 34 boys, aged 12-16 years. In the pre-pandemic period, 17 schoolchildren were evaluated in December 2019, classified according to body mass index Z-score (BMI-z) as: eutrophic (n=8) and overweight (n=9). The post-pandemic group was composed of 17 boys, evaluated in March 2022, matched with the same BMI-z characteristics. Stature, body mass, fat mass (FM), fat free mass (FFM), flexibility (FLEX), 25(OH)D, absolute CRF (CRFabs) and relative (CRFrel) were assessed. The Supine-to-Stand test (STSTIME) execution time was used to assess motor performance and motor competence by the motor patterns used in execution (STSMC). considering p<0.05 significant. The results showed that, post-pandemic, there were impairment on 25(OH)D, FLEX, STSTIME e CRF (p<0.05). Both eutrophic and overweight groups reduced 25(OH)D concentrations (p<0.001) and increased STSTIME (p=0.02) but did not modify STSMC. Regarding CRF, eutrophic individuals showed lower CRFabs and CRFrel values (p≤ 0.005), however no changes in the overweight group. We conclude that social isolation impaired the 25(OH)D concentrations and motor performance of adolescents. However, it stands out that the eutrophic were the most impacted with social isolation, as they showed unfavorable effect also on CRF.

This study aimed to observe adolescents’ changes and individual responses regarding the anthropometry, cardiometabolic profile, vitamin D concentrations, physical fitness, and motor competence upon immediate return and three months of school activities after lockdown. Methods: The study included 28 adolescents (14.8 ± 0.8 years) of both sexes. Anthropometric measures, body composition, cardiometabolic parameters, physical fitness, and motor competence were assessed. A paired t-test was used to compare the frequencies of respondents and the effect size of the results, considering significant p < 0.05. Results: After three months of school activities, adolescents changed their body composition, reducing % fat mass (p = 0.008) and increasing fat-free mass (p = 0.008). In terms of physical fitness, there was increased abdominal resistance (p < 0.001; ES = −0.42) and motor performance, with reduction in supine-to-stand test time (p < 0.001; ES = 0.53). There were very beneficial effects in reducing resting heart rate (p ≤ 0.001; ES = 0.61) and increasing vitamin D concentrations (p < 0.001; ES = −0.61). After three months of a school routine, the proportions of change in respondents were similar between girls and boys and eutrophic individuals and overweight individuals. Conclusions: Returning to school activities after lockdown was important for the recovery of vitamin D concentrations, physical fitness, and motor competence, whose responses were independent of the level of adiposity and sex of the adolescents.

Strategies for controlling hypertension include reducing excess fat and increasing muscle mass. However, the effects of exercise interventions on hypertension in adolescents have been little investigated. The purpose was to evaluate the effect of 12 weeks of aerobic exercise on systolic blood pressure (SBP) and diastolic blood pressure (DBP) and the cardiometabolic profile of overweight hypertensive and non-hypertensive boys. The sample included 107 boys diagnosed as overweight, aged between 12 and 17, divided into two non-hypertension groups, one control (GCN, n = 14) and one with exercise (GEN, n = 55), as well as two groups of hypertensives, one control (GCH, n = 12) and one with exercise (GEH, n = 26). The boys were assessed at the study baseline and after 12 weeks in terms of anthropometric parameters, biological maturation, SBP, DBP and mean blood pressure (MBP), lipid, and metabolic profile. The aerobic training programs lasted 12 weeks and were carried out in three weekly sessions at different intensities. The high-intensity interval training session lasted around 35 min at an intensity of 80–100% of the reserve heart rate, and the moderate-intensity of continuous training session lasted 60 min at an intensity of 35–75% of the reserve heart rate. Caloric expenditure was equivalent between the exercises (p = 0.388). CGN and CGH participated only in school physical activities. Repeated measures analysis of variance and clinical effect analysis using Cohen’s effect size were used, with a significance level established at p < 0.05. After 12 weeks, all groups increased their height (p < 0.05), but only the exercise groups showed a reduction in anthropometric variables (p < 0.05), with a possibly beneficial effect in GEN (d = − 0.203; p = 0.003). No differences were found in the variables for the GCN. The GCH and GEH groups reduced SBP (p < 0.05), but only GEH showed a reduction in DBP (p = 0.005) and MBP (p = 0.001). In relation to the lipid profile, GEH maintained HDL-c close to baseline values, while GCH showed a reduction in HDL-c (p = 0.021). Regarding the clinical effect of exercise on hypertension, GEH showed a large and very beneficial effect size on DBP (d = − 0.916; p = 0.006) and MBP (d = − 0.926; p = 0.005). Conclusion: Hypertensive boys who practiced physical exercise showed greater effects in reducing blood pressure, indicating the importance of non-drug therapeutic management in overweight adolescents. Trial registration: Brazilian Registry of Clinical Trials RBR-4v6h7b / RBR-6343y7.

Introduction: Lactate is a substance that, over the years, has been responsible for numerous effects, mainly linked to muscle fatigue, being recently highlighted in systemic processes and muscle regeneration, which still has many points to be clarified, one of them being the participation of lactate in this process. Objective: Verify the effect of lactate on muscle recovery in in vivo and in vitro models. Methods: The search was conducted in five databases (16 June 2022) (PROPERO nº CRD42020209324), using the search words in English and Portuguese: ‘lactate’, ‘lactic acid’, ‘muscle regeneration’, ‘MyoD protein’, and ‘myogenin’. We included experimental and in vitro studies that investigated the use of lactate in relation to muscle (all species and both sexes – males and females). The methodological quality was assessed by a specific questionnaire for in vitro and in vivo studies. Results: Eight articles were selected, of which three studies were found exclusively in vitro, one exclusively in animal models, and four studies with in-vitro models and animal models. Three studies scored overall methodological quality above 90%, another three between 80-90% and two between 70-75%. Both types of studies showed results that may point to the mechanism by which lactate acts in the proliferation and differentiation of myoblasts, either by the action of myogenic regulatory factors (MRFs) or by the actions in the metabolism of these cells. Conclusion: The lactate presence in myoblasts strongly suggests a correlation with the expression of regulatory molecules during muscle regeneration. Future studies must investigate this correlation to advance our understanding of the regulatory mechanisms involved in this process

The aim of this study was to evaluate the mediation role of muscle quantity in the relationship between physical fitness and cardiometabolic risk factors (CMRF) in adolescents. This cross-sectional study conducted with 120 adolescents of both sexes, aged between 10 and 17 years. Body mass, height, fat mass (FM), lean mass, blood pressure, high-density lipoprotein, low-density lipoprotein, triglycerides, glucose, insulin, cardiorespiratory fitness (CRF) and 1 repetition maximum strength (1-RM) with evaluation of the leg press 45° (RM-leg), bench press (RM-bench) and arm curl (RM-arm). Body mass index z-score, appendicular skeletal muscle mass, appendicular skeletal muscle mass index, lean mass index (LMI), muscle-to-fat ratio (MFR), age at peak height velocity, and CMRF z-score were calculated. The direct relation between FM and CMRF was mediated by the LMI (26%) and inverse relation between CRF and CMRF was mediated by the LMI (26%). For girls, the direct relation between FM and CMRF was mediated by the LMI (32%); the inverse relation between CRF, RM-leg, RM-arm and CMRF was mediated by the LMI (32%, 33%, and 32%, respective). For boys, the indirect effect was not significant, indicating that LMI is not a mediator in the relation between FM, CRF, 1-RM with CMRF. The direct relation between RM-leg and CMRF was mediated by the MRF (16%). This finding evidenced the importance of promoting a healthy lifestyle to improve physical fitness levels and the quantity of muscle mass in adolescents.

Background: Adiponectin is an anti-inflammatory cytokine secreted by adipose tissue, has been associated with adiposity and cardiometabolic risk, and has controversial results with muscular fitness. The aim of this study was to analyze the interaction of 1-minute abdominal test in the relationship between adiposity, body composition, cardiometabolic risk and adiponectin concentration in adolescents. Methods: This is a cross-sectional study conducted with 62 adolescents of both sexes, aged 11 to 16 years, approved by the Ethics Committee of Research in Humans (CAEE: 62963916.0.0000.5223). Body mass, height, abdominal circumference (AC), waist circumference (WC), fat mass (FM), fat-free mass (FFM), high density lipoprotein (HDL-c), low density lipoprotein (LDL-c), triglycerides (TG), adiponectin, systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean blood pressure (MBP), 1-minute abdominal test (ABD) were measured. Body mass index (BMI), z-score BMI (BMI-z), triponderal mass index (TMI), and waist-to-height ratio (WHtR) were calculated. The macro PROCESS for SPSS v.24.0 was used for moderation analyses, with linear regression models. Results: Inverse interactions were found for adiposity (BMI, BMI-z, TMI, AC, WC, WHtR), body composition (FM, FFM) and CMRF (SBP, DBP, MBP, TG) versus 1-minute abdominal test with adiponectin concentration, demonstrating that abdominal test is a moderator in these relationships. Conclusion: We conclude that 1-minute abdominal test may play an important role in the relationship between obesity and cardiometabolic risk. We found that muscular fitness can confer a protective effect on adolescents with high levels of abdominal test.

This study aimed to evaluate the effect and individual responsiveness after 12 weeks of high-intensity interval training (HIIT) and moderate-intensity of continuous training (MICT) on adiponectin, cardiometabolic risk factors and physical fitness in overweight adolescents. This study was participated by 52 adolescents, both sexes, 11 and 16 years old, separated into HIIT (n = 13), MICT (n = 15), and control group (CG, n = 24). Body mass, height, waist circumference (WC), fat mass (FM), fat-free mass (FFM), blood pressure, high-density lipoprotein (HDL-c), low-density lipoprotein (LDL-c), triglycerides, glucose, insulin, adiponectin, and C-reactive protein (CRP) were evaluated. Body mass index z-score (BMI-z), waist-to-height ratio (WHtR), insulin resistance, and insulin sensitivity were calculated. Resting heart rate (HR_rest), peak oxygen consumption (VO_2peak), right handgrip strength (HGS-right), left handgrip strength (HGS-left), and abdominal resistance (ABD) was evaluated. HIIT session lasted around 35 min and MICT of 60 min of exercises on stationary bicycle, three times a weekday for 12 weeks. ANOVA, effect size, and prevalence of responders were used for statistical analysis. HIIT reduced BMI-z, WHtR, LDL-c, and CRP, while increased of physical fitness. MICT reduced HDL-c, while increased of physical fitness. CG reduced FM, HDL-c, and CRP, while increased FFM and HR_rest. Frequencies of respondents in HIIT were observed for CRP, VO_2peak, HGS-right, and HGS-left. Frequencies of respondents in MICT were observed for CRP and HGS-right. Frequencies of no-respondents in CG were observed for WC, WHtR, CRP, HR_rest, and ABD.   Conclusion: Interventions with exercises were effective to adiposity, metabolic health, and physical fitness improvements. Individual responses were observed in inflammatory process and physical fitness, important changes in overweight adolescent’s therapy. Trial registration number and date of registration: This study was registered with the Brazilian Registry of Clinical Trials (REBEC), the number RBR-6343y7, date of registration May 3, 2017. What is Known: • Effect of regular physical exercise positively affects overweight, comorbidities, and metabolic diseases, recommended mainly for children and adolescents. What is New: • Due to the great inter-individual variability, the same stimulus can provide different responses; adolescents who benefit from the stimulus are considered responsive. • Intervention of HIIT and MICT did not alter the concentrations of adiponectin; however, the adolescents presented responsiveness to the inflammatory process and physical fitness.

Objective: The aim of this study was to analyze which equation best estimates maximal heart rate (HRmax) for the pediatric population according to body mass. Data source: We performed a meta-analysis (PROSPERO No. CRD42020190196) of cross-sectional studies that aimed to validate or develop HRmax equations and that had children and adolescents as samples. The search was conducted in Scopus, Science Direct, Web of Science, PubMed, and Biblioteca Virtual em Saúde with the descriptors “prediction or equation,” “maximal heart rate,” “maximum heart rate,” “determination of heart rate,” children, and adolescent. The TRIPOD Statement tool was used to assess the methodological quality and the relevant data were extracted for analysis. The meta-analysis was conducted in the Comprehensive Meta-Analysis, adopting p<0.05 and a 95% confidence interval (CI). Data synthesis: In total, 11 studies were selected, of which 3 developed predictive equations, 10 performed external validity of the preexisting models, and 1 incremented values related to equations already developed. The results of the methodological quality analysis showed a moderate rating in most studies. The 164 + (0.270 × HRres) – (0.155 × body mass) + (1.1 × METs) + (0.258 × body fat percent) (r=0.500, 95%CI 0.426–0.567, p<0.001) and 166.7+ (0.46 × HRres) + (1.16 × maturation) (r=0.540, 95%CI 0.313–0.708, p<0.001) equations presented stronger correlations with measured HRmax in nonobese adolescents. The predictive model developed by 208 – (0.7 × age) showed a greater accuracy among the possible models for analysis (SDM=-0.183, 95%CI -0.787 to -0.422, p=0.554). No specific predictive equation was found for obese adolescents. Conclusions: Future research should explore new possibilities for developing predictive equations for this population as a tool to control exercise intensity in the therapeutic management of childhood and adolescent obesity.