To reduce transmission of the coronavirus, the Brazilian government adopted containment measures to control the virus’ spread, including limitations to the practice of physical activity. It was aimed to analyze the effects of COVID-19 quarantine on physical activity levels, energy expenditure, quality of life, and level of stress in a sample of the Brazilian population. The sample included 426 participants (7 to 80 years). The International Physical Activity Questionnaire, Short form survey-36 (SF-36), and Stress Perception Scale, were used to assess the level of physical activity, quality of life and stress, respectively. The anthropometric data was used to the assessment of body mass index and basal metabolic rate. Body weight increased significantly in all sample (p < 0.05). During the pandemic, 84% of the sample indicated a low level of physical activity. Furthermore, weekly energy expenditure decreased significantly in all age groups during the pandemic (children p < 0.0001; adolescents: p < 0.0001; adults p < 0.001, and elderly p < 0.0001). All aspects of quality of life, significantly reduced in both sexes in all age groups (p < 0.05). With the exception of children, stress levels increased significantly during the pandemic (adolescents: male: p = 0.003, female: p < 0.05; adults: male: p = 0.003, female: p = 0.01, and elderly: male: p = 0.02, female: p = 0.03). Findings from the present study suggests that COVID-19 social isolation has negatively affected Brazilian’ physical activity and quality of life.

Background: Endocrine mechanisms can be a determining factor in the neuromuscular performance of young athletes. Objective: The objective of the present study was to relate maturational and hormonal markers to neuromuscular performance, as well as to verify whether young athletes with different testosterone levels show differences in muscle strength. Methods: The sample consisted of 37 young male Brazilian athletes (11.3 ± 0.94 years) who were members of a sports initiation project. Hormonal markers were analyzed biochemically by blood samples, and maturation markers by mathematical models based on anthropometry. Body composition was verified by tetrapolar bioimpedance. The performance of upper and lower limb strength and body speed were analyzed. Results: Hormonal and maturational markers were related to neuromuscular performance (p < 0.05). Young people with higher testosterone levels showed higher muscle strength (p < 0.05). Artificial neural networks showed that testosterone predicted the performance of upper limbs by 49%, and maturation by 60%. Maturation foreshadowed the performance of lower limbs by 30.3%. Conclusion: Biological maturation and hormonal levels can be related to neuromuscular performance, and young people with higher testosterone levels show superior muscle strength in relation to the others.

The aim of this study was to synthesize the evidence on the effects of active video games (AVGs) on mental health, physical fitness and body composition of children and adolescents. A search was conducted in the following databases: PubMed; MEDLINE (by Ovid); SportDiscus, Cochrane library systematic reviews (CENTRAL) and EMBASE with no language restrictions during October 2020. Reviews on the use of AVGs were included in the study. We use the AMSTAR (A MeaSurement Tool to Assess systematic Reviews) scale to analyze the methodological quality of the studies. Seventeen systematic reviews and meta-analyzes were included on the effects of AVGs with 30 to 4728 children and adolescents of both sexes with ages ranging from 6 to 19 years. In five studies, the population was overweight or obese. Regarding the quality, 12 studies were of moderate quality, two had high quality, two had low quality and one showed very low quality. The analyzed data indicate that the use of AVGs with a frequency of 1 to 3 times a week with durations of between 10 and 90 min per day shows positive effects on mental health and physical functioning. There was moderate quality evidence that AVGs can result in benefits for self-esteem, increased energy expenditure, physical activity and reduced body mass index in children and adolescents who used AVGs in the home environment. Further research is needed on this tool to help in the process of social isolation and consequently in promoting health and well-being.

Background: The biological maturation (BM) analyzed by peak height velocity (PHV) and bone age (BA), and lean body mass has been associated with the strength and muscle power of young athletes. However, the ability of BM (PHV and BA) and LM markers to predict muscle strength and power in young athletes remains uncertain. Objective: The Aim was determine the predicting power of BM markers (PHV and BA) and LM in relation to muscle power of upper and lower limbs and muscle strength of upper limbs in adolescent athletes at puberty. Methods: Ninety-two adolescent athletes (both sexes; age 12.4 ± 1.02 years) were assessed for body composition by dual-energy X-ray absorptiometry (DXA). Power of upper limbs (ULP), force handgrip (HG), vertical jump (VJ) and countermovement jump (CMJ) were recorded. BM was predicted by mathematical models to estimate PHV and BA. Multilayer artificial neural network analyses (MLP’s) were used to determine the power of prediction of LM, PHV and BA on muscle power and strength of upper- and lower-limbs of the athletes. Results: LM, BA and PHV were associated with HG (r>0.74, p0.60, p0.55, p0.53, p0.60, p<0.05) with BA and with PHV (r<0.83, p 72% of probability to predict the muscle power of upper- and lower-limbs, and the strength of the upper limbs; whereas PHV provides > 43% and bone age >64% in both female and male adolescent athletes. Conclusion: We identified that, like PHV and BA, LM is a strong predictor of low cost of both upper limbs muscle strength and upper and lower limbs power in adolescent athletes.

Background: In Paralympic powerlifting (PP), athletes with and without spinal cord injury (SCI) compete in the same category. Athletes with SCI may be at a disadvantage in relation to the production of muscle strength and the execution of motor techniques. Objective: To analyze the indicators force, dynamic and static, at different intensities, on performance in athletes with and without SCI. Methods: The sample was composed of two groups of PP athletes: SCI (30.57 ± 4.20 years) and other deficiencies (OD; 25.67 ± 4.52 years). Athletes performed a test of maximum isometric force (MIF), time to MIF (Time), rate of force development (RFD), impulse, variability and fatigue index (FI), dynamic tests Mean Propulsive Velocity (MPV), Maximum Velocity (Vmax) and Power. Results: There were differences in the SCI in relation to OD, 50% 1RM (p < 0.05), in relation to MPV and Vmax. There were no differences in the static force indicators. Regarding EMG, there were differences between the SCI triceps in relation to the previous deltoid (p = 0.012). Conclusion: We concluded that the static and dynamic strength indicators are similar in Paralympic powerlifting athletes with spinal cord injury and other disabilities.

This study aimed to identify the interactional relationships between maturation (biological age (BA)) and lean mass on strength development in young athletes from different sports. Using a cross-sectional study design, a sample of 64 young athletes (rowers, swimmers, jiu-jitsu, volleyball, soccer and tennis players) of both sexes (13.6 ± 1.17 years) were recruited. Body composition was assessed using dual energy bone densitometry with X-ray source (DEXA). Strength of upper limbs (ULS), force hand grip (HG), vertical jump (VJ) and jump against movement (CMJ) were recorded. BA was estimated from anthropometrics. BA relationships were identified with upper limb strength in all athletes, and with the lower limb strength of tennis players, only (p < 0.05). An interaction effect between lean mass and BA was found (η²p = 0.753), as was a local effect within the regression models (ƒ² ≥ 0.33). Athletes with a higher concentration of lean mass had superior upper and lower limb strength (p < 0.05). Lean mass showed a local effect (ƒ²) greater than that associated with BA. Although maturation is related to strength development, the strength of the relationship is mitigated by the accrual of lean mass. Specifically, the local effect of lean mass on muscle strength is broader than that of maturation, especially for lower limb strength.