Fat-Free Mass Index for body composition analysis in pediatric sport: a cross-sectional study.

BACKGROUND: Analyzing fat free mass (FFM) helps sport professionals during the prescription of sport training for children and adolescents in a sport initiation program. In this way, it is possible to determine fat mass (FM) (FFM subtracted from total body weight) and design interventions to increase FFM and reduce %F, making it possible to maximize performance in relation to the physical demands of sport. However, there is still no reliable anthropometric index to analyze FFM in this population. The aim the present study was to develop the Fat-Free Mass Index (FFMI) for pediatrics of both sexes. METHODS: Cross-sectional study with a sample composed of 254 pediatrics (139 males [age: 13.0±2.3] and 115 females [age: 12.5±2.2]), from a sports initiation school. We divided the sample into the groups: 1) development (N.=169); and 2) cross-validation (N.=85). The body composition was analyzed by dual-energy X-ray absorptiometry (DXA), in addition we acquired anthropometric data (height, body weight and hip circumference) for the development of the FFMI - Pediatric (FFMIp). By means of linear regression we tested the predictive power of FFM using DXA as a reference method, then we developed FFMIp and tested its reliability and validity in relation to DXA. RESULTS: FFMIp consisted of: -16.679 + (0.615 × body mass (kg)) - (2.601 × sex) + (0.618 × age(years)) - (0.332 × hip(cm)) + (0.278 × stature(cm)), where for sex 0 = male and 1 = female. For the FFM analysis, FFMIp showed no significant difference from DXA (P>0.05). It also showed significant accuracy (Cb>0.960), precision (ρ>0.990) and agreement (CCC>0.960) for both groups (development and cross-validation). CONCLUSIONS: Pediatric FFMI proposed by this study proved to be valid for the analysis of fat-free mass in pediatric athletes of sports initiation of both sexes.

Effects of high-intensity interval training in combination with detraining on mental health in women with polycystic ovary syndrome: A randomized controlled trial.

This study aimed to investigate the effects of high-intensity interval training (HIIT) and detraining on the quality of life and mental health of 23 women with polycystic ovary syndrome (PCOS). Participants were randomly assigned to the HIIT group (n = 12) [26.0 ± 3.92] and the control group (n = 11) [26.6 ± 4.68]. HIIT sessions comprised 40-60 min, 3 days a week for 12 weeks, followed by detraining for 30 days. We assessed the quality of life using the Short Form Health Survey (SF-36) and mental health by the Depression, Anxiety, and Stress Scale (DASS-21), and we compared group changes on these variables at three time points: 1) at baseline, 2) after 12 weeks of HIIT (or no training), and 3) after 30 days of detraining (or no training). The participants were classified as overweight and had a high percentage of body fat (41.5%) and irregular menstrual cycles (amenorrhea) (66.7%). Throughout training, participants in the HIIT group reported improvements in domains of the quality of life: functional capacity (M = 80.4 ± 3.4 vs. M = 87.0 ± 3.1), physical role functioning (M = 72.5 ± 9.4 vs. M = 81.8 ± 9.7), and general health perception (M = 48.6 ± 4.6 vs. M = 69.0 ± 5.8). Regarding anxiety symptoms (M = 6.4 ± 1.6 vs. M = 3.7 ± 0.7) and depression symptoms (M = 6.7 ± 1.6 vs. M = 3.8 ± 0.9), those reduced significantly after HIIT. After a 30-day detraining period, there was an increase in the significant change in the quality of life; however, domains of mental health showed instability. In summary, the HIIT program promoted improvements in the quality of life and mental health in women with PCOS. The 30 days of detraining changed the benefits in the quality of life and stability in the changes in mental health domains.

Can Post-Exercise Hemodynamic Response Be Influenced by Different Recovery Methods in Paraplegic Sportsmen?

Post-exercise hypotension is of great clinical relevance and also in sports training settings, as recovery speed is important. The aim of this study was to compare the influence of different recovery methods on post-exercise hemodynamic response. Twelve male paraplegic sportsmen (25.40 ± 3.30 years) performed a strength training (ST) session using the bench press exercise. After the ST, three recovery methods were randomly performed over a 15-min period: passive recovery (PR), cold-water (CW) and dry needle (DN). Blood pressure (BP), heart rate (HR) and myocardial oxygen were measured before and post ST, as well as post the recovery method. Results: Dry needling induced lower systolic blood pressure (SBP) immediately after the treatment when compared with the other recovery methods, but the contrary was observed at 50 and 60-min post recovery, where records with DN exhibit higher mean values (η2p = 0.330). There were no differences in post-exercise diastolic BP and mean BP between recovery methods. There was a significantly higher HR after the PR method, when compared with CW and with DN (η2p = 0.426). The same was observed for double product and for myocardial oxygen, though with a larger effect size (η2p = 0.446). We conclude that dry needling seems to induce a faster SBP lowering immediately after the procedure but at 50-min post procedure the cold-water method showed better result. As for HR, both procedures (DN and CW) showed a better recovery when compared with passive recovery, along the several moments of measurement.

Impact of social isolation on the level of physical activity in young Brazilian athletes caused by COVID-19.

BACKGROUND: Social detachment to prevent the spread of the COVID-19 pandemics in the year 2020 can significantly contribute to the physical inactivity of citizens worldwide. The study aimed to analyze the level of physical activity by identifying the training methods used during the social isolation resulting from the COVID-19 pandemic. METHODS: Sixty-eight Brazilian athletes (both sexes, 14.7±1.68 years) answered and adapted the International Physical Activity Questionnaire (I-PAQ) through an online platform. Participants were asked to report their level of physical activity before and during the period of social distance. RESULTS: According to our results, 67.7% of the interviewed athletes said they were able to adapt their sports training to the isolation environment under the guidance of a distance physical education professional. Only 4.38% of the sample was not training under such supervision and, therefore, inactive. Among the activities performed in the isolation environment, calisthenics was the primary practice (effect size: ƒ2=0.50, P<0.0001) and the sport practiced at home was the secondary practice (effect size: ƒ2=0.27, P=0.004). During the pandemic, the training hours of athletes reduced significantly from ~3h to ~1h per day (effect size: 1.74, P<0.0001), as well as the perceived intensity decreased from "high" to "moderate" (effect size: 1.38, P<0.0001). The weekly training frequency decreased from ~6 to 7 days to ~3 to 5 days (effect size: 0.40, P=0.03). CONCLUSIONS: Despite the social distance and the reduced pace of training, the young Brazilian athletes analyzed managed to remain physically active during the COVID-19 pandemic.

Biological age, testosterone, and estradiol as discriminating factors of muscle strength levels in young athletes.

BACKGROUND: Neuromuscular fitness can be influenced at puberty by a steroid hormones, such as testosterone (TRT) and estradiol (EST). However, more information is needed to assess the reliability between the discriminatory power of biological age (BA) markers with the discriminatory power of TRT and EST in relation to muscle strength in young athletes who are at puberty. The aim of this paper was to analyze BA, TRT and EST as discriminating factors of upper limb (ULS) and lower (LLS) strength levels in young athletes. METHODS: The sample of 81 young athletes (54.4% female and 45.6% male; age: 11.4±1.08). Hormones were analyzed by chemiluminescence, BA markers by anthropometric variables and body composition by tetrapolar bioimpedance. ULS was verified by the medicineball launch test and LLS by the countermovement jump test on a force platform. RESULTS: EST was reliable for discriminating ULS (P<0.05) and LLS (P<0.05) in females. TRT showed reliability in discriminating ULS (P<0.05) and LLS (P<0.05) in males. BA was significant in discriminating ULS (P<0.0001) in females and ULS (P=0.002) and LLS (P<0.0001) in males. BA showed significant reliability with hormonal analyzes (P<0.05). CONCLUSIONS: That hormonal concentrations are reliable in discriminating ULS and LLS of young athletes of both sexes. BA was shown to be effective in discriminating ULS (in both sexes) and LLS (in males). BA showed significant reliability with hormonal analyzes (ULS and LLS in male sex; LLS for female sex).

The influence of biological maturation and neuromuscular performance on peak bone mineral density in children.

BACKGROUND: The growth and development cycle of the adult is characterized by substantial changes in physical size and maturity, and is controlled by the simultaneous influence of genetic components and the environment. Changes in the development of bones, muscles and adipose tissue are among the most important aspects of adolescent physical development. The aim of this research was to examine the correlation between bone mineral density (BMD) and neuromuscular performance in children at different stages of maturation. METHODS: The study included 31 participants of both sexes (11.7±1.89 years). Body composition was assessed through bone densitometry using an energy duo X-ray source. The neuromuscular performance of the upper limbs was analyzed by the medicine ball hand grip and throwing tests. The lower limbs by the vertical counter-motion jump test, and skeletal maturation was analyzed by bone age. Maturation was used as an effect control between the association of BMD and neuromuscular performance. RESULTS: The results demonstrated significant associations between the performance of upper (P<0.0001) and lower (P=0.01) limbs and BMD. On inter-group comparison for only the accelerated maturational stage, male participants had greater BMD than female participants (P=0.001; effect size 3.13). Regarding the maturational stages, male participants in the accelerated maturational stage demonstrated higher BMD than those in the normal and delayed maturational stages (P=0.04; effect size 3.10), whereas female participants did not demonstrate significant differences in BMD accumulation. CONCLUSIONS: BMD has a strong correlation with the neuromuscular performance of upper and lower limbs of children of both sexes.

Relação entre a maturação e a velocidade de membros superiores / Maturity of relationship with the speed of upper limbs

A maturação pode ser definida como um fenômeno biológico qualitativo, relacionando-se com o amadurecimento das funções de diferentes órgãos e sistemas. Esse estágio pode ser classificado em atrasado, normal e avançado. A maturação pode interferir em algumas capacidades, tanto de características físicas como de aspectos cognitivos. O presente estudo tem por objetivo verificar se a idade óssea, quanto indicador de maturação corporal, possui correlação com a velocidade de membros superiores. O estudo foi realizado com 181 crianças com idade entre 8 e 14 anos do sexo feminino e masculino, iniciantes de uma prática esportiva. Para a predição da idade óssea foi utilizada a equação de Cabral (2011) que é realizada através de dados antropométricos conforme padronização da (ISAK). Para medição da velocidade dos membros superiores, foi utilizado o teste de golpeio de placas segundo normas da EUROFIT. O resultado obtido na análise de variância identificou diferenças no desempenho do teste de golpeio de placa para as meninas, no qual as que se encontram no estágio maturacional acelerado apresentaram piores respostas de velocidade quando comparadas com as que se encontram em estágio normal de maturação (F=11,21; p=< 0,001); já para os meninos os estágios maturacionais não demonstraram diferenças para a VMMSS. Através da correlação linear de Pearson obteve-se uma correlação negativa e não significante, onde meninos (r=-0,156; p=0,144) e meninas (r=-0,018; p=0,866). Os resultados mostraram que embora a maturação seja um fator importante para o desenvolvimento de certas habilidades e manutenções das existentes, não há correlação significativa expressa entre os fatores. Porém, o pico de crescimento ocasionado pelo processo de desenvolvimento pode ser um fator interferente na capacidade. Portanto, a conclusão extraída do estudo revela que não houve correlação significativa entre a idade óssea e a velocidade de membros superiores e que quando se atinge o pico de crescimento, pode haver um pior resultado no teste de golpeio....(AU)

Maturation can be defined as a qualitative biological phenomenon, relating to the maturation of the functions of different organs and systems. This stage can be classified into late, normal and advanced. The maturation may interfere with some capabilities of both physical characteristics and cognitive aspects. This study aims to determine the bone age, the body maturation indicator, has correlated with the speed of the upper limbs. The study was conducted with 181 children aged 8 to 14 years of women and men, beginners a sport. For the prediction of bone age was used Cabral equation (2011) which is held by anthropometric data according to standardized (ISAK) for measuring the speed of the upper limb, has been used to strike the second test plates EUROFIT standards. The result obtained in the analysis of variance identified differences in performance of the plaque strike test for girls, in which they are in accelerated maturation stage showed lower speed responses when compared to those found in normal ripening stage (F = 11.21; p = <0.001); while for boys the maturational stages showed no difference for VMMSS. Through the Pearson linear correlation was obtained a negative and no significant correlation, where boys (r = -0.156; p = 0.144) and girls (r = -0.018; p = 0.866). The results showed that although maturation is a major factor in the development of certain existing skills and maintenance, there is no significant correlation between factors expressed. However, the peak increase caused by the development process can be an influencing factor on capacity. Therefore, the conclusion drawn from this study revealed that there was no significant correlation between age and bone speed of the upper limbs and when growth reaches the peak, there may be a worse outcome in Bang test....(AU)

Skeletal age and explosive strength in young volleyball players / Idade óssea e força explosiva de jovens praticantes de voleibol

Abstract Identifying different anthropometric, physiological and motor aspects is essential to obtain success in sports practice. However, these components may be developed in same age subjects differently, in part due biological development. The aim of the study was compare and correlate the explosive strength to biological maturation by sex, obtained by estimation of skeletal age based on anthropometric variables. The sample consisted of 239 subjects of both sexes, aged 10 to 13 years. Maturation was assessed by skeletal age predictive equation and upper and lower limbs explosive strength using medicine ball throw test and vertical jump, respectively. Skeletal age was assessed by skeletal age using a predictive anthropometrical based equation. Upper and lower limbs explosive strength were evaluated by medicine ball throwing test and vertical jump test, respectively. Post hoc analysis showed delayed biological development subjects had worst medicine ball throwing test performance than accelerated boys (p=0.001; d=0.96) and girls (p< 0.01; d= 2.01); regarding to vertical jump test, worst performance was also detected to maturational delayed boys when compared to accelerated ones (p=0.24; d=1.1) and girls (p=0.007; d=0.75). Regression analysis showed skeletal age explained variance of 36% and 19.2% for boys and 45.2% and 16.1% for girls upper and lower limbs explosive strength. Skeletal age is positively related to upper and lower limbs explosive strength and show higher performance for accelerated biological development young players when compared to delayed ones, independently from sex.

Resumo Para se alcançar o sucesso no esporte, a identificação de diferentes aspectos antropométricos, motores e fisiológicos são imprescindíveis. Porém, esses componentes podem se desenvolver diferentemente em indivíduos na mesma faixa etária, em parte pelo desenvolvimento biológico. O objetivo do estudo foi comparar e relacionar a força explosiva com a maturação biológica de acordo com o sexo. A amostra foi composta por 239 sujeitos, com idades entre 10 a 13 anos. A idade óssea foi estimada por uma equação preditora baseada em variáveis antropométricas. A força explosiva de membros superiores e inferiores foram avaliadas através do teste de arremesso de medicine ball e de salto vertical, respectivamente. A análise de post hoc mostrou que os sujeitos com desenvolvimento biológico atrasado obtiveram o pior desempenho no teste de arremesso de medicine ball quando comparados com o grupo acelerado dos meninos (p=0.001; d=0.96) e meninas (p< 0.01; d= 2.01); em relação ao teste de salto vertical, desempenho inferior também foi observado para o estágio atrasado quando comparado com o grupo acelerado dos meninos (p=0.24; d=1.1) e meninas (p= 0.007; d=0.75). Análise de regressão demonstrou que 36% e 19,2% da variância no desempenho da força explosiva de membros superiores e inferiores foi compartilhada pela idade óssea dos meninos, e 45,2% e 16,1%, respectivamente, nas meninas. Conclui-se que a força explosiva de membros superiores e inferiores se relaciona de forma positiva com a idade óssea, sendo o desempenho destes componentes superiores em jovens com desenvolvimento biológico acelerado, quando comparados com o desenvolvimento atrasado, independente do sexo.