RESUMO
Infrared thermography (IRT) is a technology easy to use for clinical purposes as a pre-diagnostic tool for many health conditions. However, the analysis process of a thermographic image needs to be meticulous to make an appropriate decision. The adipose tissue is considered a potential influence factor in the skin temperature (Tsk) values obtained by IRT. This study aimed to verify the influence of body fat percentage (%BF) on Tsk measured by IRT in male adolescents. A total of 100 adolescents (16.79 ± 0.97 years old and body mass index of 18.41 ± 2.32 kg/m²) was divided into two groups through the results of a dual-energy X-ray absorptiometry analysis: obese (n = 50, %BF 30.21 ± 3.79) and non-obese (n = 50, %BF 11.33 ± 3.08). Thermograms were obtained by a FLIR T420 infrared camera and analyzed by ThermoHuman® software version 2.12, subdividing the body into seven regions of interest (ROI). The results showed that obese adolescents presented lower mean Tsk values than the non-obese for all ROIs (p < 0.05), with emphasis on the global Tsk (0.91 °C) and anterior (1.28 °C) and posterior trunk (1.18 °C), with "very large" effect size values. A negative correlation was observed in all the ROI (p < 0.01), mainly in the anterior (r = -0.71, p < 0.001) and posterior trunk (r = -0.65, p < 0.001). Tables of thermal normality were proposed for different ROIs according to the classification of obesity. In conclusion, the %BF affects the registered Tsk values in male Brazilian adolescents assessed by IRT.
Assuntos
Tecido Adiposo , Termografia , Masculino , Humanos , Adolescente , Temperatura Cutânea , Obesidade , Índice de Massa Corporal , Absorciometria de Fóton , Composição CorporalRESUMO
This study examined individual, task, and environmental constraints that influence the career progression of youth Brazilian elite basketball players and the probability of reaching Novo Basquete Brasil (NBB) and to determine if the association of the relative age effect (RAE) is a key factor in the career progression. The sample consisted of 4,692 male players who were registered to participate in at least one U15, U17, or U22 youth Brazilian basketball championship between 2004 and 2018. Athletes who reached a high-performance level were coded like NBB players (9.6%). The birthdates, height, body mass, playing position, geographic region, club, competition category, and team performance were retrieved from the official data archive of the Brazilian Basketball Confederation and the National Basketball League. The maturity status was estimated using the predicted age at peak height velocity. A binary logistic regression examined the influence of each characteristic on the probability of a youth Brazilian basketball player to reach the NBB. The receiver operating characteristic (ROC) curves and the associated area under the curve (AUC) were used to assess the discriminant ability of the model. The taller and younger players not selected early into national teams, without specialization by playing position, who participated in U22 national championship, migrated to the southeast region, and remained in the formation process over time have a greater chance to reach the NBB. The ROC curve demonstrated an AUC of 93%. A combination of individual, task, and environmental characteristics influences the sport career of a young Brazilian basketball player in reaching the NBB. Further, early-maturing athletes have a greater chance to reach higher performances. RAE influences lower-level categories, but not a "NBB player's" career progression. The coaches, stakeholders, and practitioners should perform a holistic evaluation of sport talent in terms of a constraint-based theoretical model with the aim of avoiding bias produced by the maturational status and RAE in the youth Brazilian elite basketball.
RESUMO
Horta, TAG, Bara Filho, MG, Coimbra, DR, Miranda, R, and Werneck, FZ. Training load, physical performance, biochemical markers, and psychological stress during a short preparatory period in Brazilian elite male volleyball players. J Strength Cond Res 33(12): 3392-3399, 2019-The aim of this study was to assess the relationship between training load (TL) and physical performance, biochemical markers, and psychological stress during a short preparatory period (SPP) in Brazilian elite male volleyball players. Twelve volleyball players from a team competing in the Brazilian Men's Volleyball Super League were enrolled (26.9 ± 4.6 years). Countermovement jump (CMJ), creatine kinase (CK), testosterone (T), cortisol (Cr), T/Cr ratio, and Recovery and Stress Questionnaire for athletes (RESTQ-Sport) were collected at baseline, after second, fourth, and sixth week. Training load was quantified daily using the rating of perceived exertion. Differences were noted between total weekly training load (TWTL) (F3,33 = 50.907; p = 0.0001), CK (F3,33 = 16.157; p = 0.0001), and T (F3,33 = 3.283; p = 0.03). No differences were seen in CMJ (F3,33 = 1.821; p = 0.16), Cr (F3,33 = 2.409; p = 0.08), or T/Cr ratio (F3,33 = 1.527; p = 0.23). The RESTQ-Sport demonstrated differences between moments in social stress (F3,33 = 2.297; p = 0.04; η = 0.25), success (F3,33 = 4.350; p = 0.01; η = 0.19), general well-being (F3,33 = 4.465; p = 0.01; η = 0.36), and injury (F3,33 = 2.792; p = 0.05; η = 0.62). The results showed a significant correlations of small to moderate magnitude between TWTL and CK (r = 0.32; p = 0.05). In conclusion, a short PP in volleyball leads to increased TL, CK level, and psychological stress. Training load was related with the increase of CK, suggesting muscle damage without increased physical performance.
Assuntos
Creatina Quinase/sangue , Condicionamento Físico Humano/fisiologia , Esforço Físico/fisiologia , Estresse Psicológico/etiologia , Voleibol , Adulto , Biomarcadores/sangue , Brasil , Teste de Esforço , Humanos , Hidrocortisona/sangue , Masculino , Condicionamento Físico Humano/psicologia , Desempenho Físico Funcional , Inquéritos e Questionários , Testosterona/sangue , Fatores de Tempo , Voleibol/fisiologia , Voleibol/psicologia , Carga de Trabalho , Adulto JovemRESUMO
Abstract It is necessary to clarify if BM and track and field performance can modulate the perception about RPE-session. The purpose of the present study was to verify if biological maturity and track and field-specific performance can be associated with training load (RPE-session method). Seventy-five young athletes (13-15 years old) of both genders participated in the present study. The experimental protocol lasted seven consecutive days. Performance tests (75-m running, long jump, 250-m running, shot put and 1000-m running) were made on the first day. After 48 hours, five days of track and field training it was prescribed, each day represents a training of each performance test. All training sessions had the same duration (120 min). The value of the training load was obtained multiplying the RPE value with training session duration (in minutes). For girls, the training load of 250-m training was correlated with biological maturity (r = -0.36, p = 0.02, n = 37) and specific performance (r = 0.33, p = 0.04, n = 37). All other analyzes indicate that biological maturity and track and field-specific performance do not influence the training load based on RPE-session method. Training load based on RPE-session is not influenced by biological maturity and track and field-specific performance, therefore can be used to control the training load of young track and field athletes. To girls it is necessary a care to control the training sessions intensity of 250-m running.
Resumo É necessário esclarecer se a maturação biológica e o desempenho no atletismo podem modular a PSE da sessão. O objetivo do presente estudo foi verificar se a maturidade biológica e o desempenho específico no atletismo podem estar associados à carga de treinamento (método de PSE da sessão). Setenta e cinco jovens atletas (13-15 anos) de ambos os sexos participaram do presente estudo. O protocolo experimental durou sete dias consecutivos. Testes de desempenho (75 m de corrida, salto em distância, 250 m de corrida, arremesso de peso e 1000 m de corrida) foram feitos no primeiro dia. Após 48 horas, cinco dias de treinamento de atletismo foram prescritos, cada dia representa um treinamento de cada teste de desempenho. Todas as sessões de treinamento tiveram a mesma duração (120 min). O valor da carga de treinamento foi obtido multiplicando o valor do PSE com a duração da sessão de treinamento (em minutos). Para as meninas, a carga de treinamento de 250 m foi correlacionada com a maturidade biológica (r = -0,36, p = 0,02, n = 37) e desempenho específico (r = 0,33, p = 0,04, n = 37). Todas as outras análises indicam que a maturidade biológica e o desempenho específico no atletismo não influenciam a carga de treinamento com base no método da PSE da sessão. A carga de treinamento com base na PSE da sessão não é influenciada pela maturidade biológica e desempenho específico no atletismo, portanto, pode ser usada para controlar a carga de treinamento de jovens atletas de atletismo. Para as meninas é necessário cuidado para controlar a intensidade das sessões de treino de 250m de corrida.
RESUMO
Oxygen uptake (VO2) and heart rate (HR) kinetics after exercise are important indicators of fitness and cardiovascular health. However, these variables have been little investigated in resistance exercise (RE). The current study compared post-exercise kinetics of VO2 and the HR among different types of REs. The study included 14 males (age: 26.5±5.4 years, body mass: 80.1±11.4 kg, body height: 1.77±0.07 m, fat content: 11.3±4.6%) with RE experience. Dynamic muscle strength was measured using one repetition maximum (1RM) with regard to the half-squat, bench press, pull-down, and triceps pushdown exercises. The participants performed a maximum number of repetitions at 80% of 1RM for each exercise, separated by a recovery period of 60 minutes. VO2 was measured using ergospirometry. VO2 and HR kinetics were assessed using the time constant of the recovery curves, and excess oxygen consumption (EPOC) was calculated afterward. Significant differences were not observed across the exercises with regard to VO2 kinetics. However, the half-squat exercise elicited a greater EPOC than the bench press and triceps pushdown exercises (p<.05). HR kinetics was slower for the half-squat exercise than for the other exercises (p<.05). These findings confirm that the type of RE influences both the cardiac autonomic response post-exercise and EPOC, but not VO2 kinetics.