RESUMO

The aim of this systematic review was to assess the effects of plyometric-jump training (PJT) on the physical fitness of youth with cerebral palsy (CP) compared with controls (i.e., standard therapy). The PRISMA 2020 guidelines were followed. Eligibility was assessed using the PICOS approach. Literature searches were conducted using the PubMed, Web of Science, and SCOPUS databases. Methodological study quality was assessed using the PEDro scale. Data were meta-analyzed by applying a random-effects model to calculate Hedges' g effect sizes (ES), along with 95% confidence intervals (95% CI). The impact of heterogeneity was assessed (I2 statistic), and the certainty of evidence was determined using the GRADE approach. Eight randomized-controlled studies with low-to-moderate methodological quality were included, involving male (n = 225) and female (n = 138) youth aged 9.5 to 14.6 years. PJT interventions lasted between 8 and 12 weeks with 2-4 weekly sessions. Compared with controls, PJT improved the muscle strength (ES = 0.66 [moderate], 95% CI = 0.36-0.96, p < 0.001, I2 = 5.4%), static (ES = 0.69 [moderate], 95% CI= 0.33-1.04, p < 0.001, I2 = 0.0%) and dynamic balance (ES = 0.85 [moderate], 95% CI = 0.12-1.58, p = 0.023, I2 = 81.6%) of youth with CP. Therefore, PJT improves muscle strength and static and dynamic balance in youth with CP compared with controls. However, more high-quality randomized-controlled trials with larger sample sizes are needed to provide a more definitive recommendation regarding the use and safety of PJT to improve measures of physical fitness.

RESUMO

El conocimiento nutricional es clave para la formación de hábitos alimentarios y en la modulación del comportamiento alimentario. La alimentación y nutrición son cruciales durante la adolescencia sobre todo en jóvenes deportistas. El objetivo de esta investigación fue analizar la validez teórica y los índices de discriminación y dificultad del cuestionario de conocimientos nutricionales aplicados en el deporte utilizando la teoría de respuesta al ítem en deportistas juveniles de 14 a 19 años. Este estudio instrumental se desarrolló en cinco fases: generación de ítems, revisión por panel de expertos, pilotaje, aplicación y depuración final. Participaron 261 adolescentes de 14 a 19 años e integrantes de disciplinas colectivas en selecciones Nacional y clubes profesionales. Se determinaron los índices de dificultad y de discriminación para cada uno de los ítems. Los ítems 1 (0,354) y 2 (0,285) del factor antes, 3 (0,315) y 6 (0,408) del factor durante, 7 (0,354) y 10 (0,408) del factor después, 3 (0,254) y 9 (0,231) del factor hidratación y, 2 (0,362) y 5 (0,323) del factor suplementación, fueron los que presentaron mayor grado de discriminación. El cuestionario de conocimientos nutricionales aplicados en el deporte está compuesto por 30 ítems divididos en cinco factores cada uno de ellos con seis ítems. La propuesta inicial del cuestionario es una herramienta valida teóricamente y con índices de dificultad y discriminación adecuados para evaluar el conocimiento nutricional en jóvenes deportistas. Su aplicación permite conocer potenciales brechas en conocimientos claves y diseñar estrategias educativas específicas para subsanarlas.

Nutritional knowledge plays a fundamental role in the formation of dietary habits and the modulation of eating behaviour. Nutrition and diet are crucial during adolescence, especially for young athletes. The purpose of this research was to analyse the theoretical validity and indices of discrimination and difficulty of the questionnaire on nutritional knowledge applied in sports using item response theory in youth athletes aged 14 to 19. This instrumental study was conducted in five phases: item generation, expert panel review, pilot testing, application, and final refinement. A total of 261 adolescents aged 14 to 19, who were members of national team and collective disciplines of professional clubs, participated. Difficulty and discrimination indices were determined for each item. Items 1 (0.354) and 2 (0.285) of the before factor, 3 (0.315) and 6 (0.408) of the during factor, 7 (0.354) and 10 (0.408) of the post factor, 3 (0.254) and 9 (0.231) of the hydration factor, and 2 (0.362) and 5 (0.323) of the supplementation factor showed the highest degree of discrimination. The questionnaire on nutritional knowledge applied in sports consists of 30 items divided into five factors, each with six items. The initial questionnaire proposal is a theoretically valid tool and with adequate difficulty and discrimination indices to evaluate nutritional knowledge in young athletes. Its application allows for identifying potential gaps in key knowledge and designing specific educational strategies to address them.

RESUMO

We aimed to examine the acute effect of mental fatigue on young basketball players' three-dimensional multiple object tracking (3D-MOT) skills. Our participants were 12 adolescent basketball players (M age = 16.66, SD = 1.87 years; M years of practice = 2.66, SD = 1.07 years). In nine lab visits, we used visits 1 to 7 to familiarize participants with 3D-MOT, a subjective scale of mental fatigue, and a Stroop task involving mental set shifting. In the last two visits, participants performed in both experimental (EXP) and control (CON) conditions that were presented in randomized order. In the EXP condition, participants performed 3D-MOT pre- and post-60 minutes of induced mental fatigue; in the CON condition, they watched a documentary. After each condition, B participants performed the National Aeronautics and Space Administration Task Load Index (NASA-TLX). 3D-MOT performance measures were the "score" and "fastest trial score success." The response time on the Stroop tasks increased throughout the mental fatigue inducement in the experimental condition (p = .0037). The NASA-TLX responses were higher following the EXP condition than following the CON condition for mental demand, temporal demand, and performance (all ps < .05). Still, there were no significant EXP versus CON differences on the 3D-MOT performance indicators.

Assuntos

RESUMO

The present longitudinal meta-analysis aimed to estimate the growth curves and age at peak height velocity (PHV) in young male athletes, considering anthropometric data from available longitudinal studies. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, studies with repeated measurements in young male athletes were identified from searches across four databases (MEDLINE, SPORTDiscus, Web of Science, and SCOPUS). Estimations were based on multilevel polynomial models using a fully Bayesian framework. After a full-text screening of 317 studies meeting the eligibility criteria, 31 studies were considered. Studies were excluded mainly due to study design, repeated reporting, and incomplete reporting of the outcomes. Of the 31 studies analysed, 26 (84%) focused on young European athletes. The average age at PHV for the total sample of studies with young athletes was 13.1 years (90% credible interval: 12.9; 13.4). When considering data by sport, there was substantial variation in the age at PHV estimates (range: 12.4 to 13.5 years). As most studies in the meta-analysis focused on young European football players (52%), predictions for young athletes from other sports may be limited. The age at PHV in the available data occurred earlier than in general paediatric populations.

Assuntos

RESUMO

BACKGROUND: Among youth, plyometric-jump training (PJT) may provide a safe, accessible, and time-efficient training method. Less is known on PJT effectiveness according to the maturity status. OBJECTIVE: This systematic review with meta-analysis set out to analyse the body of peer-reviewed articles assessing the effects of PJT on measures of physical fitness [i.e., maximal dynamic strength; change of direction (COD) speed; linear sprint speed; horizontal and vertical jump performance; reactive strength index] and sport-specific performance (i.e., soccer ball kicking and dribbling velocity) according to the participants' maturity status. METHODS: Systematic searches were conducted in three electronic databases using the following inclusion criteria: (i) Population: healthy participants aged < 18 years; (ii) Intervention: PJT program including unilateral and/or bilateral jumps; (iii) Comparator: groups of different maturity status with control groups; (iv) Outcomes: at least one measure of physical fitness and/or sport-specific performance before and after PJT; (v) experimental design with an active or passive control group, and two or more maturity groups exposed to the same PJT. The DerSimonian and Laird random-effects models were used to compute the meta-analysis. The methodological quality of the studies was assessed using the PEDro checklist. GRADE was applied to assess certainty of evidence. RESULTS: From 11,028 initially identified studies across three electronic databases, 11 studies were finally eligible to be meta-analysed (n total = 744; seven studies recruited males; four studies recruited females). Three studies were rated as high quality (6 points), and eight studies were of moderate quality (5 points). Seven studies reported the maturity status using age at peak height velocity (PHV; pre-PHV values up to - 2.3; post-PHV up to 2.5). Another four studies used Tanner staging (from Tanner I to V). The training programmes ranged from 4 to 36 weeks, using 1-3 weekly training sessions. When compared to controls, pre-PHV and post-PHV participants obtained small-to-moderate improvements (ES = 0.35 - 0.80, all p < 0.05) in most outcomes (i.e., sport-specific performance; maximal dynamic strength; linear sprint; horizontal jump; reactive strength index) after PJT. The contrast of pre-PHV with post-PHV youth revealed that PJT was similarly effective in both maturity groups, in most outcome measures except for COD speed (in favour of pre-PHV). PJT induces similar physical fitness and sport-specific performance benefits in males and females, with a minimal exercise dosage of 4 weeks (8 intervention sessions), and 92 weekly jumps. Results of this meta-analysis are based on low study heterogeneity, and low to very low certainty of evidence (GRADE analysis) for all outcomes. CONCLUSION: Compared to control participants, PJT resulted in improved maximal dynamic strength, linear sprint speed, horizontal jump performance, reactive strength index, and sport-specific performance (i.e., soccer ball kicking and dribbling velocity). These effects seem to occur independently of the maturity status, as both pre-PHV and post-PHV participants achieved similar improvements after PJT interventions for most outcomes. However, several methodological issues (e.g., low sample sizes and the pooling of maturity categories) preclude the attainment of more robust recommendations at the current time. To address this issue, consistency in maturity status reporting strategies must be improved in future studies with the general youth population and youth athletes.

RESUMO

To investigate the presence of burnout syndrome in child athlete tryouts for the Brazilian Handball Team, before and after the National Development and Technical Improvement Camp is of great interest. A correlational study, with longitudinal design of the before-and-after type, carried out with 64 male athletes in the children's category, immersed in the National Camp for Development and Improvement of Handball Technique, in the municipality of São Bernardo do Campo, São Paulo, Brazil, in December 2018. To evaluate burnout syndrome, we used the Athlete Burnout Questionnaire (ABQ). There was a statistically significant increase of the mean scores for burnout and dimensions (Physical and Emotional Exhaustion = 1.5 to 1.6; p-value < 0.001; Reduced Sense of Accomplishment = 2.7 to 2.9; p-value < 0.001; Sports Devaluation = 1.4 to 1.6; p-value < 0.001; and General Burnout = 1.9 to 2.0; p-value < 0.001). The athletes selected for the national team had lower mean scores for general burnout and dimensions (Physical and Emotional Exhaustion = 1.5; Reduced Sense of Accomplishment = 2.7; Sports Devaluation = 1.5; General Burnout = 1.9). The National Camp for Development and Technical Improvement can have a negative impact on the mental health of athletes. This event is important to select the competitors with greater ability to face the pressure and adversities present in the sport environment.

Assuntos

RESUMO

Maximum isometric handgrip strength (MIHS) is a relevant parameter for judo performance and is related to health. Understanding the association between MIHS and MIHS relative (MIHSrel) and the absolute lean mass of the arm (LMarm) and the percentage of body fat (%BF) can provide important information for performance and health. The study aimed to investigate the correlation between MIHS and MIHSrel with the LMarm and the %BF of young judokas (sub-19, 15 males and 14 females). MIHS was measured using a multipurpose digital dynamometer with a load cell for computer. Body composition was measured by dual-energy X-ray absorptiometry (DXA). The correlation between MIHS, MIHSrel with LMarm and %BF was verified through Pearson's correlation, with a significance level of p < 0.05. Correlation between MIHSrel and %BF was very high only in female judokas for both arms (right, r = -0.76; left, r = -0.75). Correlations between LMarm and MIHS of the right and left arms ranged from very high to almost perfect for both sexes (r = 0.74 to 0.94). These results highlight the importance of strengthening the arms in young judokas, and controlling body fat for performance and health, especially in female judokas.

Assuntos

RESUMO

Abstract Background: Children and adolescents should be encouraged to participate in sports; however, physicians should screen for cardiac abnormalities that can lead to sudden death. The European Society of Cardiology, the Brazilian Society of Cardiology and the Brazilian Society of Sports Medicine indicate performing an electrocardiogram (ECG) in evaluating athletes, while the American Heart Association indicates complementary exams only when there is a personal or family history of cardiovascular diseases or changes in clinical examination. Objectives: To evaluate the need for an ECG in evaluating children and adolescents before starting physical activities. Methods: We recruited 983 children and adolescents who practiced physical activities for anthropometric assessment, clinical examination and conventional ECG at rest. Variables were analysed using the Goodman test with a significance level of 5%. Results: Participants had a higher incidence of overweight, obesity and severe obesity compared to standard World Health Organization (WHO) values. The most common finding in clinical examination was heart murmur (18.5% of participants). Electrocardiographic changes were found in 3.3% of participants, including paroxysmal supraventricular tachycardia and pre-excitation syndrome, which may be responsible for sudden death, even in asymptomatic individuals with no personal or family history of heart disease and no abnormality on clinical examination. Conclusions: ECG revealed arrhythmias that were not detected by clinical examination and may precede sudden death in individuals subjected to physical exertion, indicating its role in the assessment of children and adolescents before starting regular physical exercise.