Contextual variables affect peak running performance in elite soccer players: A brief report.

The current brief research report aimed to investigate the influence of contextual variables on peak running performance in male elite soccer players. We analyzed 29 matches of an elite soccer team during the Brazilian Serie A 2019. Twenty players were tracked using GPS units. Peak physical performance was determined using moving average running values with different time windows (1, 3, and 5-min periods). The variables analyzed were total distance covered, total distance covered in high-intensity running (≥19.8 km·h-1), and the distance in accelerations (≥2 m·s-2) and decelerations ( ≤-2 m·s-2). Four contextual variables were considered: 1) positional status; 2) match location; 3) match outcome; and 4) match status. Central defenders showed a lower 1-min peak total distance in relation to all other positions (p = 0.001-0.03). Peak physical performance was higher in away matches for high-intensity running, acceleration, and deceleration (p = 0.01-0.03). In matches that ended in losses, peak values for high-intensity running and acceleration were higher compared to draws and wins (p = 0.01-0.04). Regarding the match status, higher values were observed in draws than wins and losses (p = 0.01). Peak running performance vary according to contextual variables of the match in male elite soccer players. Positional differences were found for peak periods, and physical performance was higher in away matches.

Executive Functions, Physical Abilities, and Their Relationship with Tactical Performance in Young Soccer Players.

While tactical performance in soccer is associated with the players' and teams' collective actions in the context of game stimuli, how tactical performance relates to players' executive functions (EFs) and physical abilities should be examined. In this study, we examined these relationships among 81 Under-15 male soccer players who underwent tactical evaluation (FUT-SAT), EF tests (i.e.,(Stop-Signal Test and Design Fluency Test)), and physical tests (i.e.,(Maturity Offset, Yoyo Endurance Test II, Sargent Jump Test, and Sprint Test)). Multiple linear regression modeling with the stepwise method showed that approximately 48% of overall game tactical performance variance was explained by inhibitory control, biological maturation, and sprint capacity (p = .004; d = .54; r2 = .479), whereas 35% of offensive tactical performance variance was explained by the same dimensions (p = .001; d = .91; r2 = .353). In addition, approximately 28% of defensive tactical performance variance was explained by cognitive flexibility and aerobic resistance (p = .007; d = .39; r2 = .280). These results reflect the combined importance of EFs and physical abilities for tactical performance in young soccer players, suggesting that these abilities may be targets for training when trying to improve young players' performance.

Time to achieve steady state for an accurate assessment of resting energy expenditure in adolescents with healthy weight and obesity: A cross-sectional study

ABSTRACT Objective: The present study investigated the time needed to achieve a steady state for an accurate assessment of resting energy expenditure (REE) in adolescents with healthy weight and obesity. Materials and methods: Thirty adolescents aged 12-17 years were assigned to a group with healthy weight (GHW; n = 12, body mass index [BMI] 22.5 ± 3.6 kg/m2) and another group with obesity (GO; n = 18, BMI 34.1 ± 5.2 kg/m2). Participants underwent test-retest reliability of REE assessment as follows: a) 24 h of abstention from physical exercise, soft drinks, or caffeine; b) fasting for ~12 h; c) acclimation period of 10 min; d) 30-min assessment in a supine position. Results and discussion: A significant change occurred during the 30 min in REE. Significant differences existed between consecutive means until the 20th and 25th min for the GHW and GO, respectively. Although significant differences between trials 1 and 2 were detected during the first 5-10 min of assessment, the REE for each 5-min time point exhibited high test-retest reliability across trials in both groups (intraclass correlation coefficients range 0.79-0.99). Conclusion: The following recommendations are provided to promote accurate assessment of REE among adolescents: a) initiate the REE assessment with 10 min of acclimation to decrease restlessness; b) determine REE for a minimum of 20 min if healthy weight and 25 min if obesity; c) determine REE for a further 5 min, with the average of this last 5 min of REE data being regarded as the REE.

Time to achieve steady state for an accurate assessment of resting energy expenditure in adolescents with healthy weight and obesity: A cross-sectional study.

Objective: The present study investigated the time needed to achieve a steady state for an accurate assessment of resting energy expenditure (REE) in adolescents with healthy weight and obesity. Methods: Thirty adolescents aged 12-17 years were assigned to a group with healthy weight (GHW; n = 12, body mass index [BMI] 22.5 ± 3.6 kg/m2) and another group with obesity (GO; n = 18, BMI 34.1 ± 5.2 kg/m2). Participants underwent test-retest reliability of REE assessment as follows: a) 24 h of abstention from physical exercise, soft drinks, or caffeine; b) fasting for ~12 h; c) acclimation period of 10 min; d) 30-min assessment in a supine position. Results: A significant change occurred during the 30 min in REE. Significant differences existed between consecutive means until the 20th and 25th min for the GHW and GO, respectively. Although significant differences between trials 1 and 2 were detected during the first 5-10 min of assessment, the REE for each 5-min time point exhibited high test-retest reliability across trials in both groups (intraclass correlation coefficients range 0.79-0.99). Conclusion: The following recommendations are provided to promote accurate assessment of REE among adolescents: a) initiate the REE assessment with 10 min of acclimation to decrease restlessness; b) determine REE for a minimum of 20 min if healthy weight and 25 min if obesity; c) determine REE for a further 5 min, with the average of this last 5 min of REE data being regarded as the REE.

Contextual Variables Affect Running Performance in Professional Soccer Players: A Brief Report.

This study aimed to investigate the effects of contextual variables on running performance in Brazilian professional soccer players. Twenty male players from one club participating in the 1st Division of the Brazilian soccer championship were analyzed during 35 matches. Global Positioning System was used to determine total distance (TD) covered, distance covered and actions in high intensity and sprinting, and the number of accelerations, and decelerations. The independent variables used were match location, match outcome, opposition ranking, change of head coach, and distance traveled to play the matches. Total distance was higher in a way than home matches (9,712 vs. 9,533 m; p ≤ 0.05), and losses than draws and wins (9,846 vs. 9,400 vs. 9,551 m; p ≤ 0.05), whereas distance in sprinting was higher in draws than losses (203 vs. 175 m; p ≤ 0.01). Changing the head coach during the season resulted in overall lower distance covered in high intensity, sprinting, high-intensity actions (p ≤ 0.01), and decelerations (p ≤ 0.05). Higher values for distance covered in sprinting and high intensity were found in matches without travel compared to those with long-travel (p ≤ 0.05). Overall, running performance was affected by the location, match outcome, change of head coach, and distance traveled during the season.

Does Recreational Soccer Change Metabolic Syndrome Status in Obese Adolescents? A Pilot Study.

Purpose: To evaluate whether a soccer program (RSP) might lower risk factors related to metabolic syndrome (MetS) in obese adolescents. Methods: A 12-week randomized controlled trial [RSP: n = 6 (2 girls), age = 13.9 ± 1.6 yr, body mass index = 30.5 ± 2.1 kg/m2; Control: n = 7 (2 girls); age = 14.7 ± 2.3 yr, body mass index: 30.8 ± 3.1 kg/m2] was conducted. Participants underwent anthropometric, body fractioning, blood pressure, lipid profile, and glucose tolerance assessments at baseline and post-intervention. MetS status was determined based on waist circumference and at least two additional criteria: high blood pressure, hypertriglyceridemia, dyslipidemia, and hyperglycemia. RSP included eutrophic and overweight adolescents and consisted of small-sided games (85 ± 4% maximal heart rate) performed three times/week. Results: High-density lipoprotein increased [(HDL) ∆15.5 ± 5.2 mg·dL-1; p = .01] and triglycerides lowered [(TG) ∆-34.7 ± 7.1 mg·dL-1; p = .02] after RSP intervention. Between-group differences were also detected for changes in HDL (∆13.0 ± 6.1 mg·dL-1; p = .04) and TG (∆-47.1 ± 7.7 mg·dL-1; p = .05). The presence of MetS lowered in RSP (5 in 6 participants; p = .02), but not Control (1 in 7 participants; p = .32). Conclusion: A 12-week RSP was effective to reduce MetS risk factors and status in obese adolescents.

Respiratory muscle training in non-athletes and athletes with spinal cord injury: A systematic review of the effects on pulmonary function, respiratory muscle strength and endurance, and cardiorespiratory fitness based on the FITT principle of exercise prescription.

BACKGROUND: Respiratory muscle training (RMT) has been recommended to mitigate impacts of spinal cord injuries (SCI), but the optimal dosage in terms of the frequency, intensity, time, and type (FITT principle) to promote health in SCI individuals remains unclear. OBJECTIVE: To discuss research related to the effects of RMT on pulmonary function, respiratory muscle strength and cardiorespiratory fitness in athletes and non-athletes with SCI, presenting the FITT principle. METHODS: We performed a systematic review. PubMed, Lilacs, Scopus, Web of Science, PEDro, SciELO and Cochrane databases were searched between 1989 and August 2018. Participants were athletes and non-athletes with SCI. RESULTS: 4,354 studies were found, of which only 17 met the eligibility criteria. Results indicated that RMT is associated with beneficial changes in pulmonary function and respiratory muscle strength and endurance among athletes and non-athletes, whereas no effect was reported for maximal oxygen uptake. It was not possible to establish an optimal RMT dose from the FITT principle, but combined inspiratory/expiratory muscle training seems to promote greater respiratory changes than isolated IMT or EMT. CONCLUSION: The use of RMT elicits benefits in ventilatory variables of athletes and non-athletes with SCI. However, it remains unclear which RMT type and protocol should be used to maximize benefits.

Effect of small-sided games with manipulation of small targets on the perceived exertion and tactical and technical performance of college soccer players / Efeito de jogos reduzidos com manipulação de pequenos alvos sobre a percepção de esforço e o desempenho tático e técnico de jogadores de futebol universitário

Abstract The purpose of this study was to compare the tactical and technical performance and perceived exertion of college soccer players in small-sided games through the manipulation of small targets. Twenty players divided into four teams, played 5x5 games (25x20 m) with one and two small targets on different days. Games were divided into three four-minute times, with two-minute intervals between bouts. Perceived exertion and technical-tactical variables were evaluated using Ball Transmission Speed (ball received/ball contacts) and Team Sport Assessment Procedure (TSAP). TSAP generates performance indicators, such as: efficiency index, performance score, volume of play and ball attack. They are related to the actions of balls conquered, passes and finalizations. For statistical analysis, paired t test and Cohen's d effect size were performed to compare the two game configurations. Larger number of balls conquered with small target was verified (p<0.05; d=1.32), generating higher efficiency index and performance score. It was concluded that the perceived exertion is similar with one and two small targets and players recover more balls with only one small target. Through thisinformation, coaches can better handle this type of constraints according to the purpose of the training session.

Resumo O objetivo do estudo foi comparar o desempenho tático, técnico e a percepção subjetiva de esforço de jogadores de futebol universitário em jogos reduzidos através da manipulação de pequenos alvos. Vinte jogadores, divididos em quatro times, realizaram jogos de 5x5 (espaço:25x20 m) com um e com dois pequenos alvos, em diferentes dias. Os jogos foram divididos em três tempos de quatro minutos, com dois minutos de intervalo entre os tempos. Foi avaliada a percepção de esforço e variáveis técnico-táticas, utilizando a Velocidade de Transmissão da Bola (bolas recebidas/contatos na bola) e o Procedimento de Avaliação do Esporte em Equipe (TSAP). O TSAP gera indicadores de desempenho, como: índice de eficiência, escore de performance, volume de jogo e ataque com bola. Eles estão relacionados às ações de bolas conquistadas, passes e finalizações. Para análise estatística foi realizado teste t pareado e o tamanho do efeito d de Cohen para comparar as duas configurações de jogo. Foi verificada uma maior quantidade de bolas conquistadas com um pequeno alvo (p<0,05; d=1,32), gerando maior índice de eficiência e escore de performance. Conclui-se que a percepção de esforço é a mesma com um ou dois pequenos alvos e que um pequeno alvo faz com que os jogadores recuperem mais bolas. Através dessas informações o treinador pode manipular melhor este tipo de constrangimento de acordo com o objetivo da sua sessão de treino.

Relationship Between Percentages of Heart Rate Reserve and Oxygen Uptake Reserve During Cycling and Running: A Validation Study.

Guimarães, GC, Farinatti, PTV, Midgley, AW, Vasconcellos, F, Vigário, P, and Cunha, FA. Relationship between percentages of heart rate reserve and oxygen uptake reserve during cycling and running: a validation study. J Strength Cond Res 33(7): 1954-1962, 2019-This study investigated the relationship between percentages of heart rate reserve (%HRR) and oxygen uptake reserve (%VO2R) during a cardiopulmonary exercise test (CPET) and discrete bouts of isocaloric cycling and treadmill running. Thirty men visited the laboratory 3 times for anthropometrical and resting VO2 assessments, and perform cycling and running CPETs. Ten men visited the laboratory twice more to investigate the validity of the %HRR-%VO2R relationships during isocaloric bouts of cycling and running at 75% VO2R with energy expenditures of 400 kcals. The %HRR was significantly higher than the %VO2R during both CPETs at all exercise intensities (p < 0.001). During isocaloric exercise bouts, mean %HRR-%VO2R differences of 6.5% and 7.0% were observed for cycling and running, respectively (p = 0.007-p < 0.001). The %HRR and %VO2R increased over time (p < 0.001), the rate of which was influenced by exercise modality (p < 0.001). On average, heart rate was 5 (p = 0.007) and 8 (p < 0.001) b·min higher than predicted from the second energy expenditure quartile for cycling and running, respectively; however, observed VO2 was lower than predicted during all quartiles for cycling, and the first quartile for running. Consequently, time to achieve the target energy expenditure was greater than predicted (p < 0.01). In conclusion, the %HRR-%VO2R relationship observed during CPET data did not accurately transpose to prolonged isocaloric bouts of cycling and running. In addition, power outputs and speeds defined by the American College of Sports Medicine equations for cycling and running, respectively, overestimated VO2 and energy expenditure.

Analysis of the Effectiveness of Long Distance Passes in 2014 Brazil FIFA World Cup / Análise da Eficácia dos passes de longa distância na Copa do Mundo FIFA Brasil 2014

Abstract The aim of this study was to analyze the effectiveness of long distance passes performed during the 2014 Brazil FIFA World Cup. All 64 matches were analyzed, however, actions performed during overtime were not included in the sample. The study defined long pass as an action made by a player from the defensive midfield aiming at passing the ball to another teammate located on the offensive field. The action result assessment followed these criteria: shots on goal, ball possession maintenance, loss of ball possession and ball possession recovery. Total long distance passes were also considered in the analysis. Throughout the tournament, 4,512 long distance passes were attempted. The main findings were that 59% resulted on loss, 28% on maintenance and 12% on recovery of the ball possession, but only less than 1% resulted in shots on goal (F = 505.5; p<0.001; partial ƞ2 = 0.76). Teams with the highest number of long pass attempts loose ball possession more frequently. There were more long distance passes at the first and at the last 15 min of matches. UEFA and Concacaf teams executed, respectively, the lowest and the highest number of long passes. The major outcome of this study is that long distance passes have low effectiveness due to the high rate of loss of ball possession, rarely creating score opportunities. The more the teams executed long passes, the more the teams lose ball possession.

Resumo Objetivou-se analisar a eficácia dos passes de longa distância realizados durante os jogos da Copa do Mundo da FIFA 2014. Todas as 64 partidas foram analisadas. Porém, as prorrogações na fase eliminatória da competição não foram acrescidas na amostra. O estudo definiu o lançamento como uma ação feita por um jogador do meio campo defensivo com o objetivo de passar a bola para outro colega de equipe localizado no campo ofensivo. O resultado da ação foi avaliado com base nos seguintes critérios: finalização ao gol, manutenção da posse de bola, perda da posse de bola e recuperação da posse de bola. O total dos lançamentos também foi considerado nas análises. Ao longo do torneio houve 4.512 lançamentos. Os principais achados foram que 59% dos lançamentos resultaram em perda, 28% em manutenção e 12% em recuperação da posse da bola, mas apenas menos de 1% resultaram em finalização ao gol (F = 505,5; p <0,001 Parcial ƞ2 = 0,76). Equipes que lançaram mais perderam a bola com maior frequência. Houve mais lançamentos nos primeiros e nos últimos 15 min de jogo. Equipes da UEFA e da Concacaf executaram, respectivamente, o mais baixo e o mais alto número de lançamentos. O principal achado deste estudo é que os lançamentos apresentam baixa eficácia devido à alta taxa de perda da posse de bola, raramente criando oportunidades de finalização à meta. Quanto mais lançamentos feitos, mais posse de bola perdida.

Standardized MET Value Underestimates the Energy Cost of Treadmill Running in Men.

The main purpose of the present study was to compare the reference metabolic equivalent (MET) value and observed resting oxygen uptake (VO2) for defining cardiorespiratory fitness (VO2max) and characterizing the energy cost of treadmill running. A heterogeneous cohort of 114 healthy men volunteered to participate. In Part 1 of the study, 114 men [mean±SD, age: 24±5 years; height: 177.1±7.9 cm; body mass: 75.0±10.0 kg] visited the laboratory twice for assessment of resting and maximal VO2 values to compare the reference MET value vs. observed resting VO2 and to investigate the association between resting VO2 and VO2max. In Part 2, 14 of the 114 men visited the laboratory once more to perform a 30-min bout of running at 8.0 km∙h-1/8.3 METs. The mean observed resting VO2 of 3.26 mL·kg-1·min-1 was lower than the reference MET value of 3.5 mL·kg-1·min-1 (P<0.001). Resting and maximal VO2 values relative to total body mass and fat-free mass were positively correlated (R=0.71 and 0.60, respectively; P<0.001). The maximal MET and energy cost of treadmill running were consequently underestimated when calculated using the reference MET value only for those with low VO2max (P=0.005 to P<0.001). In conclusion, the reference MET value considerably overestimated observed resting VO2 in men with low VO2max, resulting in underestimations of the maximal MET, exercise intensity prescription, and the energy cost of running.

Performance and tactical behavior of youth soccer players / Desempenho e comportamento tático de jogadores de futebol das categorias de base

Abstract The aim of this research was to evaluate the performance and tactical behavior of youth soccer players of teams from base categories. The sample consisted of 152 male soccer players aged 11-17 years who participated in the in the U-13 (n = 50), U-15 (n = 62) and U-17 (n = 40) Sergipe State Championship in the year 2015. The System of Tactical Assessment in Soccer (FUT-SAT) was used to identify the players’ tactical behavior based on the fundamental tactical principles. The main results of the study show that players presented higher tactical offensive performance (50.8 ± 9.8 points) compared to defensive performance (34.3 ± 5.7 points) (p < 0.001; d = 2,1), and the Depth Mobility principle presented the highest performance indices in the offensive phase (64.1 ± 8.7; F = 54.4; p < 0.001; partial ƞ2 = 0.26). Defensive Coverage showed the highest performance indexes in the defensive phase (46.1 ± 24.3; F = 54.4; p < 0.001; partial ƞ2 = 0.26).

Resumo O objetivo da pesquisa foi avaliar o desempenho e o comportamento tático de jovens jogadores de futebol de equipes das categorias de base. A amostra foi composta por 152 jogadores de futebol, do sexo masculino, entre 11 e 17 anos de idade, que participaram do Campeonato Sergipano nas categorias sub-13 (n = 50), sub-15 (n = 62) e sub-17 (n = 40) no ano de 2015. Foi utilizado o Sistema de Avaliação Tática no Futebol (FUT-SAT) para identificar o comportamento tático dos jogadores a partir dos princípios táticos fundamentais do futebol. Os principais resultados do estudo mostraram que os jogadores apresentaram maior performance tática ofensiva (50,8 ± 9,8 pontos) do que a defensiva (34,3 ± 5,7 pontos) (p < 0,001; d = 2,1), sendo que o princípio da Mobilidade foi o que apresentou os maiores índices de performance na fase ofensiva (64,1 ± 8,7; F = 54,4; p < 0,001; ƞ2 parcial = 0,26). A Cobertura Defensiva foi o princípio que apresentou os maiores índices de performance na fase defensiva (46,1 ± 24,3; F = 54,4; p < 0,001; ƞ2 parcial = 0,26).

O futebol recreativo como uma nova abordagem terapêutica para a obesidade em crianças e adolescentes: uma revisão sistemática / Recreational soccer as a novel therapeutic approach to children and adolescent obesity: a systematic review

O aumento da prevalência de sobrepeso e obesidade tem se tornado um grave problema de saúde pública. No Brasil dados recentes sugerem que o sobrepeso atinge mais de 30% das crianças entre os cinco e os nove anos de idade e cerca de 20% da população entre os 10 e os 19 anos. A atividade física é considerada uma importante ferramenta para a prevenção e tratamento da obesidade infantil. O futebol, um dos desportos mais populares no mundo, tem sido considerado uma abordagem importante e eficaz para a promoção da saúde através da atividade física. O objetivo do presente estudo foi revisar o estado atual do conhecimento sobre a influência de programas de futebol recreativo (PFR) na prevenção e tratamento da obesidade e suas comorbidades associadas em crianças e adolescentes. Uma extensa pesquisa em bases de dados eletrônicas online foi realizada na Medline, ScienceDirect, LILACS, Scholar Google, Scopus e SPORTDiscus. Nove estudos preencheram todos os critérios de inclusão, com um total de 214 participantes que completaram seus respectivos programas de futebol recreativo. Embora um pequeno número de estudos tenha sido encontrado, os resultados reportados sugerem que a participação nos PFR pode melhorar a composição corporal, fatores de risco metabólicos e variáveis do bem-estar psicológico de crianças com sobrepeso e obesidade. Encontramos evidências de que a prática do futebol recreativo pode representar uma opção eficaz e acessível para a prevenção e tratamento da obesidade e suas comorbilidades associadas em crianças e adolescentes.

The raising level of overweight and obesity prevalence has become a serious public health problem. Recent Brazilian data suggest that overweight accounts for 30% of all children from five to nine years old and around 20% of the 10 to 19 population. Physical activity is considered an important tool for the prevention and treatment of child obesity. And soccer, one of the most popular sports in the world, has being considered and important and effective approach to promote health through physical activity, being yet of easy implementation and low investment. The objective of the present study was to review the current state of knowledge about the influence of recreational soccer programs (RSP) in the prevention and treatment of child and adolescent obesity and its associated comorbidities. An extensive search of online electronic databases was held in Medline, ScienceDirect, LILACS, Google Scholar, Scopus, and SPORTDiscus. Nine studies met all inclusion criteria for this review, with a total of 214 participants completing their respective recreational soccer program. Despite the low number of studies found, the reported results suggest that RSP's can improve the body composition profile, metabolic risk factors and psychological well-being variables of overweight and obese children. We found evidences that the practice of recreational soccer may represent an effective and available option to the prevention and treatment of obesity and it associated comorbidities in children and adolescents.

Health markers in obese adolescents improved by a 12-week recreational soccer program: a randomised controlled trial.

The effects of a recreational soccer program (RSP) upon body composition, heart rate variability (HRV), biochemical markers, cardio-respiratory fitness, and endothelial function in obese adolescents were investigated. A randomised controlled clinical trial was conducted with 30 adolescents aged 12-17 years and body mass index (BMI) >2 standard deviations of WHO reference values, which were assigned to RSP (n = 10, 2 girls) and obese control (n = 10, 4 girls) groups. The 12-week RSP included 60-min sessions performed 3 times/week. BMI, waist circumference, blood pressure, blood glucose, lipid profile, insulin, C-reactive protein, HRV, and maximal oxygen consumption (VO2peak) were evaluated following standardised procedures. Body composition was determined by dual-energy X-ray absorptiometry and endothelial function by venous occlusion plethysmography. After intervention, RSP exhibited significant reductions in BMI (-0.7 ± 0.2 kg · m(-2)), waist circumference (-8.2 ± 1.4 cm), %body fat (-2.2 ± 0.4%), systolic blood pressure (-5.0 ± 2.3 mmHg), total cholesterol (-16.2 ± 5.8 mg · dL(-1)), triglycerides (-20.5 ± 12.9 mg · dL(-1)), C-reactive protein (-0.06 ± 0.01 mg · dL(-1)), insulin resistance (HOMA-IR, -1.4 ± 0.6), and sympathetic activity (LF, -13.9 ± 6.6 un) vs. controls (P < 0.05). Significant increase was observed in parasympathetic activity (HF, 13.9 ± 6.6 un), VO2peak (7.9 ± 2.8 ml · kg(-1) · min(-1)), and high-density lipoprotein cholesterol (11.0 ± 6.3 mg · dL(-1)) (P < 0.05). Vascular conductance (19.5 ± 8.1 ml · min(-1) · 100 ml, P = 0.005) increased and vascular resistance (-5.9 ± 2.4 ml · min(-1) · 100 ml, P = 0.041) decreased in RSP, but not in controls. A 12-week recreational soccer intervention was effective to improve biochemical, cardiovascular, and fitness health markers in obese adolescents.

Heart rate variability assessment with fingertip photoplethysmography and polar RS800cx as compared with electrocardiography in obese adolescents.

AIM: This study investigated the accuracy and reliability of short-term resting heart rate variability (HRV) assessment by fingertip photoplethysmography (PPG) and using a cardiofrequencimeter (Polar RS800cx) in obese adolescents. Obesity in adolescents may be related to autonomic dysfunction due to insulin resistance and/or increased central fat. This fact may affect the accuracy and reliability of the evaluation of autonomic activity at rest. METHODS: Fourteen adolescents (15±2 years) classified as obese and exhibiting insulin resistance underwent the following procedures: (a) anthropometric measurements, and (b) two 25-min HRV recordings in a supine position conducted simultaneously using ECG, PPG, and Polar RS800cx. RESULTS: The results showed significant correlations between HRV markers obtained using Polar RS800cx and PPG and those obtained from ECG, with coefficients of determination (R) and intraclass correlation coefficients ranging from 0.60 to 0.98 (P-value ranging from 0.03 to 0.05) and 0.70 to 0.99 (P-value ranging from 0.01 to 0.05), respectively. The technical error of measurement and intraclass correlation coefficients for test-retest reliability ranged from 8.9 to 45.8% and 0.38 to 0.68 for ECG, 8.0 to 30.5% and 0.29 to 0.61 for Polar RS800cx, and 7.2 to 54.6% and 0.45 to 0.64 for PPG, respectively. CONCLUSION: HRV indices calculated by Polar RS800cx and PPG appear to be as accurate and reproducible as data from ECG when evaluating the autonomic control of heart rate at rest in obese adolescents.

Short-term performance effects of three different low-volume strength-training programmes in college male soccer players.

This study aimed to analyse the short-term performance effects of three in-season low-volume strength-training programmes in college male soccer players. Fifty-seven male college soccer players (age: 20.3±1.6 years) were randomly assigned to a resistance-training group (n=12), plyometric training group (n=12), complex training group (n=12), or a control group (n=21). In the mid-season, players underwent a 9-week strength-training programme, with two 20 min training sessions per week. Short-term effects on strength, sprint, agility, and vertical jump abilities were measured. All training groups increased 1-RM squat (range, 17.2-24.2%), plantar flexion (29.1-39.6%), and knee extension (0.5-22.2%) strength compared with the control group (p<0.05). The resistance-training group increased concentric peak torque of the knee extensor muscles by 9.9-13.7%, and changes were greater compared with the control group (p<0.05). The complex training group presented major increments (11.7%) in eccentric peak torque of the knee flexor muscles on the non-dominant limb compared with the control group and plyometric training group (p<0.05). All training groups improved 20-m sprint performance by 4.6-6.2% (p<0.001) compared with the control group. No differences were observed in 5-m sprint and agility performances (p>0.05). Overall, the results suggest that in-season low-volume strength training is adequate for developing strength and speed in soccer players.

Physical activity in overweight and obese adolescents: systematic review of the effects on physical fitness components and cardiovascular risk factors.

BACKGROUND: The increasing prevalence of obesity in the pediatric age range has become a major concern. Studies have investigated the role of physical activity (PA) to prevent obesity in this population. However, previous reviews did not focus on the effects of PA in overweight/obese adolescents on physical fitness and risk factors for cardiovascular disease altogether. OBJECTIVE: The present systematic review analyzed trials investigating the effect of PA on aerobic capacity, muscle strength, body composition, hemodynamic variables, biochemical markers, and endothelial function in obese/overweight adolescents. METHODS: PubMed, LILACS, Web of Science, Scopus (including Embase), and SPORTDiscus databases were searched for relevant reports without time limits. Inclusion criteria included studies published in English, with overweight and obese adolescents aged 12-17 years. The review was registered (Number CRD42013004632) on PROSPERO, the International Prospective Register of Systematic Reviews. RESULTS: The results indicated that PA is associated with significant and beneficial changes in fat percentage, waist circumference, systolic blood pressure, insulin, low-density lipoprotein cholesterol, and total cholesterol, as well as with small non-significant changes in diastolic blood pressure, glucose, and high-density lipoprotein cholesterol. CONCLUSION: Although limited, results from controlled trials suggest that PA intervention may improve physical fitness and risk factors for cardiovascular disease in adolescents who are overweight or obese.

Validity and reproducibility of the sargent jump test in the assessment of explosive strength in soccer players.

The purpose of this study was to check the validity and the intra- and inter-evaluators reproducibility of the Sargent Jump Test, as an instrument of explosive strength measurement of soccer players of the sub-15 class. Forty-five soccer players were randomly selected from different clubs competing in the local soccer championship. All subjects performed one test on the same jump platform model Jumptest(®) (Hidrofit Ltda, Brazil) and two independent Sargent Jump Tests assessed by the same evaluator. Two days later, another Sargent Jump Test was performed simultaneously assessed by 2 evaluators. In all tests, three jumps were performed and the highest one was registered. In order to check the validity, the first Sargent Jump Test results were compared to those from the jump platform, considered the gold standard. To evaluate intra- and inter-evaluator reproducibility, results from the first, second and third Sargent Jump Tests were analyzed. The validity and reproducibility were evaluated by intraclass correlation coefficients (ICC), and by the Bland and Altman test (statistical pack SPSS 11.0), with a significance level set at p<0.05. The values found for validity (r=0.99, p=0.001), for intra-evaluator reproducibility (r=0.99, p=0.001) and for inter-evaluator reproducibility (r=1.0, p=0.001), permitted us to conclude that the Sargent Jump Test is a valid and reproducible instrument for measuring the explosive strength in homogeneous groups, such as those used in the present study.

Validade e Fidedignidade do Sargent Jump Test na Avaliação da Força Explosiva de Jogadores de Futebol / Validity and Reliabilty of the Sargent Jump Test in Assessing the Explosive Strength of Soccer Players

O objetivo deste estudo foi verificar a validade e afidedignidade intradia e interdias do Sargent Jump Test, comoinstrumento de medida da força explosiva de atletas de futebolda categoria sub-15. Material e Métodos: Foram avaliados45 jogadores dos clubes que disputam o campeonato cariocade futebol, escolhidos aleatoriamente, que executaram umteste numa plataforma de saltos, e dois Sargent Jump Tests,todos no mesmo dia, e mais um Sargent Jump Test 48 horasapós. Em todos os testes foram executados três saltos esomente o maior deles foi computado. Para avaliar a validadeforam utilizados os resultados dos saltos na plataforma e doprimeiro Sargent Jump Test. Para avaliar a fidedignidadeintradia foram utilizados os resultados do primeiro e segundoSargent Jump Test e para avaliar a fidedignidade interdias,os resultados do primeiro e do terceiro Sargent Jump Test.Para análise da normalidade dos dados foi utilizado o testede Kolmogorov-Smirvov. Resultados: A validade e a fidedignidadeforam dadas através do coeficiente de correlaçãointerclasses e do teste de Bland e Altman, do software SPSS11, com nível de significância p<0,05. Observou-se: validade(r=0,99, p=0,001), fidedignidade intradia (r=0,99, p=0,001),e fidedignidade interdias (r=0,97, p=0,001). Conclusão: Estesresultados permitem afirmar que o Sargent Jump Testconstitui-se num instrumento útil e válido para avaliação daforça explosiva...

Objective: The aim of the this study was to check the validityand the intra and interday reliability of the Sargent Jump Test,as an instrument to measure the explosive strength of sub-15 soccer players. Materials and Methods: Forty-five soccerplayers from clubs which dispute the Carioca Championship,randomly selected, performed one test in a Jump Platformand two Sargent Jump Tests, all in the same day and anotherSargent Jump Test 48 hours later. In all tests they performedthree jumps and only the highest one was computed. Toassess the validity there were used the results from theJump Platform and from the first Sargent Jump Test. To assessthe intraday reliability, there were used the results from thefirst and the second Sargent Jump Test and to assess theinterday reliability, the results of the first and the third SargentJump Test. To analyze normality of the data it was used theKolmogorov-Smirvov test. The validity and reliability weregiven through the interclass correlation coefficient andthrough the Bland-Altman test, from the SPSS 11 software,with a significance level of p<0,05. Results: It was noted:validity (r=0,99, p=0,001), intraday reliability (r=0,99, p=0,001),and interday reliability (r=0,97, p=0,001). Conclusion: Theseresults indicate that the Sargent Jump Test constitutes a usefuland valid instrument to assess the explosive strength...