Resisted Sprint Velocity in Female Soccer Players: Influence of Physical Capacities.

This study aimed to examine the effects of different sled overloads on maximum sprint velocity achieved by female soccer players with different strength, speed, and power levels. Twenty elite female soccer players from the same club participated. On the same day, athletes performed: linear and resisted-sprint tests with 30 and 60 % of body-mass over 5-, 10-, and 20-m; half-squat maximum bar-power output, and half-squat one-repetition maximum assessment. A median split analysis was used to divide players into two groups according to their velocity, half-squat one-repetition maximum, and half-squat power. Differences in percentage decreases between unresisted- and resisted-sprints comparing higher and lower groups were analyzed using magnitude-based inferences. Overall, the stronger, faster, and more powerful players were less affected by both loads, as demonstrated by their lower decreases in velocity over the different distances. However, half-squat power appeared to be more sensitive for indicating impairments in resisted-sprint performance, due to meaningful differences in percentage decreases observed between higher and lower power groups. Notably, overloads of 30 and 60% of body-mass provoked substantial reductions in resisted-sprint velocity (~22.9% for 30% and ~51.4% for 60% of body-mass, relative to unresisted-sprint velocity). Athletes with superior power levels are less affected by the progressive sled overloading.

Short-Term Cardiac Autonomic Recovery after a Repeated Sprint Test in Young Soccer Players.

The aim of this study was to describe the time course (within 2 h post-exercise) of heart rate variability (HRV) recovery following a traditional repeated sprint ability (RSA) test applied to youth soccer players. Twenty-four young soccer players (18.4 ± 0.5 years) undertook the following assessments: (1) 10 min rest in the seated position for HRV assessment; (2) a repeated sprint ability (RSA) test; (3) passive recovery in the seated position for 10 min, immediately after finishing the RSA test and 1 h and 2 h post-RSA test. During the HRV measurements (using the natural log of root mean square difference of successive normal RR intervals-lnRMSSD) the participants were instructed to assume a comfortable sitting position, remaining awake and breathing spontaneously for 10 min. Magnitude-based inference was used in the analyses. After the RSA test, the post-1 h measure was almost certainly lower than the resting measure, but almost certainly higher than the lnRMSSD measured post-RSA test. The lnRMSSD post-2 h was likely lower than the resting lnRMSSD and very likely higher than post-1 h. In conclusion, lnRMSSD is severely depressed after performing an RSA test, and reactivation is incomplete after 2 h of passive recovery. This result should be considered by practitioners when applying successive training sessions within intervals shorter than 2 h.

Vertically and horizontally directed muscle power exercises: Relationships with top-level sprint performance.

The capacity to rapidly generate and apply a great amount of force seems to play a key role in sprint running. However, it has recently been shown that, for sprinters, the technical ability to effectively orient the force onto the ground is more important than its total amount. The force-vector theory has been proposed to guide coaches in selecting the most adequate exercises to comprehensively develop the neuromechanical qualities related to the distinct phases of sprinting. This study aimed to compare the relationships between vertically-directed (loaded and unloaded vertical jumps, and half-squat) and horizontally-directed (hip-thrust) exercises and the sprint performance of top-level track and field athletes. Sixteen sprinters and jumpers (including three Olympic athletes) executed vertical jumps, loaded jump squats and hip-thrusts, and sprinting speed tests at 10-, 20-, 40-, 60-, 100-, and 150-m. Results indicated that the hip-thrust is more associated with the maximum acceleration phase (i.e., from zero to 10-m; r = 0.93), whereas the loaded and unloaded vertical jumps seem to be more related to top-speed phases (i.e., distances superior to 40-m; r varying from 0.88 to 0.96). These findings reinforce the mechanical concepts supporting the force-vector theory, and provide coaches and sport scientists with valuable information about the potential use and benefits of using vertically- or horizontally-based training exercises.

Perceived training load and jumping responses following nine weeks of a competitive period in young female basketball players.

The aims of this study were to describe the session rating of perceived exertion (sRPE), total quality recovery (TQR), and variations in countermovement jump (CMJ) height throughout nine weeks of a competitive period in young female basketball players. In total, 10 young female basketball players (17.2 ± 0.4 years; 71.8 ± 15.0 kg; 177.2 ± 9.5 cm) participated in this study. The sRPE and TQR were assessed in each training session, whereas the CMJ height was assessed prior to the first weekly training session. The magnitude-based inferences method was used to compare the sRPE, TQR, and CMJ height across the nine weeks of training. The training loads accumulated in weeks 1, 2, and 3 were likely to almost certainly be higher than in the following weeks (ES varying from 0.67 to 2.55). The CMJ height in week 1 was very likely to be lower than in weeks 2, 5, 7, and 8 (ES varying from 0.24 to 0.34), while the CMJ height of the 9th week was likely to almost certainly be higher than all previous weeks of training (ES varying from 0.70 to 1.10). Accordingly, it was observed that when higher training loads were accumulated, both CMJ and TQR presented lower values than those presented during periods with lower internal training loads. These results highlight the importance of using a comprehensive and multivariate approach to effectively monitor the physical performance of young athletes.

Functional Screening Tests: Interrelationships and Ability to Predict Vertical Jump Performance.

There are several methods used in sports science to identify asymmetries in athletes, given their purported relevance to injury prevention and performance optimization. We aimed to verify whether asymmetries provided by isokinetic assessments, jump tests, and tensiomyography (TMG) are associated with each other, and whether their respective functional indices are related to jumping ability. TMG parameters, unilateral and bilateral squat-jump (SJ) and countermovement-jump (CMJ) performances, and peak torque in knee-extension and flexion with angular velocities of 60o/s and 300o/s for twenty-four soccer players were retained for analyses. Asymmetry was detected by examining the percentage difference between dominant and non-dominant legs. The median-split technique was used to identify the best and worst performers in SJ and CMJ tests. Results revealed that the asymmetries detected in the three different methods were not interrelated. Curiously, better performances in SJ and CMJ tests were associated with higher asymmetry levels. Furthermore, only the knee-extension peak torque at both angular velocities was correlated moderately to largely (r=0.48-0.66) with jump performance. Despite their recognized ability to predict the risk of injury, the absence of interrelationships between TMG, isokinetic tests, and unilateral jumps precludes their single use as a unique functional screening diagnostic. Finally, and very importantly, lower-limb asymmetry is not necessarily related to impaired vertical jump performance in soccer players.

Loaded and unloaded jump performance of top-level volleyball players from different age categories.

The aim of this study was to investigate the differences in loaded and unloaded jump performances between different age categories of top-level volleyball players from the same club. Forty-three volleyball players were divided into four age groups: under-17, under-19, under-21 and professional. Vertical jumping height for squat jump (SJ), countermovement jump (CMJ) and CMJ with arm swing (CMJa) and mean propulsive velocity (MPV) in the loaded jump squat exercise with 40% of the athlete's body mass were compared among the different age categories, considering body mass as a covariate. SJ and CMJ jump height values were higher for professional and under-21 players than under-17 players (p<0.05). CMJa height was higher for under-21 players than under-19 and under-17 players (p<0.05). MPV in the loaded jump squat was higher for under-21 players than under-17 players (p<0.05). From a general perspective, these results suggest that aging per se is not capable of substantially improving loaded and unloaded vertical jump performances across different age categories of top-level volleyball players. Therefore, to increase the vertical jumping ability of these team sport athletes throughout their long-term development, coaches and strength and conditioning professionals are encouraged to implement consistent neuromuscular training strategies, in accordance with the specific needs and physiological characteristics of each age group.

Movement Patterns of a U-20 National Women's Soccer Team during Competitive Matches: Influence of Playing Position and Performance in the First Half.

The aim of this study was to determine the match locomotor characteristics of a sample of U-20 Brazilian female soccer players. Seven international matches were analyzed during the 2015 U-20 South American Championship, using global positioning technology. During a typical match, fullbacks and forwards covered greater distances in high-intensity running and sprinting than central defenders and midfielders (effect size [ES]=1.42-3.69). In the final 15 min of a game, total and high-intensity running distance and player load were ≈20 to 35% (ES=0.41-3.86) lower than in the first 15 min period for midfielders, fullbacks, forwards, and central defenders. Sprinting, and high-intensity running distances, and the frequency of accelerations >2 m.s-2 immediately after the most intense 5-min period declined in forwards (ES=1.78-2.67), fullbacks (ES=1.96-5.25), midfielders (ES=1.66-3.77), and central defenders (ES=1.50-4.22). Maintaining 'high' levels of activity in the first half resulted in ≈19% reductions in the second half for sprinting distance and frequency of accelerations >2 m.s-2 (ES=0.43 and 0.88), while increases in these locomotor activities were observed in situations with 'low' levels of activity (ES=0.64 and 1.12, for sprinting and accelerations >2 m.s-2, respectively) (within-subject analysis). The data demonstrate that high-intensity efforts are reduced during various phases of international matches and overall activity patterns vary among playing positions. This information could be useful in the development and prescription of sex- and age-specific training regimes.

Bar velocities capable of optimising the muscle power in strength-power exercises.

This study aimed at testing whether there are mean propulsive velocities (MPVs) capable of maximising the mean propulsive power (MPP) during the execution of bench press (BP), bench throw (BT), half squat (HS) and jump squat (JS). Additionally, we assessed the differences in MPP/MPV between ballistic and traditional exercises. Seventeen male rugby sevens players performed MPP tests in BP, BT, HS and JS and maximum isometric force (MIF) tests in HS and BP. The JS presented higher MPP (977.4 ± 156.2 W) than the HS (897.9 ± 157.7 W) (P < 0.05); the BP (743.4 ± 100.1 W) presented higher MPP than the BT (697.8 ± 70.4 W) (P < 0.05). Ballistic exercises presented higher optimum MPV (JS = 1.02 ± 0.07 m·s-1; BT = 1.67 ± 0.15 m·s-1) than traditional exercises (HS = 0.93 ± 0.08 m·s-1; BP = 1.40 ± 0.13 m·s-1) (P < 0.05). The optimum MPP in the JS, BT, HS and BP occurred at 28.2 ± 5.79, 23.3 ± 4.24, 32.4 ± 9.46 and 27.7 ± 5.33% of the MIF, respectively. The coefficient of variation (CV) of MPV at optimum MPP ranged from 7.4% to 9.7%, while the CV of %MIF ranged from 18.2% to 29.2%. The MPV is a more precise indicator of the optimum loads than the percentages of MIF due to its low inter-subject variability as expressed by CV. Therefore, MPV can be used to determine the optimum power load in the four investigated exercises.

Improving Sprint Performance in Soccer: Effectiveness of Jump Squat and Olympic Push Press Exercises.

Training at the optimum power load (OPL) is an effective way to improve neuromuscular abilities of highly trained athletes. The purpose of this study was to test the effects of training using the jump squat (JS) or Olympic push-press (OPP) exercises at the OPL during a short-term preseason on speed-power related abilities in high-level under-20 soccer players. The players were divided into two training groups: JS group (JSG) and OPP group (OPPG). Both groups undertook 12 power-oriented sessions, using solely JS or OPP exercises. Pre- and post-6 weeks of training, athletes performed squat jump (SJ), countermovement jump (CMJ), sprinting speed (5, 10, 20 and 30 m), change of direction (COD) and speed tests. To calculate the transfer effect coefficient (TEC) between JS and MPP OPP and the speed in 5, 10, 20, and 30 m, the ratio between the result gain (effect size [ES]) in the untrained exercise and result gain in the trained exercise was calculated. Magnitude based inference and ES were used to test the meaningful effects. The TEC between JS and VEL 5, 10, 20, and 30 m ranged from 0.77 to 1.29, while the only TEC which could be calculated between OPP and VEL 5 was rather low (0.2). In addition, the training effects of JS on jumping and speed related abilities were superior (ES ranging from small to large) to those caused by OPP (trivial ES). To conclude, the JS exercise is superior to the OPP for improving speed-power abilities in elite young soccer players.

Determining the Optimum Power Load in Jump Squat Using the Mean Propulsive Velocity.

The jump squat is one of the exercises most frequently used to improve lower body power production, which influences sports performance. However, the traditional determination of the specific workload at which power production is maximized (i.e., optimum power load) is time-consuming and requires one-repetition maximum tests. Therefore, the aim of this study was to verify whether elite athletes from different sports would produce maximum mean propulsive power values at a narrow range of mean propulsive velocities, resulting in similar jump heights. One hundred and nine elite athletes from several individual/team sport disciplines underwent repetitions at maximal velocity with progressive loads, starting at 40% of their body mass with increments of 10% to determine the individual optimum power zone. Results indicated that regardless of sport discipline, the athletes' optimum mean propulsive power was achieved at a mean propulsive velocity close to 1.0 m.s(-1) (1.01 ± 0.07 m.s(-1)) and at a jump height close to 20 cm (20.47 ± 1.42 cm). Data were narrowly scattered around these values. Therefore, jump squat optimum power load can be determined simply by means of mean propulsive velocity or jump height determination in training/testing settings, allowing it to be implemented quickly in strength/power training.

Pre-competitive physical training and markers of performance, stress and recovery in young volleyball athletes / Treinamento físico pré-competitivo e marcadores de desempenho, estresse e recuperação em jovens atletas de voleibol

The aim of this study was to analyze the effect of physical training during a pre-competition period on power and explosive strength endurance of the lower limbs, stress and recovery in young volleyball athletes. Seven male athletes (15.8 ± 0.5 years, 186.1 ± 6.6 cm, 75.9 ± 1.8 kg) of an Under-16 volleyball team were trained during a pre-competition period of 4 weeks. The internal training load (ITL) was monitored by the session RPE method. The participants performed a countermovement jump test (CMJ) and an intermittent jump test of four sets of 15 seconds (IJT) on the first day of training (baseline) and on the last day of the 2nd (post-week 2) and 4th week (post-week 4). The RESTQ-Sport Questionnaire was applied at baseline and on the last day of the 2nd, 3rd and 4th week (post-weeks 2, 3 and 4). No difference was observed in ITL (p>0.05). CMJ performance increased gradually from baseline to post-week 2 and from post-week 2 to post-week 4 (p<0.05). The average power in the first 15 seconds and average power of the four sets of 15 seconds of the IJT were higher in post-week 4 compared to baseline (p<0.01). Scores on the Fatigue and Injury scales of the RESTQ-Sport changed during training (p<0.05). We conclude that training applied during the pre-competitive period provided increments in CMJ performance and explosive strength endurance, and the changes in the RESTQ-Sport suggest that the athletes had adequate levels of stress and recovery.

O objetivo deste estudo foi analisar o efeito do treinamento físico aplicado em um período pré-competitivo na potência e na resistência de força explosiva de membros inferiores, no estresse e na recuperação de jovens atletas de voleibol. Sete atletas (15,8 ± 0,5 anos, 186,1 ± 6,6cm, 75,9 ± 1,8kg) de uma equipe de voleibol sub-16, do sexo masculino, foram treinados durante um período pré-competitivo de quatro semanas. A carga interna de treinamento (CIT) foi monitorada pelo método PSE da sessão. Testes de salto vertical com contramovimento (CMJ) e de natureza intermitente, de quatro séries de 15 segundos (TSVI), foram avaliados no 1º dia de treinamento (linha de base), no último dia da 2ª (pós-semana 2) e da 4ª semana (pós-semana 4). O Questionário RESTQ-Sport foi aplicado na linha de base, no último dia da 2ª, 3ª e 4ª semanas (Pós-semana 2, 3 e 4). A CIT não foi diferente (p>0,05). O CMJ aumentou no pós-semana 2, comparado com a linha de base e no pós-semana 4, comparado com o pós-semana 2 (p<0,05). A média de potência nos 15 segundos iniciais e a média de potência das quatro séries de 15 segundos do TSVI foram maiores no pós-semana 4, comparado à linha de base (p<0,01). As escalas Fadiga e Lesões do RESTQ-Sport se alteraram ao longo do treinamento (p<0,05). Conclui-se que o treinamento aplicado durante o período pré-competitivo proporcionou incrementos no CMJ e no TSVI, e as alterações no RESTQ-Sport sugerem que os atletas apresentaram níveis adequados de estresse e recuperação.

Efeito de quatro dias consecutivos de jogos sobre a potência muscular, estresse e recuperação percebida, em jogadores de futsal / Effect of four successive days of games in muscle power, perceived stress and recovery in futsal players

O objetivo desse estudo foi analisar o efeito de jogos de futsal realizados em dias consecutivos sobre o desempenho em testes de saltos verticais e sobre o estresse e a recuperação de atletas dessa modalidade. Participaram deste estudo 11 atletas do sexo masculino (24,3 ± 5,0 anos, 1,73 ± 0,07 cm, 75,7 ± 9,0 kg, 11,2 ± 4,1% de gordura), pertencentes a uma equipe de futsal. A equipe foi monitorada durante a fase final dos Jogos Abertos do Paraná, com jogos realizados em quatro dias consecutivos. O RESTQ-Sport foi aplicado antes e após a competição, e os testes de "squat jump" (SJ) e de salto vertical com contramovimento (CMJ) foram realizados na manhã de todos os dias de jogos. O SJ apresentou uma provável diminuição (0/34/66%) antes do segundo jogo comparado com antes do primeiro, uma muito provável diminuição (0/3/97%) antes do terceiro jogo comparado com antes do primeiro e uma provável diminuição (2/20/78%) antes do quarto jogo comparado com antes do primeiro. O CMJ apresentou uma provável diminuição antes do segundo (0/19/81%), terceiro (3/20/77%) e quarto jogo (1/10/89%) em relação à antes do primeiro. A escala recuperação física do RESTQ-Sport foi menor no pós-competição, comparada com o pré-competição (p < 0,05) e a escala fadiga foi maior no pós-competição comparada com pré-competição (p < 0,05). A diferença entre o Σ das escalas de recuperação e o Σ das escalas de estresse no pós-competição (7,5 ± 9,8) foi menor que o pré-competição (9,8 ± 9,1; p = 0,03). Em conclusão, o decréscimo no desempenho de saltos verticais e as alterações deletérias nas escalas do RESTQ-Sport sugerem que houve acúmulo de fadiga ao longo de jogos de futsal realizados em dias consecutivos.

The aim of this study was to analyze the effect of futsal games conducted on consecutive days on vertical jump performance test and stress and recovery of 11 professional players (male, 24.3 ± 5.0 years, 1.73 ± 0.07 cm, 75.7 ± 9.0 kg, 11.2 ± 4.1% fat). The team was monitored during the final phase of Paraná Open Games, with games in four consecutive days. The RESTQ-Sport questionnaire was applied before and after the competition, and the squat jump (SJ) and countermovement vertical jump (CMJ) tests were performed every morning when the games were held. The SJ presented a likely decrease when comparing before the second game to before the first game (0/34/66%) and before the fourth game to before the first game (2/20/78%), and a very likely decrease before the third game when compared to before the first game (0/3/97%). The CMJ showed a likely decrease before the second (0/19/81%), third (20/03/77%) and fourth game (01/10/89%) compared to before the first game. The physical recovery scale of the RESTQ-Sport was lower in the post-competition compared to pre-competition (p < 0.05) and the fatigue scale was greater in the post-competition compared to pre-competition (p < 0.05). The difference between the Σ recovery scales and the Σ stress scales in post-competition (7.5 ± 9.8) was lower when compared to the pre-competition (9.8 ± 9.1, p = 0.03). In summary, the decrease in vertical jump performance and deleterious changes in the RESTQ-Sport scales suggest a fatigue accumulation over consecutive days of futsal games.

Carbohydrate mouth rinse does not improve repeated sprint performance / Enxágue bucal com carboidrato não melhora o desempenho em sprints repetidos

The objective of this study was to evaluate the effect of a carbohydrate mouth rinse on the repeated sprint ability (RSA) of young soccer players. Nine youth soccer players (15.0 ± 1.5 years; 60.7 ± 4.84 kg; 1.72 ± 0.05 m; 20.5 ± 1.25 kg/m²) were selected. The athletes were submitted to an RSA test consisting of six sprints of 40 m (going/ return = 20 m + 20 m), separated by 20 s of passive recovery, under three experimental conditions: carbohydrate mouth rinse (CHO) or placebo (PLA) and control (CON). The mouth rinses containing CHO or PLA were administered 5 min and immediately before the beginning of the test in doses of 100 mL. The best sprint time (RSAbest), mean sprint time (RSAmean), and drop-off in sprint performance (fatigue index) were determined for the different treatments. One-way ANOVA for repeated measures did not identify significant differences (P > 0.05) in RSAbest (CHO = 7.30 ± 0.31 s; PLA = 7.30 ± 0.30 s; CON = 7.26 ± 0.16 s), RSAmean (CHO = 7.71 ± 0.30 s; PLA = 7.71 ± 0.25 s; CON = 7.66 ± 0.24 s), or fatigue index (CHO = 5.58 ± 2.16%; PLA = 5.77 ± 3.04%; CON = 5.55 ± 3.72%). The results suggest that a carbohydrate mouth rinse does not improve the repeated sprint performance of young soccer players.

O objetivo deste trabalho foi analisar os efeitos do enxágue bucal com carboidrato sobre o desempenho, durante sprints repetidos (RSA), de jovens jogadores de futebol. Nove atletas de futebol da categoria infantil (15,0 ± 1,5 anos; 60,7 ± 4,84 kg; 1,72 ± 0,05 m; 20,5 ± 1,25 kg/m²) foram submetidos ao teste de RSA. O teste foi composto por seis sprints de 40 m (ida/volta = 20 m + 20 m), separados por 20 s de recuperação passiva com três condições experimentais: enxágue bucal com carboidrato (CHO) ou placebo (PLA) e controle (CON). O enxágue bucal com CHO ou PLA foi conduzido 5 min antes e imediatamente antes do início dos testes em doses de 100 mL. O tempo do melhor sprint (RSAbest), a média de tempo dos sprints (RSAmean) e o índice de fadiga (IF) foram determinados nas diferentes condições experimentais. ANOVA one-way para medidas repetidas não identificou diferenças significantes (P > 0,05) para RSAbest (CHO = 7,30 ± 0,31 s; PLA = 7,30 ± 0,30 s; CON = 7,26 ± 0,16 s), RSAmean (CHO = 7,71 ± 0,30 s; PLA = 7,71 ± 0,25 s; CON = 7,66 ± 0,24 s) e IF (CHO = 5,58 ± 2,16%; PLA = 5,77 ± 3,04%; CON = 5,55 ± 3,72%). Os resultados sugerem que o enxágue bucal com CHO não parece capaz de melhorar o desempenho, sobre sprints repetidos, de jovens jogadores de futebol.

A estimulação transcraniana por corrente contínua como recurso ergogênico: uma nova perspectiva no meio esportivo / Transcranial direct current stimulation as an ergogenic aid: a new perspective in sport

Nas duas últimas décadas tem-se verificado um considerável aumento no interesse de um grande número de pesquisadores em investigar o potencial de diferentes recursos ergogênicos que possam contribuir na melhoria do desempenho físico de atletas de diferentes modalidades. Grande parte dos estudos tem focado os mecanismos subjacentes ao desenvolvimento da fadiga, pelo fato de que este fenômeno complexo é considerado um fator limitante do desempenho esportivo. Sendo assim, recursos ergogênicos que são eficientes em protelar o desenvolvimento da fadiga podem melhorar o desempenho esportivo. Apesar de haver muitas discussões sobre a fadiga, sua causa exata ainda é um assunto controverso. Apesar disso, tem sido sugerido que mecanismos corticais podem estar envolvidos e que estudos sobre a modulação de regiões cerebrais específicas podem trazer respostas valiosas para entender melhor este fenômeno. Atualmente, a estimulação transcraniana por corrente contínua (ETCC) vem sendo utilizada como uma ferramenta não invasiva capaz de modular a excitabilidade de regiões específicas do córtex cerebral. Dados preliminares têm demonstrado que a ETCC anódica é capaz de aumentar a excitabilidade do córtex motor por até uma hora após sua aplicação, e também aumentar o tempo até em exercício isométrico até à exaustão. Estes dados sugerem ser provável que a ETCC possa ser utilizada como uma ferramenta em pesquisas sobre mecanismos envolvidos no desenvolvimento da fadiga e, talvez, como um possível recurso ergogênico para atletas.

The last two decades has followed an increase in interest from a large number of researchers interested in investigating the ergogenic potential of different resources that might assist in improving the physical performance of athletes in different sports. Most studies have focused on the mechanisms underlying the development of fatigue as this complex phenomenon is a limiting factor in sports performance. Thus, ergogenic resources that are effective in delaying the development of fatigue may improve athletic performance. Despite many discussions about fatigue, its exact cause is still a controversial subject. However, it has been suggested that cortical mechanisms may be involved and studies that have tried to modulate specific brain regions can provide valuable answers to better understand this phenomenon. Currently, (tDCS) has been used as a noninvasive tool that can modulate the excitability of specific regions of the cerebral cortex. Preliminary data have shown that tDCS anode is able to increase the excitability of motor cortex for up to one hour after its application and also increase the time until exhaustion in isometric exercise. These data suggest that tDCS can probably be used as a tool in research on mechanisms involved in the development of fatigue and perhaps as a potential ergogenic aid for athletes..

A ingestão de cafeína não melhora o desempenho de atletas de judô / The intake of caffeine does not improve the performance of judo

O objetivo do presente estudo foi investigar os efeitos ergogênicos da ingestão de cafeína, sobre o desempenho motor de atletas de judô feminino. Participaram do estudo 13 atletas do sexo feminino (17,6 ± 1,6 anos, 58,3 ± 11,4 kg, 162 ± 4,1 cm, 22,5 ± 4 kg/m2), vinculadas à Federação Paranaense de Judô, por pelo menos dois anos. O desempenho motor foi avaliado mediante a utilização do Special Judô Fitness Test (SJFT), a partir do qual foi analisado o número de arremessos em cada bloco, número total de arremessos, frequência cardíaca (FC) final e de recuperação e o índice no SJFT. Os sujeitos foram testados em duas condições, após ingestão de cafeína (6 mg.kg-1) ou placebo (dextrose) 60 minutos antes dos testes, em um delineamento duplo-cego, cruzado. O número de arremessos em cada bloco não diferiu entre as condições cafeína (CAF) e placebo (PL) (Bloco A: 4,53 ± 0,51 CAF e 4,46 ± 0,51 PL; Bloco B: 8,3 ± 0,63 CAF e 8,23 ± 0,72 PL; Bloco C: 7,23 ± 0,59 CAF e 7,46 ± 0,77 PL), bem como o número total de arremessos (20,07 ± 1,18 CAF e 20,15 ± 1,67 PL), FC (Final: 190,3 ± 9,63 bpm CAF e 190,69 ± 9,19 bpm PL; Recuperação: 162,07 ± 13,78 bpm CAF e 164,3 ± 9,64 bpm PL) e índice no SJFT (17,59 ± 1,4 CAF e 17,75 ± 1,98 PL). A ingestão de cafeína não melhorou o desempenho durante atividade de alta intensidade e curta duração em lutadores de judô.

The objective of this study was to investigate the ergogenic effects of caffeine on motor performance of judo female athletes. Thirteen female athletes (17.6 ± 1.6 years, 58.3 ± 11.4 kg, 162 ± 4.1 cm, 22.5 ± 4 kg/m2), registered in the State Federation of Judo for at least two years, participated in this study. The motor performance was assessed using the Special Judo Fitness Test (SJFT), from which was considered the number of throws in each block, the total number of throws, recovery and final heart rate (HR) and final score in SJFT. The subjects were tested in two different conditions, after ingestion of gelatin capsules of caffeine (6 mg.kg-1) or placebo (dextrose) 60 minutes before testing in a randomized double-blind, crossover study. The number of throws in each block did not differs between the caffeine (CAF) and placebo (PL) conditions (Block A: 4.53 ± 0.51 CAF and 4.46 ± 0.51 PL; Block B: 8.3 ± 0.63 CAF and 8.23 ± 0.72 PL; Block C: 7.23 ± 0.59 CAF and 7.46 ± 0.77 PL), as well as the total number of throws (20.07 ± 1.18 CAF and 20.15 ± 1.67 PL), HR (Final: 190.3 ± 9.63 bpm CAF and 190.69 ± 9.19 bpm PL; Recovery 162.07 ± 13.78 bpm CAF and 164.3 ± 9.64 bpm PL) and final score in SJFT (17.59 ± 1.4 CAF and 17.75 ± 1.98 PL). Ingestion of caffeine did not improve performance during high intensity and short duration exercise in judo fighters.