Auditory Information Reduces Response Time for Ball Rotation Perception, Increasing Counterattack Performance in Table Tennis

Purpose: Identifying the magnitude of ball rotation is critical to reduce response time, aiming to improve table tennis performance. This study analyzed the influence of auditory and visual information on the perception accuracy and counterattack performance of table tennis players. Methods: Twenty-two high-level table tennis players (22.5 ± 6.1 years, 71.2 ± 9.8 kg, 173.5 ± 7.7 cm) performed two tasks. In the first task, the athletes analyzed audio and video files of the forehand movement on a computer screen with auditory, visual, and combined information and, as soon as possible, chose the ball spin type on a keyboard: fast (spinning ball forward at 140 rotations per second (rotations/s); medium (105 rotations/s); slow (84 rotations/s); or flat hit (70 rotations/s). In the second task, the athletes performed 80 counterattacks (forehand movement) at the table on a target (68x38 cm) with and without auditory information. Results: Friedman's ANOVA revealed a significant effect of condition for perception accuracy (p < .001). Post hoc tests showed higher perception accuracy in the combined and visual conditions. ANOVA also revealed a significant effect of condition for response time to perceive ball rotation (p < .001). The response time was shorter in the combined condition than the other conditions for all spin types. Kendall's analyses showed no significant correlations between perception accuracy and response time in any ball spin type. Regarding the counterattack performance, the Wilcoxon signed-rank test indicated higher performance when auditory information was available (p = .022). Conclusions: As auditory information influences the response time and counterattack performance, it seems crucial for trainers and athletes to explore and include auditory perception training methods.

Is BDNF related to spatial-temporal gait parameters in people with multiple sclerosis? An observational study

BACKGROUND

It has been suggested that the protein Brain-derived Neurotrophic Factor (BDNF) plays a neuroprotective role in people with multiple sclerosis (pwMS). Also, BDNF seems to play a role in cognition performance. In the same line, gait in pwMS requires a higher cognitive resource, mainly during complex walking. Thus, maybe BDNF could be related to gait in pwMS.

OBJECTIVE

To investigate the relationship between BDNF and gait spatial-temporal parameters during unobstructed and obstructed conditions and the Timed Up and Go (TUG) in pwMS and healthy controls (HC).

METHODS

The study included 20 pwMS (11F/9M, 33.1±7.5 years, Expanded Disability Status Scale- EDSS 2.2±1.2) and 18 HC (13F/5M, 35.5±5.9 years). Both groups performed 20 gait attempts in two conditions: unobstructed walking (10 trials) and avoiding an obstacle. The obstacle was 15 cm in height and made of foam material. The BDNF serum concentration was collected with participants in fasting and completed before the clinical, gait, and mobility assessments. Clinical variables included the Symbol Digit Modality Test (SDMT), the Fatigue Severity Scale (FSS), and the International Physical Activity Questionnaire (IPAQ- short version). Associations between BDNF and spatial-temporal gait parameters, clinical variables, and TUG were determined by Pearson/Spearman correlations with Bonferroni's correction being applied (p<0.0013). Gait was compared by a two-way, repeated-measures ANOVA (group and condition) to characterize our cohort.

RESULTS

Reduced BDNF was observed for pwMS (41.66±4.45 ng/ml) in comparison with HC (61.67±7.07, p<0.001). However, although some correlations presented a moderate correlation between BDNF with gait variables, the correlations didn't reach a significant p-value after Bonferroni's correction. Lastly, pwMS presented shorter step length and slower step velocity for both gait conditions, with more evidence for obstacle conditions. Only pwMS changed gait behavior from unobstructed walking to obstacle avoidance conditions (i.e., reduced step length and velocity and increased step duration).

CONCLUSION

BDNF is not related to either clinical (i.e., EDSS, SDMT, FSS, or IPAQ) or gait parameters in pwMS and HC, even in a condition involving higher cognitive demand. These results may suggest that BDNF does not play a role in these parameters' performance.

Physiology Responses and Players' Stay on the Court During a Futsal Match: A Case Study With Professional Players

Physiological responses in futsal have not been studied together with temporal information about the players’ stay on the court. The aim of this study was to compare heart rate (HR) and blood lactate concentration ([La⁻]) responses between 1-H and 2-H considering the time of permanency of the players on the court at each substitution in a futsal match. HR was recorded during entire match and [La⁻] was analyzed after each substitution of seven players. %HR_mean (89.61 ± 2.31 vs. 88.03 ± 4.98 %HR_max) and [La⁻] mean (8.46 ± 3.01 vs. 8.17 ± 2.91 mmol·L⁻¹) did not differ between 1-H and 2-H (ES, trivial-small). Time in intensity zones of 50–100 %HR_max differed only in 60–70 %HR_max (ES, moderate). HR coefficient of variation throughout the match was low (7%) and among the four outfield players on the court (quartets, 5%). Substitutions (2 player’s participation in each half), time of permanence on the court (7.15 ± 2.39 vs. 9.49 ± 3.80 min), ratio between time in- and out-ratio on the court (In:Outcourt = 1:1.30 ± 1:0.48 vs. 1:1.05 ± 1:0.55 min) also were similar between 1-H and 2-H (ES, moderate and small, respectively). Balancing the number of substitutions, and the In:Outcourt ratio of players in both halves of the match, playing lower time at 1-H, ~8 min for each participation in the match, made it possible to maintain intensity of the match in 2-H similar to the 1H. These results are a good guidance to coaches and for application in future studies.

Game Running Performance and Fitness in Women’s Futsal

The study aimed to verify possible associations between game-play running performance and outcomes derived from fitness (running) tests in female futsal players. Sixteen women professional elite futsal players from a 1st division league team (19.2±2 years-old, 4.3±2.1 years of experience) participated. Firstly, a graded incremental treadmill test was adopted to determine maximal oxygen uptake (VO2max). Following 72 h of laboratory protocol, players were asked to perform a repeated-sprint test on a court (8×40 m with two 180° change-of-directions). Twenty-four hours after, players participated in a one-off friendly game (two 20-min half-times). A computerized automatic image recognition software (DVIDEOW; 30 Hz) allowed to determine game running performance variables. Fatigue index and best time in the court test and VO2max and its attached speed derived from laboratory-based test showed significant moderate-to-moderately high correlations (r=− 0.59–0.76; p<0.05) with some game running performance outputs, notably related to high-intensity running. In conclusion, the present study provided initial evidence on associations between two fitness tests and one-off game running performance in female futsal. Information derived from the work potentially help conditioning professionals working with female futsal athletes gain awareness about some properties of common testing tools.

Match Running Performance in Young Soccer Players: A Systematic Review

BACKGROUND

To date, athletic performance has been extensively assessed in youth soccer players through laboratory and field testing. Only recently has running performance via time-motion analysis been assessed during match play. Match running data are often useful in a practical context to aid game understanding and decision making regarding training content and prescriptions. A plethora of previous reviews have collated and appraised the literature on time-motion analysis in professional senior players, but none have solely examined youth players.

OBJECTIVE

The aim of the present systematic review was to provide a critical appraisal and summary of the original research articles that have evaluated match running performance in young male soccer players.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, literature searches were performed in four databases: PubMed, ISI Web of Science, SPORTDiscus and SciELO. We used the following descriptors: soccer, football, young, youth, junior, physical performance, running performance, match running performance, movement patterns, time-motion analysis, distances covered, activity profile, work rate, match analysis, and match performance. Articles were included only if they were original articles written in the English language, studied populations of male children and/or adolescents (aged ≤ 20 years), were published/ahead of print on or before 31 December 2017 and showed at least one outcome measure regarding match running performance, such as total distance covered, peak game speed or indicators of activities performed at established speed thresholds.

RESULTS

A total of 5801 records were found. After duplicates were removed and exclusion and inclusion criteria applied, 50 articles were included (n = 2615 participants). Their outcome measures were extracted and findings were synthesized. The majority of the reviewed papers covered the European continent (62%) and used global positioning systems (GPS) (64%). Measurement error of the tools used to obtain position data and running metrics was systematically overlooked among the studies. The main aims of studies were to examine differences across playing positions (20%), age groups (26%) and match halves (36%). Consistent findings pointed to the existence of positional role and age effects on match running output (using fixed running speed thresholds), but there was no clear consensus about reductions in activity over the course of match play. Congested schedules negatively affected players' running performance. While over 32% of all studies assessed the relationships between match running performance and physical capacity, biochemical markers and body composition, ~ 70% of these did not account for playing position.

CONCLUSIONS

This review collated scientific evidence that can aid soccer conditioning professionals in understanding external match loads across youth categories. Coaches working with youth development programs should consider that data derived from a given population may not be relevant for other populations, since game rules, match format and configuration are essentially unstandardized among studies for age-matched players. Despite limited evidence, periodization training emphasizing technical-tactical content can improve match running performance. Occurrence of acute and residual impairments in the running performance of young soccer players is common. Prescription of postmatch recovery strategies, such as cold water immersion and spa treatment, can potentially help reduce these declines, although additional research is warranted. This review also highlighted areas requiring further investigation, such as the possible influence of environmental and contextual constraints and a more integrative approach combining tactical and technical data.

Comparison of the Kinematic Patterns of Kick Between Brazilian and Japanese Young Soccer Players

Background

Kicking performance is the most studied technical action in soccer and lower limbs kinematics is closely related to success in kicking, mainly because they are essential in imparting high velocity to the ball. Previous studies demonstrated that soccer leagues in different countries exhibit different physical demands and technical requirements during the matches. However, evidencewhether nationality has any influence in the kinematics of soccer-related skills has not yet been reported. The nationality of the players is an aspect that might be also relevant to the performance in kicking.

Objectives

The aim of this study was to compare the lower limbs kinematic patterns during kicking, between Brazilian and Japanese young top soccer players.

Patients and Methods

Seven Brazilian (GA) and seven Japanese (GB) U-17 players performed 15 side-foot kicks each, with a distance of 20 m away from the goal, aiming a target of 1 × 1 m in upper corner, constrained by a defensive wall (1.8 × 2 m). Four digital video cameras (120 Hz) recorded the performance for further 3D reconstruction of thigh, shank and foot segments of both kicking and support limbs. The selected kicking cycle was characterized by the toe-off of the kicking limb to the end of the kicking foot when it came in contact with the ball. Stereographical projection of each segment was applied to obtain the representative curves of kicking as function of time for each participant in each trial. Cluster analysis was performed to identify the mean GA and GB curves for each segment. Silhouette coefficient (SC) was calculated, in order to determine the degree of separation between the two groups’ curves.

Results

Comparison between the median confidence intervals of the SC showed no differences between groups as regards lower limb patterns of movements. Task accuracy was determined by the relative frequency that the ball reached the target for all attempts and no differences were found (GA: 10.48 ± 14.33%; GB: 9.52 ± 6.51%; P = 0.88).

Conclusions

We conclude that lower limb kinematic patterns, in support and ball contact phases, are similar in young Brazilian and Japanese soccer players during free kicks when adopting the side-foot kick style.

EFEITO DO TREINO NEUROMUSCULAR NA ROTAÇÃO DO JOELHO DURANTE A ATERRISSAGEM EM MULHERES

Introdução: O grande índice de lesões do ligamento cruzado anterior sem envolver contato em mulheres é motivo de curiosidade entre os cientistas, pois avaliações de aterrissagem podem sugerir a predisposição ao risco dessa lesão. Neste sentido, vários protocolos de treinamento foram utilizados como intervenção e obtiveram resultados diversificados na alteração desse fator de risco. Objetivo: O objetivo deste projeto foi avaliar as possíveis alterações de rotação do joelho na aterrissagem unipodal após a intervenção de um programa de treinamento neuromuscular. Métodos: Participaram do estudo 18 mulheres com idade entre 18 e 51 anos, que foram distribuídas em dois grupos: grupo de treinamento neuromuscular de oito semanas (GTN) (n = 11) e grupo controle (GC) (n = 7). Além disso, não apresentavam lesão musculoesquelética ou dores nos membros inferiores. Cada participante realizou cinco aterrissagens unipodais válidas de uma plataforma de 40 cm de altura. O processo de captura de movimento foi realizado com 12 câmeras infravermelho do sistema OptiTrack(tm) para obter as coordenadas tridimensionais de marcadores fixados nos pontos anatômicos de interesse. Os sistemas de coordenadas locais da coxa e da perna foram definidos por meio dos respectivos marcadores fixados nos pontos anatômicos. Dessa forma, foram calculados os ângulos de rotação do joelho nos planos sagital, frontal e transverso através das sequências dos ângulos de Euler e as velocidades angulares através das formulações dos quatérnions. Resultados: Os resultados mostraram que houve um aumento na velocidade de rotação do joelho após o treinamento neuromuscular. Conclusão: Conclui-se que o treinamento neuromuscular resultou em maior velocidade de rotação no joelho nos 40 milissegundos que sucedem a aterrissagem unipodal.