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.

Cortical activity and gait parameter characteristics in people with multiple sclerosis during unobstructed gait and obstacle avoidance.

BACKGROUND: People with Multiple Sclerosis (PwMS) present higher cortical activity during walking. However, the cortical activity during gait while avoiding an obstacle is still not clear. OBJECTIVE: To investigate cortical activity and gait spatial-temporal parameters in PwMS during two different gait tasks (i.e., unobstructed and obstacle avoidance). METHOD: Fifteen PwMS and 15 healthy controls (CG) were recruited. Participants performed ten trials in each gait condition, wearing a 64-electrode cap electroencephalogram (EEG) at 1024 Hz. Kinematic data were obtained through 10 Vicon® cameras at 200 Hz. EEG was analyzed through four cortical areas (frontal, motor, parietal, and occipital cortex areas) and five frequency bands (delta, theta, alpha, beta, and gamma) obtained through the power spectral density. In addition, spatial-temporal gait parameters (e.g., step length and velocity) were measured. Two-way ANOVA (group x gait condition) and MANOVA (group x gait condition) were used to compare gait and EEG parameters, respectively. One-way ANOVA was used to compare groups in the crossing phase of the obstacle avoidance condition. RESULTS: PwMS presented lower step length and velocity, and higher cortical activity in frontal (beta and gamma) and parietal (gamma) cortical areas in both gait conditions compared to CG. Moreover, PwMS presented increased cortical activation (frontal and parietal) and decreased step length and velocity in obstacle avoidance compared with unobstructed gait. In addition, PwMS required more cortical resources (frontal and parietal) than CG to accomplish both gait conditions. During the obstacle avoidance task, it was further observed that PwMS positioned their feet closer to the obstacle, before and after the task, compared to CG. CONCLUSION: PwMS demand higher cortical resources to accomplish gait tasks, mainly when it is necessary to negotiate an obstacle in the pathway. This higher cortical activity may be a compensatory mechanism to deal with damage in subcortical structures caused by multiple sclerosis.

Influence of Side Uncertainty on Knee Kinematics of Female Handball Athletes During Sidestep Cutting Maneuvers.

Noncontact anterior cruciate ligament ruptures generally occur during unanticipated sidestep cutting maneuvers when athletes have their visual attention focused on the opponent. The authors investigated the influence of uncertainty related to the side to perform the sidestep cutting maneuver on knee kinematics of female handball athletes. A total of 31 female handball athletes performed the sidestep cutting maneuver during anticipated and uncertain conditions. During the uncertain condition, visual cues indicated the direction of the reactive sidestep cutting maneuver. Between-condition differences were compared using the Student t test for paired samples calculated with statistical parametric mapping. Lower knee flexion angle was detected during the uncertain condition compared with the anticipated condition for the nondominant limb (0%-8% of the sidestep cycle). Knee abduction was larger during the uncertain condition for both the dominant (15%-41% of the sidestep cycle) and nondominant (0%-18% of the sidestep cycle) limbs compared with the anticipated condition. The nondominant leg showed higher knee abduction (36%-68% of the sidestep cycle) during the uncertain condition compared with the anticipated condition. The athletes' approach velocity was slower during the uncertain condition. The uncertain condition impacted knee kinematics and potentially positioned the joint at greater risk of injury by decreasing the flexion angle in the nondominant leg and increasing the joint valgus bilaterally.

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. %HRmean (89.61 ± 2.31 vs. 88.03 ± 4.98 %HRmax) 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 %HRmax differed only in 60-70 %HRmax (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.

Virtual reality head-mounted goggles increase the body sway of young adults during standing posture.

The aim of this study was to investigate the effects of wearing virtual reality head-mounted goggles (VR) on body sway in young adults. We run two experiments, in which we compared the body sway while standing during the conditions of 1) wearing and non-wearing VR with eyes-opened (experiment #1), 2) wearing and no-wearing VR with eyes-closed (experiment #2), and 3) wearing VR with eyes-opened when the scene was turned on and off (experiment #2). Forty-four (experiment #1) and fifteen (experiment #2) young adults were instructed to remain as still as possible on a force plate for 60-s and performed three trials in each quiet standing condition. The center of pressure (CoP) displacement, mean velocity, root mean square (RMS), area and median frequency of sway were calculated in both experiments. In the experiment #1, wearing VR condition with eyes-opened largely increased the AP and ML CoP displacement, AP mean velocity, AP and ML RMS, and area (p < 0.05) compared to non-wearing VR with eyes-opened. In the experiment #2, no differences were found for any conditions (eyes-closed and eyes-opened with turned on and off VR scene). In conclusion, wearing VR head-mounted goggles increased body sway of young adults during standing postural task, when the individuals were with eyes-opened. However, the effects of wearing VR head-mounted goggles on body sway disappeared when the individuals were with eyes-closed or the google scene was turned off the scene compared to not wearing VR head-mounted goggles with eyes-closed or turned on scene, respectively.

ß-Alanine Supplementation's Improvement of High-Intensity Game Activities in Water Polo.

OBJECTIVES: To investigate whether 4 wk of ß-alanine supplementation improves total distance covered, distance covered and time spent in different speed zones, and sprint numbers during a simulated water polo game. DESIGN: Double-blind, parallel, and placebo controlled. A total of 11 male water polo players participated in the study, divided randomly into 2 homogeneous groups (placebo and ß-alanine). METHODS: The participants performed a simulated water polo game before and after the supplementation period (4 wk). They received 4.8 g·d-1 of dextrose or ß-alanine on the first 10 d and 6.4 g·d-1 on the final 18 d. RESULTS: Only the ß-alanine group presented a significant improvement in total sprint numbers compared with the presupplementation moment (PRE = 7.8 [5.2] arbitrary units [a.u.]; POST = 20.2 [7.8] a.u.; P = .002). Furthermore, ß-alanine supplementation presented a likely beneficial effect in improving total distance covered (83%) and total time spent (81%) in speed zone 4 (ie, speed ≥ 1.8 m·s-1). There was no significant interaction effect (group × time) for any variable. CONCLUSIONS: Four weeks of ß-alanine supplementation slightly improved sprint numbers and had a likely beneficial effect on improving distance covered and time spent in speed zone 4 in a simulated water polo game.

Kicking Performance and Muscular Strength Parameters with Dominant and Nondominant Lower Limbs in Brazilian Elite Professional Futsal Players.

The aims of the current study were to analyze a kick from 10 m in a futsal context and the parameters of muscular strength using an isokinetic dynamometer in a laboratory environment, performed with the dominant (DL) and nondominant lower limbs (NDL). Seventeen professional elite players participated. Kicking performance was evaluated from the second penalty mark. Next, athletes completed a strength evaluation with an isokinetic dynamometer at speeds of 60°â‹…s-1, 180°â‹…s-1, and 300°â‹…s-1. Significant differences were observed for hip (15.64 ± 3.44; 13.97 ± 2.62), ankle (63.19 ± 8.90; 52.55 ± 8.72), foot (82.31 ± 7.93; 68.41 ± 7.85), and ball (99.74 ± 8.45; 88.31 ± 7.93) speeds (km⋅h-1), and average power at 180°â‹…s-1 (325.59 ± 40.47; 315.79 ± 39.49 W), but not for accuracy (1.33 ± 0.57; 1.66 ± 0.77 m) between the DL and NDL, respectively. Few moderate correlations were observed in the DL (r = .54-.64) or NDL (r = .53-.55) between the kinematic variables of kick and muscular strength parameters (P < .05). We conclude that highly trained players present asymmetries in kicking motion; however, the imbalance in muscular strength is very small. We recommend that specific court tests be conducted to reliably characterize kicking performance in futsal. Success in kicking seems to be too variable and complex to be totally predicted only by joints, foot and ball speed, and lower limb muscular strength parameters.

Preliminary results on organization on the court, physical and technical performance of Brazilian professional futsal players: comparison between friendly pre-season and official match

The main aim of this study was to verify possible differences between a friendly pre-season match (FM) and an official in-season match (OM) regarding physical, technical, and organizational performances of a professional Brazilian futsal team. Ten professional futsal athletes participated in this study. The matches were monitored with video cameras (30 Hz) and athlete trajectories obtained with automatic tracking. The values obtained for distance covered per minute, percentage of distance covered at moderate intensity, team coverage area, spread, passes, possessions, ball touches and successful passes per minute were greater for the OM than FM. On the contrary, percentage of distance covered, standing and walking was greater for the FM than OM. We concluded that physical, technical, and tactical performances are different between a FM and an OM in futsal and also these parameters mutually influenced each other distinctly. Future studies should verify whether pre-season tournaments reproduce similar demands to a regular season official match

Efeito do treino neuromuscular na rotação do joelho durante a aterrissagem em mulheres / Neuromuscular training effect on knee rotation during drop landing in women / Efecto del entrenamiento neuromuscular en la rotación de la rodilla durante el aterrizaje en las mujeres

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.

Introduction: The high rate of injuries of the anterior cruciate ligament (ACL) without involving contact in women is a source of curiosity among scientists, because drop landing assessments may suggest a predisposition to the risk of this injury. In these sense, several training protocols have been used as an intervention and achieved mixed results in the change of this risk factor. Objective: The aim of this project was to evaluate the possible changes of rotation knee in single-leg drop landing after the intervention of a neuromuscular training program. Methods: The study included 18 women aged between 18 and 51 years, who were divided into two groups: neuromuscular training group (NTG) (n=11) and control group (CG) (n=7). In addition, they did not have musculoskeletal injury or pain in the lower limbs. Each participant completed five valid single-leg drop landings from a platform of 40 cm. The motion capture process was carried out with 12 infrared cameras of the OptiTrack(tm) system to obtain three-dimensional coordinates of markers fixed in the anatomical points of interest. The local coordinate systems of the thigh and leg were defined by means of the respective markers set in the anatomical points. Thus, the knee rotation angles in the sagittal, frontal, and transverse planes were calculated through the sequence of Euler angles and the angular velocities were calculated using the formulations of quaternions. Results: The results showed an increase in the knee rotation speed after the neuromuscular training. Conclusion: We conclude that neuromuscular training resulted in faster rotation at the knee in the 40 milliseconds succeeding the single-leg landing.

Introducción: El gran número de lesiones del ligamento cruzado anterior sin que implique un contacto en las mujeres es motivo de curiosidad entre los científicos porque las evaluaciones de aterrizaje pueden sugerir predisposición al riesgo de esta lesión. En este sentido, varios protocolos de entrenamiento se han utilizado como intervención y lograron resultados mixtos en el cambio de este factor de riesgo. Objetivo: El objetivo de este proyecto fue evaluar los posibles cambios de rotación de la rodilla en el aterrizaje unipodal después de la intervención de un programa de entrenamiento neuromuscular. Métodos: El estudio incluyó a 18 mujeres de edades comprendidas entre 18 y 51 años, que fueron divididas en dos grupos: grupo de entrenamiento neuromuscular de ocho semanas (GEN) (n = 11) y grupo control (GC) (n = 7). Además, no tenían lesión musculoesquelética o dolor en las extremidades inferiores. Cada participante realizó cinco aterrizajes unipodales válidos desde una plataforma de 40 cm. El proceso de captura de movimiento se llevó a cabo con 12 cámaras infrarrojas del sistema OptiTrack(tm) para obtener las coordenadas tridimensionales de los marcadores fijados a los puntos anatómicos de interés. Los sistemas de coordenadas locales del muslo y la pierna se definieron por medio de los respectivos marcadores establecidos en los puntos anatómicos. De esa manera, fueron calculados los ángulos de rotación de la rodilla en los planos sagital, frontal y transversal utilizando las secuencias de los ángulos de Euler, y las velocidades angulares utilizando las formulaciones de cuaterniones. Resultados: Los resultados mostraron un aumento en la velocidad de rotación de la rodilla después del entrenamiento neuromuscular. Conclusión: Se concluye que el entrenamiento neuromuscular resultó en mayor velocidad de rotación en la rodilla en los 40 milisegundos posteriores al aterrizaje unipodal.

Velocidade da bola no chute no futsal: comparação entre garotos com diferentes níveis de desempenho e correlação de variáveis preditoras do desempenho / Ball velocity on the kick in futsal: comparison between youth with different performance levels and correlation of the predictive variables of performance

O estudo objetivou comparar e verificar as possíveis correlações entre a velocidade da bola com a velocidade do pé, ângulo relativo do joelho e comprimento do último passo durante o chute entre garotos Praticantes e Não Praticantes do futsal. Participaram do estudo 14 garotos com idade entre 13 e 15 anos divididos em dois grupos, Praticantes (G1) e Não Praticantes (G2) de acordo com seu tempo de prática estruturada semanal na modalidade. Para a análise cinemática duas câmeras ajustadas a uma frequência de 120 Hz, foram fixadas lateralmente ao movimento realizado e focalizando os marcadores fixados no membro inferior do chute. Cada participante executou 10 chutes simulando uma cobrança de tiro livre no futsal. Os dados tridimensionais do membro inferior de chute foram obtidos pelo "software" DVIDEOW e tratados em ambiente Matlab, para obtenção das variáveis cinemáticas de interesse: velocidade da bola (VELBOLA), velocidade do pé (VELPÉ), ângulo de joelho (ANGJOELHO) e comprimento do último passo (CP). Todas as variáveis exibiram índices estatisticamente maiores em G1 se comparado a G2 e, além disso, não foram encontradas diferenças intertentativas na tarefa (p < 0,05). No G1 uma análise de regressão múltipla somente revelou influência na VELBOLA em 17% causada pelo CP. Além disso, no G2 nenhuma variável influenciou na VELBOLA. Pode-se concluir que as variáveis estudadas são diferentes entre praticantes e não praticantes de futsal com idade entre 13 - 15, e que a VELBOLA pode ser ligeiramente influenciada pelo CP nesta faixa etária. Recomenda-se que treinadores monitorem periodicamente o desenvolvimento desta característica do movimento, principalmente em jogadores novatos, como forma de identificar jogadores com diferentes níveis de desempenho no chute em um contexto de futsal.

The aim of this study was to compare and verify the possible correlations between ball velocity with foot velocity, knee angle and length of last stride between practitioners and non-practitioners of futsal game. Fourteen young males with aged between 13 and 15 years old divided into two groups: practitioners (G1) and non-practitioners (G2), according with the time of futsal structured practice. For the kinematic analysis we had used two cameras at a sampling frequency of 120 Hz, fixed laterally to the movement performed in order to focus the markers in the limb of kick. Each participant has performed ten kicks simulating a kick of ten meters in futsal. Three-dimensional data of the lower limb of kick were obtained in DVIDEOW software and treated in Matlab environment in order to obtain the variables of interest: ball velocity (VELBALL), foot velocity (VELFOOT), knee angle (ANGKNEE) and length of last stride (LLS). Statistically all data displayed higher levels in G1 compared to G2. In addition, no significant differences were found between trials in each group (p < 0.05). In G1 a multiple regression analysis revealed only influence on VELBALL 17% caused by LLS. Moreover, in G2 any variable have influenced VELBALL. However, we conclude that the variables are different between practitioners and non-practitioners of futsal game with aged between 13 and 15 years old, and the variable VELBALL could be little influenced by the LLS in this age band. Thus, we suggested that coaches maintain focus on development and monitoring this characteristic of movement, especially in novices, in order to identify players with different levels of performance of kicking in a futsal context.