Upper limb movement characteristics in volleyball athletes / Características do movimento dos membros superiores em atletas de voleibol / Características del movimiento de las extremidades superiores en atletas de voleibol

ABSTRACT Introduction Passing and serving are the most direct and efficient tactics for scoring points in volleyball. The recoil of the upper limbs in dominating the ball requires strength and muscular explosion, where the effect of the body's angular momentum accompanies a joint and rhythmic action. Objective This study aims to analyze muscle strength in upper limb movements in volleyball athletes. Methods Several volleyball players volunteered for the research. The movement when the athlete hits the ball was analyzed using kinematic analysis. The relationship between muscle strength and ball movement was also analyzed. Results Body muscle tissue can be effectively trained during volleyball practice. The compound movements also help in the elasticity of the abdominal muscles. The stimulation of other muscle groups was observed in the participation of the movements. Conclusion In modern volleyball training, athletes should strengthen their training with rapid trunk muscle swing exercises to improve the coordination ability of the sets of muscle groups. The protocols presented can assist in improving players' skills and performance. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMO Introdução Passar e servir são as táticas mais diretas e eficientes de marcar pontos no voleibol. O recuo dos membros superiores no domínio da bola requer força e explosão muscular onde o efeito do momento angular do corpo acompanha uma ação conjunta e rítmica. Objetivo O objetivo deste estudo é analisar a força muscular no movimento dos membros superiores em atletas de voleibol. Métodos Vários jogadores de voleibol voluntariaram-se para a pesquisa. Foi analisado o movimento quando o atleta acerta a bola utilizando o recurso de análise cinemática. Também foi analisada a relação entre a força muscular e o movimento da bola. Resultados O tecido muscular corporal pode ser efetivamente treinado durante a prática do voleibol. Os movimentos compostos também auxiliam na elasticidade da musculatura abdominal. O estímulo de outros grupos musculares foi observado na participação dos movimentos. Conclusão No treinamento moderno de voleibol, os atletas devem fortalecer o treinamento com exercício rápido de balanço dos músculos do tronco para melhorar a capacidade de coordenação dos conjuntos de grupos musculares. Os protocolos apresentados podem auxiliar na melhoria das habilidades e no desempenho dos jogadores. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

RESUMEN Introducción El pase y el saque son las tácticas más directas y eficaces para conseguir puntos en el voleibol. El retroceso de los miembros superiores en el dominio del balón requiere fuerza y explosión muscular donde el efecto del momento angular del cuerpo acompaña una acción conjunta y rítmica. Objetivo El objetivo de este estudio es analizar la fuerza muscular en el movimiento de las extremidades superiores en atletas de voleibol. Métodos Varios jugadores de voleibol se ofrecieron como voluntarios para la investigación. El movimiento cuando el atleta golpea la pelota se analizó mediante la función de análisis cinemático. También se analizó la relación entre la fuerza muscular y el movimiento del balón. Resultados El tejido muscular del cuerpo puede entrenarse eficazmente durante la práctica del voleibol. Los movimientos compuestos también ayudan a la elasticidad de los músculos abdominales. Se observó la estimulación de otros grupos musculares en la participación de los movimientos. Conclusión En el entrenamiento moderno de voleibol, los atletas deben reforzar su entrenamiento con ejercicios de balanceo rápido de los músculos del tronco para mejorar la capacidad de coordinación de los conjuntos de grupos musculares. Los protocolos presentados pueden ayudar a mejorar las habilidades y el rendimiento de los jugadores. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

Kinematic analysis of lower extremity movement techniques in soccer training / Análise cinemática das técnicas de movimento dos membros inferiores no treinamento de futebol / Análisis cinemático de las técnicas de movimiento de los miembros inferiores en el entrenamiento de fútbol

ABSTRACT Introduction The improvement of soccer sports skills depends on many training efforts and is closely related to intrinsic scientific methods. Attention to the integral quality of the lower limb muscles and the performance of specific exercises of technical movements is essential to reach the optimal state of physical performance in players. Objective Analyze the kinematic effect of lower limb movement techniques in soccer training. Methods 10 athletes were marked with reflective spheres and submitted to the kinematic training method of the lower limbs designed by the coaches in 60 minutes, three times a week, for six weeks. Before and after the experiment, data captured by reflective spheres were captured, compared, classified, and analyzed. Results Kinematic training can effectively optimize movement time, swing amplitude, swing angle, and other aspects of lower limb mechanical structure, thus improving energy expenditure and making the movement concise, conveying strength and precision. Conclusion Trainers should seriously study the principles of applied kinematic analysis and optimize the training program from a scientific point of view because the athletic level of athletes is significantly improved with this real-time feedback. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMO Introdução O aprimoramento das habilidades esportivas do futebol depende de muitos esforços de treinamento e está intimamente relacionado com métodos científicos intrínsecos. Atenção na qualidade integral dos músculos dos membros inferiores e a realização de exercícios específicos de movimentos técnicos é essencial para atingir o estado ótimo da performance física nos jogadores. Objetivo Analisar o efeito cinemático das técnicas de movimento dos membros inferiores no treinamento de futebol. Métodos 10 atletas foram marcados com esferas reflexivas e submetidos ao método de treinamento cinemático dos membros inferiores desenhado pelos treinadores num período de 60 minutos, três vezes por semana, durante 6 semanas. Antes e depois do experimento, os dados capturados por esferas reflexivas foram capturados, comparados, classificados e analisados. Resultados O treinamento cinemático pode otimizar efetivamente o tempo de movimento, amplitude de balanço, ângulo de balanço e outros aspectos da estrutura mecânica dos membros inferiores, melhorando assim o dispêndio energético e tornando o movimento conciso, transmitindo força e precisão. Conclusão Os treinadores devem estudar seriamente os princípios da análise cinemática aplicada, otimizar o programa de treinamento do ponto de vista científico, pois o nível esportivo dos atletas é melhorado significativamente com a adição desse feedback em tempo real. Nível de evidência II; Estudos terapêuticos - investigação dos desfechos do tratamento.

RESUMEN Introducción La mejora de las capacidades deportivas en el fútbol depende de muchos esfuerzos de entrenamiento y está estrechamente relacionada con métodos científicos intrínsecos. La atención sobre la calidad integral de los músculos de los miembros inferiores y la realización de ejercicios específicos de movimientos técnicos es esencial para alcanzar el estado óptimo del rendimiento físico en los jugadores. Objetivo Analizar el efecto cinemático de las técnicas de movimiento del miembro inferior en el entrenamiento de fútbol. Métodos 10 atletas fueron marcados con esferas reflectantes y sometidos al método de entrenamiento cinemático de los miembros inferiores diseñado por los entrenadores en un período de 60 minutos, tres veces por semana, durante 6 semanas. Antes y después del experimento, se capturaron, compararon, clasificaron y analizaron los datos captados por las esferas reflectantes. Resultados El entrenamiento cinemático puede optimizar eficazmente el tiempo de movimiento, la amplitud del balanceo, el ángulo de balanceo y otros aspectos de la estructura mecánica de las extremidades inferiores, mejorando así el gasto de energía y haciendo que el movimiento sea conciso, transmitiendo fuerza y precisión. Conclusión Los entrenadores deberían estudiar seriamente los principios del análisis cinemático aplicado, optimizar el programa de entrenamiento desde un punto de vista científico, ya que el nivel atlético de los deportistas mejora significativamente con la incorporación de esta información en tiempo real. Nivel de evidencia II; Estudios terapêuticos - investigación de los resultados del tratamiento.

Reciprocating Kinematics of X-Smart Plus, VDW Silver and, iRoot Endodontic Motors: A Comparison Between Real and Set Values

Abstract This study assessed 3 endodontic motors, X-Smart Plus (Dentsply Sirona, Ballaigues, Switzerland), VDW.Silver Reciproc (VDW GmbH, München, Germany) and, iRoot (Bassi Endodontics, Belo Horizonte, Brazil) in 2 different reciprocating settings. The movements evaluated were 170° in counter-clockwise (CCW) and 50° in clockwise (CW) at 350 RPM, and 150° CCW and 30° CW at 300 RPM. For the X-Smart Plus and VDW Silver the settings used were the ones in the motor library. For the iRoot, the motor was adjusted to the angles of the study. A customized optic target was attached to the contra-angle of the motor and the movements were recorded with a high-resolution camera (K2 DistaMaxTM Long-Distance Microscope System, Infinity Photo-Optical Company, Colorado, EUA) at 2,400 frames per second (FPS). The images were analyzed with the Vision Research software (Inc. Headquarters, Wayne, New Jersey, EUA). The following kinematic parameters were assessed: CCW angle, CW angle, speed (RPM) at both directions, and, standstill time at each change of directions. The Intraclass Correlation Coefficient (ICC) and Kruskal-Wallis (method of Dunn) were used at a significant level of 5%. There was no statistically significant difference among the motors at the 150°/30° setting (P > .05); the iRoot was the least reliable at the 170°/50° setting for CCW angle, speed, and net angle parameters (P < 0.05). The standstill time of all motors in both directions was identical. None of the motors were able to reproduce faithfully the set movements. The iRoot motor presented a higher discrepancy when compared to X-Smart and VDW Silver.

Resumo Este estudo avaliou 3 motores endodônticos, X-Smart Plus (Dentsply Sirona, Ballaigues, Suíça), VDW.Silver Reciproc (VDW GmbH, Munique, Alemanha) e iRoot (Bassi Endodontics, Belo Horizonte, Brasil) em 2 diferentes ajustes de movimento reciprocante. Os movimentos analisados foram: 170° em sentido anti-horário (CCW) e 50° em sentido horário (CW) a 350 RPM, e 150° CCW e 30° CW a 300 RPM. Para os motores X-Smart Plus e VDW Silver os ajustes usados foram os que se apresentam nos ajustes pré-definidos dos motores. Para o iRoot o motor foi ajustado para os ângulos do estudo. Um alvo ótico customizado foi preso ao contra ângulo do motor e os movimentos foram gravados com uma câmara de alto resolução (K2 DistaMaxTM Long-Distance Microscope System, Infinity Photo-Optical Company, Colorado, EUA) a 2.400 quadros por segundo (FPS). As imagens foram analisadas com o sotware Vision Research (Inc. Headquarters, Wayne, Nova Jersey, USA). Os seguintes parâmetros de cinemática foram avaliados: ângulo anti-horário, ângulo horário, ângulo líquido, velocidade (RPM) em ambas direções e tempo de parada a cada mudança de direção. O Coeficiente de Correlação Intraclasse (ICC) e o teste de Kruskal-Wallis (método de Dunn) foram usados com nível de significâncias de 5%. Não houve diferença estatisticamente significante entre os motores no ajuste de 150°/30° (P > .05); o motor iRoot foi o menos confiável no ajuste de 170°/50° para o ângulo anti-horário, velocidade e ângulo líquido (P < 0.05). O tempo de parada em todos os motores foi idêntico em ambas as direções. Nenhum dos motores foi capaz de reproduzir fielmente os movimentos. O motor iRoot apresentou maior discrepância quando comparado com o X-Smart Plus e VDW Silver.

200-m front crawl performance over a training season in 12 years and underage-group swimmers: growth and kinematics effects

Abstract Aims: analyze kinematics, anthropometrics, and maturation during a training season in 12 y and underage-group swimmers, quantifying changes and estimating their contributions to the 200-m maximal front crawl time trial test (T200) (time trial/fixed distance), as an event representative of the swimming performance. Methods: Nineteen age-group swimmers (11 girls and 8 boys; age 10.0 ± 1.3 y and 10.6 ± 1.0 y) performed a T200 four times during the training season. Changes in kinematic and anthropometric variables throughout the season were calculated. We applied generalized estimating equations to compare the variables over the four experimental tests. Multiple linear regressions were applied to identify the most influential variables and the relative contribution of anthropometrics and kinematics to swimming performance of T200 at baseline (pre-season) and after (using delta values) each macrocycle. Results: Large improvements (d = 1.76) were observed in the T200's performance (from 85.5 ± 38.2 at pre-season to 175.2 ± 50.1 FINA points at the end season). A gender effect was not identified. Stroke rate, stroke length, and stroke index explained, respectively 59, 23, and 17% of the T200 performance changes along the season (R2 = 0.81; F = 26.9; p < 0.001; Durbin-Watson: 1.5). Anthropometric was not related to performance changes, with kinematic being the most determinant factor. Conclusion: Kinematical approaches must be carefully considered by coaches when planning 12 y and underage-group swimmers training programs.

Markerless Gait Analysis System Based on Deep Learning Fusion algorithm / 医用生物力学

Objective Taking three-dimensional (3D) motion capture system (MoCap) as the gold standard, a deep learning fusion model based on bi-lateral long short-term memory (BiLSTM) recurrent neural network and linear regression algorithm was developed to reduce system error of the Kinect sensor in lower limb kinematics measurement. Methods Ten healthy male college students were recruited for gait analysis. The 3D coordinates of the reflective markers and the lower limb joint centers were simultaneously collected using the MoCap system and the Kinect V2 sensor, respectively. The joint angles of lower limbs were calculated using the Cleveland clinic kinematic model and the Kinect kinematic model, respectively. The dataset was constructed using the MoCap system as the target and the angles via the Kinect system as the input. A BiLSTM network and a linear regression model for all lower limb angles were developed to obtain the refined angles. A leave-one subject-out cross-validation method was employed to study the performance of the models. The coefficient of multiple correlations (CMC) and root mean square error (RMSE) were used to investigate the similarity and the mean deviation between the joint angle waveforms via the MoCap and the Kinect system. ResultsIn comparison with the linear regression algorithm, the BiLSTM had better performance in the aspect of dealing highly nonlinear regression problems, especially for hip flexion/extension, hip adduction/abduction, and ankle dorsi/plantar flexion angles. The deep learning refined model significantly reduced the system error of Kinect. The mean RMSEs for all joint angles were mainly smaller than 10°, and the RMSEs of the hip joint were smaller than 5°. The joint angle waveforms presented very good similarity with the golden standard. The CMCs of joint angles were greater than 0.7 except for hip rotation angle. Conclusions The markerless gait analysis system based on deep learning fusion model developed in this study can accurately assess lower limb kinematics, joint mobility, walking functions, and has good prospect to be applied in clinical and home rehabilitation.

Kinematics Study of Glenohumeral Joint at Different Arm Elevation Planes in Normal Chinese / 医用生物力学

Objective To investigate relative translations of the glenohumeral joint during abduction, scaption and forward flexion in normal Chinese, so as to provide references for diagnosis, treatment and follow-up of glenohumeral joint instability and subacromial impingement syndrome.Methods The biplanar fluoroscopy system combined with model-image registration technique were used to measure the humeral translation relative to the scapular in 13 healthy volunteers during abduction, scaption and forward flexion.Results The anterior-inferior glenohumeral translation during abduction, scaption and forward flexion was (4.0±1.3), (4.1±1.5),(4.8±1.9) mm, respectively. The superior-inferior glenohumeral translation was (3.0±1.0), (3.1±1.1), (3.3±1.5) mm, respectively. During the whole motion, there was a significant difference in superior-inferior translation at different arm elevation angles, while other significant differences were not found.Conclusions For normal Chinese, the humeral head was positioned posteriorly and superiorly on the glenoid. During forward flexion, the anterior-inferior and superior-inferior glenohumeral translation was the maxium. Therefore, in the process of clinical diagnosis, treatment and follow-up, patients performing the forward flexion may obtain a better evaluation effect.

Gait Analysis of Hip Disarticulation Amputees Based on Kinematic Parameters and Plantar Pressure Measurement / 医用生物力学

Objective To analyze the gait characteristics of hip disarticulation amputees, and analyze the reasons for their differences from normal gait, so as to assist clinical diagnosis and evaluation. Methods Through the portable human motion capture device and plantar pressure analysis system, the kinematics and plantar pressure information of 5 hip amputees were collected and compared with 15 healthy volunteers in control group. Gait differences between the amputees and normal subjects and between the affected leg side and the healthy leg side of the amputees were compared. Results The proportion of double-support period for hip amuptees was higher than that of normal gait. Step length, step time, loading response period, mid support period, pre-swing period, proportion of the swing period for the affected leg side and healthy leg side of hip amputees showed significant differences with those of control group. The relative symmetry index of the gait for hip amputees was 0.60±0.05. Compared with the affected leg side, the support period of the healthy leg side was extended, the step length was shortened, the ground reaction force was greater than that of the affected leg side, and the center of pressure trajectory shifted to the affected leg side. Conclusions The gait of hip amputees is significantly different from that of normal people. Hip amputees have weak walking ability, poor gait symmetry, and they lack of continuity in the body’s center of gravity. The results provide experimental basis and theoretical analysis for the design of mechanical structure and control system of novel hip prosthesis.

O tempo de balanço como variável preditiva da doença de Parkinson / El tiempo de equilibrio como variable predictora de la enfermedad de Parkinson / Swing time as a predictive variable for Parkinson's disease

RESUMO Atualmente, a doença de Parkinson (DP) tem seu diagnóstico baseado apenas na observação clínica de uma combinação de sintomas, o que pode levar ao diagnóstico tardio. Alguns indivíduos podem, em decorrência disso, ter a doença por 5 a 10 anos antes de serem diagnosticados. O objetivo deste estudo foi identificar as variáveis cinemáticas temporais da marcha, pois estas são capazes de discriminar idosos com e sem DP. Como método, 40 indivíduos foram divididos em dois grupos: grupo de idosos sem DP (n=21) e com DP (n=19). Foram obtidos dez ciclos de marcha consecutivos durante a marcha em velocidade de preferência, sendo utilizados para a análise dos dados. Realizou-se uma análise discriminativa para determinar um modelo preditor de alterações na marcha característico da DP. O modelo foi calculado com base na especificidade e sensibilidade de cada variável analisada, utilizando-se variáveis cinemáticas temporais. A variável com valor discriminativo de sensibilidade e especificidade foi o tempo de balanço, o que pode classificá-lo como a variável que possui grande potencial preditivo da presença ou não da DP, e o ponto de corte encontrado para essa variável foi de 0,48 segundos. A pesquisa concluiu que a análise cinemática da marcha permite discriminar um grupo de indivíduos com a doença de Parkinson de um grupo de indivíduos saudáveis, com alta sensibilidade e especificidade, por meio do tempo de balanço, visto que ele é menor no grupo acometido pela doença.

RESUMEN Actualmente, el diagnóstico de la enfermedad de Parkinson (EP) se obtiene desde la observación clínica de una combinación de síntomas, lo que puede llevar a un diagnóstico tardío. Como resultado, algunas personas pueden haber adquirido la enfermedad entre 5 y 10 años antes de que fuesen diagnosticadas. El objetivo de este estudio fue identificar las variables cinemáticas temporales de la marcha, ya que son capaces de diferenciar a los ancianos con EP y a los ancianos sin EP. Se dividieron los 40 participantes en dos grupos: ancianos sin EP (n=21) y ancianos con EP (n=19). Se obtuvieron diez ciclos de marcha consecutivos durante la marcha a la velocidad preferida para el análisis de datos. Se realizó un análisis discriminante para determinar un modelo predictivo de cambios en la marcha característicos de la EP. El modelo se calculó con base en la especificidad y sensibilidad de cada variable analizada, utilizando variables cinemáticas temporales. La variable con valor discriminante de sensibilidad y especificidad fue el tiempo de equilibrio, que puede clasificarse como la variable con mayor potencial para predecir la presencia o no de EP; y el punto de cohorte encontrado para esta variable fue de 0,48 segundos. Se concluye que el análisis cinemático de la marcha puede discriminar a un grupo de individuos con enfermedad de Parkinson de un grupo de individuos sanos, con alta sensibilidad y especificidad, por medio del tiempo de equilibrio, que fue menor en el grupo afectado por la enfermedad.

ABSTRACT Currently, Parkinson's Disease (PD) is diagnosed based only on the clinical observation of a combination of symptoms, which can lead to late diagnosis, since some individuals may have the disease for 5 to 10 years before being diagnosed. The aim was to identify temporal kinematic variables of walking, capable of discriminating elderly people with and without PD. 40 individuals were divided into two groups: elderly group without PD (n=21) and with PD (n=19). Ten consecutive gait cycles were obtained during walking at a preferred speed and used for data analysis. A discriminative analysis was performed to determine a predictor model of gait changes, characteristic of PD and calculated based on the specificity and sensitivity of each variable analyzed, using temporal kinematic variables. The variable with discriminative value of sensitivity and specificity was the time of balance, which can be classified as the variable with most predictive potential of the presence or not of PD, and the cut of found for this variable was 0,48 seconds. The kinematic gait analysis allows to discriminate a group of individuals with PD from a group of healthy individuals with high sensitivity and specificity, through the time of balance that is lower in the group affected by the disease (cut of 0,48 seconds).

Effect of kinesio tape on scapular kinematics in subjects with scapular dyskinesis

Scapular dyskinesis is an abnormality in scapula static or dynamic position. There are several techniques for scapular dyskinesis conservative treatment, including Kinesio Tape application, which is used to promote and support scapula joint alignment, decrease pain and improve local muscle control. The study aim to investigate the effect of kinesio tape on scapular kinematics in subjects with scapular dyskinesis. Fourteen subjects with scapular dyskinesis performed flexion and scaption movements in two conditions: (1) without load and (2) holding a dumbbell. A scapular tape was applied over the lower trapezius (Y shaped) muscle with a 20% tension. Kinematic data were captured with 10 infrared cameras and analyzed based on Euler angles, peak values of upward rotation, internal rotation, and posterior tilt angles. To compare the situations with and without kinesio tape the repeated measures two-way ANOVAs (α = 0.05) was performed using SPSS software. Scapular tape increase upward rotation and posterior tilt during flexion of the shoulder. No interaction (Load x KT) was found during flexion, suggesting that KT effect in the peak values is the same, regardless the load condition. Scapular tape decreases internal rotation during scaption and a significant interaction was found between load x KT, suggesting the effect of using KT could depend the load u sed during this movement. The results suggest that kinesio tape may can be use as assistant to increase upward rotation, posterior tilt and decrease internal rotation in scapular dyskinesis subjects. (AU)

O tempo de balanço como variável preditiva da doença de Parkinson / Tiempo de equilibrio como variable predictora de la enfermedad de Parkinson / Swing time as a predictive variable for Parkinson's disease

RESUMO Atualmente, a doença de Parkinson (DP) tem seu diagnóstico baseado apenas na observação clínica de uma combinação de sintomas, o que pode levar ao diagnóstico tardio, uma vez que alguns indivíduos podem ter a doença por 5 a 10 anos antes de serem diagnosticados. O objetivo do estudo foi identificar variáveis cinemáticas temporais da marcha capazes de discriminar idosos com e sem DP. 40 indivíduos foram divididos em dois grupos: grupo de idosos sem DP (n=21) e com DP (n=19). Dez ciclos de marcha consecutivos foram obtidos durante a marcha em velocidade de preferência, e utilizados para a análise dos dados. Realizou-se uma análise discriminativa para determinar um modelo preditor de alterações na marcha característico da DP e calculado com base na especificidade e sensibilidade de cada variável analisada, utilizando-se variáveis cinemáticas temporais. A variável com valor discriminativo de sensibilidade e especificidade foi o tempo de balanço, o que pode classificá-la como a variável com grande potencial preditivo da presença ou não da DP; o ponto de corte encontrado para essa variável foi de 0,48segundos. A análise cinemática da marcha permite discriminar um grupo de indivíduos com DP de um grupo de indivíduos saudáveis com alta sensibilidade e especificidade, por meio do tempo de balanço, menor no grupo acometido pela doença (corte de 0,48 segundos).

RESUMEN Actualmente, el diagnóstico de la enfermedad de Parkinson (EP) se obtiene desde la observación clínica de una combinación de síntomas, lo que puede llevar a un diagnóstico tardío, ya que algunas personas pueden haber adquirido la enfermedad entre 5 y 10 años antes de la realización del diagnóstico. El objetivo del estudio fue identificar variables cinemáticas temporales de la marcha capaces de diferenciar a ancianos con EP y ancianos sin EP. Se dividieron los 40 participantes en dos grupos: ancianos sin EP (n=21) y ancianos con EP (n=19). Para el análisis de datos, se obtuvieron diez ciclos de marcha consecutivos durante la marcha a la velocidad preferida. Se realizó un análisis discriminante para determinar un modelo predictivo de cambios en la marcha característicos de EP que se calcula en base a la especificidad y sensibilidad de cada variable analizada utilizando variables cinemáticas temporales. La variable con valor discriminante de sensibilidad y especificidad fue el tiempo de equilibrio, que se puede clasificar como la variable con mayor potencial para predecir la presencia o no de EP; el punto de cohorte encontrado para esta variable fue de 0,48 segundos. El análisis cinemático de la marcha tiene una alta sensibilidad y especificidad en la identificación de individuos con EP comparados a individuos sanos por medio del tiempo de equilibrio, que es menor en el grupo afectado por la enfermedad (cohorte de 0,48 segundos).

ABSTRACT Currently, Parkinson's Disease (PD) is diagnosed based only on the clinical observation of a symptom combination, which can lead to late diagnosis, since some individuals have the disease for 5 to 10 years before diagnosis. The aim of this study was to identify temporal kinematic variables of gait, capable of discriminating older adults with or without PD. Forty individuals were divided into two groups: older adults without PD (n=21) and with PD (n=19). Ten consecutive gait cycles were obtained during gait at a preferred speed and then used in data analysis. Discriminative analysis was performed to determine a predictor model of gait changes, characteristic of PD, estimated based on the specificity and sensitivity of each analyzed variable, with temporal kinematic variables. The variable with discriminative value of sensitivity and specificity was swing time, which can be classified as the variable with most predictive potential of PD, and the cut-off point found for this variable was 0.48 seconds. Kinematic gait analysis allows discriminating a group of individuals with PD from a group of healthy individuals, with high sensitivity and specificity, through the swing time, which is lower in the group affected by the disease (cut-off=0.48 seconds).

Block slope is the main determinant of block phase performance in swimming / A inclinação do bloco é o principal determinante do desempenho da fase de bloco em natação / La inclinación del bloque es el principal determinante del desempeño de la fase de bloque en natación

ABSTRACT Introduction Swimming starts are an important component for decreasing the total race time, especially in short events. In this phase of swimming, the aim is to increase performance using many different techniques and starting platforms. Objectives The effects of height and slope of the starting block on kick-start performance were assessed in this study. Methods Six male competitive swimmers performed 24 kick-starts using four block settings: 65 cm & 75 cm flat and 65 cm & 75 cm sloped. Two-dimensional kinetic and three-dimensional kinematic data were analyzed, including average and maximum horizontal/vertical forces and impulses; reaction times; movement and block times; and take-off vertical/horizontal velocities. Two-way within-subject design ANOVAs were implemented to test the effects of block height and slope on the kinetic and kinematic variables. Results Block slope was the main factor affecting most of the dependent variables. Shorter block and movement times, greater average and maximum vertical forces, vertical impulse, and maximum horizontal force were found for the sloped settings. An inverse relationship was found between block height and 0-5 m times. Conclusion Based on the results, blocks with height of 75 cm and slope of 10° provided better results in swimmers' performance in the block phase. Level of evidence II, Therapeutic Studies -Investigating the Results of Treatment

RESUMO Introdução As largadas de natação são um componente importante para reduzir o tempo total de competição, especialmente em eventos curtos. Nessa fase da natação, o objetivo é aumentar o desempenho usando várias técnicas e plataformas de largada distintas. Objetivos Neste estudo, foram avaliados os efeitos da altura e da inclinação da plataforma sobre desempenho da saída kick-start. Métodos Seis nadadores de competição do sexo masculino realizaram 24 largadas, usando quatro tipos de bloco de partida (65 cm e 75 cm de altura planos e 65 cm e 75 cm com inclinação). Foram analisados dados cinéticos bidimensionais e cinemáticos tridimensionais, incluindo forças e impulsos horizontais/verticais médios e máximos; tempos de reação, movimento e de bloco; e velocidades vertical/horizontal da decolagem. Empregou-se o método ANOVA bidirecional intraindivíduo para analisar os efeitos da altura e da inclinação do bloco sobre as variáveis cinéticas e cinemáticas. Resultados A inclinação do bloco foi o principal fator que afetou a maioria das variáveis dependentes. Nas plataformas de largada inclinadas, verificou-se que os tempos de bloco e movimento eram mais curtos e as forças verticais médias e máximas, o impulso vertical e a força horizontal máxima foram maiores nas configurações inclinadas. Foi encontrada uma relação inversa entre a altura do bloco e os tempos para as distâncias de 0 a 5 metros. Conclusões Com base nos resultados, os blocos com 75 cm de altura e 10 graus de inclinação forneceram melhores resultados de desempenho dos nadadores na fase de bloco. Nível de Evidência II - Investigação dos resultados do tratamento.

RESUMEN Introducción Las largadas de natación son un componente importante para reducir el tiempo total de competición, especialmente en eventos cortos. En esta fase de natación, el objetivo es aumentar el desempeño usando varias técnicas y plataformas de largada distintas. Objetivos En este estudio, fueron evaluados los efectos de la altura y de la inclinación de la plataforma sobre desempeño de la salida kick-start. Métodos Seis nadadores de competición del sexo masculino realizaron 24 largadas, usando cuatro tipos de bloque de partida (65 cm y 75 cm de altura planos y 65 cm y 75 cm con inclinación). Fueron analizados datos cinéticos bidimensionales y cinemáticos tridimensionales, incluyendo fuerzas e impulsos horizontales/verticales promedios y máximos; tiempo de reacción, movimiento y de bloque; y velocidades vertical/horizontal del despegue. Se empleó el método ANOVA bidireccional intraindividuo para analizar los efectos de la altura y de la inclinación del bloque sobre las variables cinéticas y cinemáticas. Resultados La inclinación del bloque fue el principal factor que afectó a la mayoría de las variables dependientes. En las plataformas de largada inclinadas, se verificó que los tiempos de bloque y movimiento eran más cortos y las fuerzas verticales promedio y máximas, el impulso vertical y la fuerza horizontal máxima fueron mayores en las configuraciones inclinadas. Fue encontrada una relación inversa entre la altura del bloque y los tiempos para las distancias de 0 a 5 metros. Conclusiones Con base en los resultados, los bloques con 75 cm de altura y 10 grados de inclinación proporcionaron mejores resultados de desempeño de los nadadores en la fase de bloque. Nivel de Evidencia II; Investigación de los resultados del tratamiento

End posture analysis and motion planning based on UR3 manipulator puncture navigation / 国际生物医学工程杂志

Objective:To establish a motion planning method for avoiding singularities for manipulator-assisted puncture surgery navigation, and design the corresponding computer program.Methods:According to the actual operation and the need of clinicians, the puncture needle sleeve installed at the end of the UR3 robotic arm was designed, and the kinematics analysis and simulation verification of the robotic arm were performed. A calculation program for solving the movement pose when the puncture needle at the end of the robotic arm reaches the target position, and a motion planning program for avoiding singularities through small-angle rotation were programmed.Results:Six groups of joint angles were randomly selected, and the theoretical coordinates calculated by the program were compared with the actual coordinates. The result showed that the error between the theoretical value and the actual value was small, which proved the correctness of the kinematics model. In the verification experiment, 3 sets of initial poses at random were simulated, the best pose was obtained by the program. Then the pose was transmitted into the control system to control the movement of the robotic arm. The verification experiment results showed that the puncture needle can reach the target point, and the singularity can be effectively avoid by the small-angle rotation of the fixed central axis.Conclusions:The singular point avoidance method based on end posture rotation can effectively avoid the failure of initial target posture motion planning, and it has reference value for the application of manipulator in puncture surgery.

Variable Quasi-circular Gait Planning with Smooth Angular Acceleration for Lower Limb Rehabilitation / 中国康复理论与实践

Objective:To solve the problem of leg shaking caused by the sudden change of angular acceleration at the joint of periodic motion during circular gait training of lower limb rehabilitation robot. Methods:A kind of quasi-circular gait was proposed, which divided the periodic motion into three phases: start phase, middle phase and end phase. The time was equal in the start phase and the end phase, and could be adjusted with the parameter ratio. The joint trajectories of the two phases were planned by quintic polynomial, and the middle phase was still the circular gait joint trajectory. The trajectory of the proposed quasi-circular gait was simulated. Results:The angular velocity was continuously differentiable and 0, the angular acceleration was continuous and 0, and the end-effector trajectory became flat with the increase of ratio. The results on the physical prototype of the lower limb rehabilitation robot were principally consistent with the simulation, and the machine worked smoothly. Conclusion:The proposed variable quasi-circular gait had smooth angular acceleration at the junction of periodic motions, which effectively solved the jitter problem when using circular gait for lower limb rehabilitation training and avoided secondary injury to the patients.

Advance in Scapular Dyskinesis and Its Rehabilitation Management (review) / 中国康复理论与实践

Conclusion:The clinical assessment and classification of scapular dyskinesis had been summarized. Scapular dyskinesis is mainly secondary to rotator cuff injury, subacromial impingement syndrome, glenohumeral instability, injury of acromioclavicular joint, throwing shoulder and adhesive capsulitis, etc. Scapular exercise may be a supplement to routine rehabilitation management. Objective:To review the pathogeny, clinical assessment and classification, and rehabilitation management of scapular dyskinesis. Results and Methods:The literatures in recent ten years were reviewed and summarized.

Biomechanical Characteristics and Sports Risk Analysis on Foot-Ankle Joints of Badminton Players at the Moment of Landing / 医用生物力学

Objective To explore the influence of biomechanical characteristics of badminton players on sports risk at the moment of foot and ankle landing, so as to provide references basis for avoiding the sports risk of high-frequency and high-intensity landing of ankle joint of beginners. Methods Using three-dimensional force measuring platform and motion capture system, the kinematic and dynamic data of 30 badminton beginners (experimental group) and 30 high-level athletes (control group) at the kick-off (1 step) moment during ankle landing were collected. Results The angles of metatarsal flexion and dorsiflexion in experimental group were significantly smaller than those in control group, and the angles of varus and internal rotation in experimental group were significantly larger than those in control group. The left-right forces in experimental group were significantly larger than those in control group, and there was no significant difference in anterior-posterior force and vertical force between experimental group and control group. The valgus and external rotation torque of experimental group were significantly higher than those of control group, and the internal rotation torque of control group was significantly higher than that of experimental group. Conclusions Compared with beginners, the ankle movement of professional athletes has good dynamic stability and flexibility, the cushioning task can be completed with a smaller range of movement and force in left-right direction, and the angle of metatarsal flexion and dorsiflexion of professional athletes is relatively increased. It is also the embodiment of good training effect, so that the buffer time is slightly longer to prevent the impact of sudden landing of the ankle.

Analysis and Diagnosis on Backhand Twist Technique of Leading Men’s Player of National Table Tennis Team / 医用生物力学

Objective To make analysis and diagnosis on backhand twist technique used by player A, who is the leading men’s player of national table tennis team, so as to provide references for improving his backhand twist technique. Methods The three-dimensional kinematics test and analysis were used. The backhand twist techniques of player A and those of player B who has good backhand twist techniques were compared by quantitative data and picture analysis. Results At the stage of swinging racket backward, the racket swing amplitude, shoulder angle and wrist angle of player A were significantly smaller than those of player B. The roll angle of trunk of player A was significantly larger than that of player B. At the stage of swinging and hitting the ball, the shoulder angle, elbow angle of player A were significantly bigger than those of player B, while the increasing amplitude of shoulder angle and elbow angle, as well as the changing amplitude in roll angle of trunk of Lin Guoyuan were significantly smaller than those of player B. At the stage of swinging racket forward, the shoulder angle and elbow angle of player A were significantly bigger than those of player B. The increasing amplitude of shoulder angle and elbow angle, as well as the roll angle of trunk and its changing amplitude of player A were significantly smaller than those of player B. Conclusions The racket swing amplitude of player A was smaller, and the distance between the racket and the ball of player A was close at the end of swinging racket backward stage. During swinging and hitting the ball stage, the hitting point was far from the body, the shoulder joint was not stable enough to support, so that the wrist was used more. The center of gravity was not enough to force forward, and the outburst power was not concentrated. At swinging racket forward stage, player A’s braking was not active enough, which affected the stability of hitting the ball. At hitting the ball stage, the torsion of the trunk was smaller, and the waist power was not concentrated. On the basis of unaffecting the forehand outburst power, player A should slightly adjust his backhand twisting technique, or appropriately increase the the racket swing amplitude and torsion of the body. In the process of hitting the ball, the sequence of outburst power was the waist, the forearm and the wrist.

Comparison of Rotational Techniques between Chinese and World Elite Men’s Shot Put Athletes / 医用生物力学

Objective To compare rotational techniques used by Chinese and world elite men’s shot put athletes, so as to provide scientific references for Chinese male shot putters to improve their sports performance and results in international competitions. Methods Three-dimensional (3D) kinematics data from Chinese male shot putters in actual competitions were obtained, and kinematic parameters of Chinese and world elite men’s shot put athletes were calculated and compared. Namely, shot velocities and hip-shoulder separation angles at five critical instants of rotational techniques: right foot off, left foot off, right foot touchdown, left foot touchdown and release, as well as phase durations and shot travel distances during four critical phases: first single support, air-born flight, second single support and final delivery. ResultsCompared with world elite athletes, Chinese male shot putters using rotational techniques had significantly lower vertical release velocity, longer air-borne duration, smaller hip-shoulder separation angles at left foot off and touchdown instant, and longer shot travel distance during air-borne flight, but shorter shot travel distance during final shot delivery. Conclusions The difference in lower extremity strength is a primary casue leading to different sports performance between Chinese and world elite male shot putters. The technique differences in Chinese and world elite male shot putters mainly lie in different phase timing and shot travel distances during different techinique phases.

Effects of Gender and Maneuvers on ACL Injury Risk Factors for Volleyball Players / 医用生物力学

Objective To study the effect of gender and maneuvers on anterior cruciate ligament (ACL) injury risk factors for volleyball players. Methods Sports biomechanics data of volleyball players during stop-jump, drop landing and sidestep cutting were collected. The ACL injury rate and biomechanical parameters of simulated injured jumps were obtained with Monte Carlo simulation. The influence of gender and maneuvers on ACL injury risk factors was validated by 2×3 mixed designed two-way ANOVA. Results Sidestep cutting was the highest risk maneuver of ACL injury for both genders (P＜0.001). Compared with male players, female players had a greater risk of ACL injury during sidestep cutting and stop-jump (P＜0.001), while male players were more prone to have ACL injury than female players during drop landing (P＜0.001). The risk factors of ACL injury obtained by simulation were significantly influenced by gender and maneuvers (P＜0.001). Conclusions Male players were more likely to increase ACL load due to smaller knee flexion, forward leg tilt and heel landing than female players during sidestep cutting, while female players owned larger ground reaction force (GRF) and knee extension moment. Smaller knee flexion angle during stop jump was the major risk factor for both genders, however more characteristics contributed to the males. Female players with large GRF, knee valgus and extension moment, and heel-landing were likely to have ACL injury, while the small knee flexion angle was the key risk factor for male players. The results can provide evidences for evaluation of volleyball players’ ACL injury risk, individualized injury prevention protocols, and clinical treatment and rehabilitation directions.

Bowling: Occupational Hazards of the Wrist and Hand in Elite Tenpin Bowlers

@#Introduction: Bowling is an immensely popular, but scarcely researched sport associated with overuse injuries in its participants. The purpose of this study was to investigate and report on the incidence of common upper extremity complaints in elite bowling athletes. Materials and methods: All Malaysian national level bowlers (n=39) were evaluated via questionnaire on their upper limb symptoms. A focused, relevant clinical examination was performed on each subject to exclude de Quervain’s tenosynovitis, tennis and golfer's elbow, carpal tunnel syndrome and trigger finger. The athletes were then allowed to resume bowling for two hours before completing another symptom-related questionnaire. Results: Pain was the predominantly observed symptom, with a predilection for the wrist, ring and middle fingers, and thumb. De Quervain’s tenosynovitis was found in 53.8% (n=21) of the subjects, with 52.4% and 42.9% of them experiencing pain during and after training, respectively. Other repetitive injury-related disorders were also considerably more common than in their non-playing limb and the general population. Conclusion: The incidence of de Quervain’s tenosynovitis was exceptionally high in this population. Further studies on sports kinematics are needed to prevent long term morbidities in these athletes.

Characteristics of Different Tai Chi Step Types Based on AnyBody Simulation / 医用生物力学

太极拳； AnyBody仿真； 下肢； 动力学； 运动学