Comparação do padrão cinemático do chute no futebol entre jogadores de dois países
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Data
2005-07-29
Autores
Santiago, Paulo Roberto Pereira [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O objetivo desta pesquisa foi comparar os padrões cinemáticos dos membros inferiores, durante chutes com a parte medial do pé, realizados por 14 praticantes jogadores, de futebol sendo 7 de nacionalidade brasileira e 7 de japonesa. Cada participante realizou 15 chutes a gol, simulando uma cobrança de falta com barreira. Esses chutes foram filmados por 4 câmeras digitais, focalizando o membro de chute e de apoio dos participantes, nos quais foram colocados 5 marcadores passivos, nos pontos anatômicos de interesse, definindo, assim, os segmentos coxa, perna e pé. Os dados tridimensionais foram obtidos através de procedimentos de cinemetria. Em seguida, estes foram suavizados e realizou-se a projeção estereográfica dos vetores normalizados, obtendo-se, assim, curvas no plano que descrevem a movimentação dos segmentos, durante a execução do chute ao longo do tempo. Realizou-se o cálculo de uma curva média para as 15 curvas da projeção estereográfica de cada segmento (coxa, perna e pé) do membro de chute e apoio para cada um dos 14 participantes. Através das curvas médias de cada um, aplicou-se a análise por cluster, para cada segmento isoladamente, entre todas as curvas médias projetadas, a cada instante de tempo. Neste caso, foram definidos dois grupos e identificados em quais partes do ciclo do movimento houve uma separação em função do país do qual o participante era oriundo. Através dos resultados obtidos concluiu-se que o comportamento dos segmentos inferiores entre os grupos estudados (brasileiros e japoneses) apresentaram padrões cinemáticos semelhantes. Com relação ao acerto dos chutes, verificou-se que os comportamentos dos segmentos inferiores entre os chutes acertaram e os imprecisos apresentaram padrões cinemáticos semelhantes. Deste modo, não foram encontradas relações entre os chutes que acertaram o alvo e os chutes que não acertaram o alvo.
The purpose of this research has been to compare the kinematics patterns of the lower limbs during kicks with the medial part of the foot (pass kicks), performed by soccer practitioners of both Brazilian and Japanese nationalities. Each one performed 15 goal kicks, simulating a foul kick with a barrier. These kicks were registered in films, by 4 digital cameras, focusing the kick and the participantsþ support limbs, in which 5 passive markers were placed in the anatomical spots of interest, thus identifying the thigh, leg and foot segments. The 3D data were obtained through the kinemetry processes. Then, data were smoothed, and finally, a stereographic projection of normalized vectors was accomplished, producing curves in a plan, which described the placement frame by body segments during the kick. The average curve among each participant þs 15 curves was estimated. Through the average curves, a cluster analysis for each segment among all the projected average curves was applied separately, at every moment. In this case, two groups were defined and identified in order to be studied, and parts of the movement cycle in which there had been a separation were considered, due to the participant þs nationality. Through the results it was concluded that the behavior of the lower limbs between the groups -Brazilian X Japanese- presented a similar kinematic pattern. In relation to precision, two situations were presented. The first one, in which the kicks were precise, and the second one, in which they weren't. It was observed that the limb behavior in these two situations also presented similar kinematic patterns. Therefore, no relationship could be found between those kicks which hit the target, and the ones which didn't.
The purpose of this research has been to compare the kinematics patterns of the lower limbs during kicks with the medial part of the foot (pass kicks), performed by soccer practitioners of both Brazilian and Japanese nationalities. Each one performed 15 goal kicks, simulating a foul kick with a barrier. These kicks were registered in films, by 4 digital cameras, focusing the kick and the participantsþ support limbs, in which 5 passive markers were placed in the anatomical spots of interest, thus identifying the thigh, leg and foot segments. The 3D data were obtained through the kinemetry processes. Then, data were smoothed, and finally, a stereographic projection of normalized vectors was accomplished, producing curves in a plan, which described the placement frame by body segments during the kick. The average curve among each participant þs 15 curves was estimated. Through the average curves, a cluster analysis for each segment among all the projected average curves was applied separately, at every moment. In this case, two groups were defined and identified in order to be studied, and parts of the movement cycle in which there had been a separation were considered, due to the participant þs nationality. Through the results it was concluded that the behavior of the lower limbs between the groups -Brazilian X Japanese- presented a similar kinematic pattern. In relation to precision, two situations were presented. The first one, in which the kicks were precise, and the second one, in which they weren't. It was observed that the limb behavior in these two situations also presented similar kinematic patterns. Therefore, no relationship could be found between those kicks which hit the target, and the ones which didn't.
Descrição
Palavras-chave
Futebol, Biomecânica, Chute, Padrão cinemático, Projeção estereográfica, Análise por Cluster, Soccer, Biomechanics, Kick, Kinematics pattern, Projection espheriographical, Analysis by Cluster
Como citar
SANTIAGO, Paulo Roberto Pereira. Comparação do padrão cinemático do chute no futebol entre jogadores de dois países. 2005. vi, 79 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências, 2005.