ABSTRACT
The main objective of this study was to analyze the motor variability in the performance of the tennis serve and its relationship to performance outcome. Seventeen male tennis players took part in the research, and they performed 20 serves. Linear and non-linear variability during the hand movement was measured by 3D Motion Tracking. Ball speed was recorded with a sports radar gun and the ball bounces were video recorded to calculate accuracy. The results showed a relationship between the amount of variability and its non-linear structure found in performance of movement and the outcome of the serve. The study also found that movement predictability correlates with performance. An increase in the amount of movement variability could affect the tennis serve performance in a negative way by reducing speed and accuracy of the ball.
ABSTRACT
O presente artigo tem o objetivo de oferecer uma tipologia de jogadores portadores de deficiência físicaque praticam a atividade desportiva do tênis em cadeira de rodas. Incluem-se a princípio, umas breves referênciasconcernentes ao deficiente físico, expressões cujo referente significativo inclui o jogador de tênis em cadeira derodas, que fica definido como aquele indivíduo que, como conseqüência de uma deficiência congênita ou adquirida,se vê impedido para realizar com normalidade as formas básicas do movimento. Os três quadros incorporados ao texto, que vêm a descrever os aspetos pontuais considerados na ôIntroduçãoõ, compõem, respectivamente,uma classificação das deficiências físicas que atendem as distintas seqüelas que estão presentes (neurológicas, miopáticas, ortopédicas e reumatológicas), um resumo dos tipos de lesões medulares (com indicação dosgrupos musculares envolvidos e os movimentos afetados), e os diferentes quadros que mostram as seqüelasocasionadas por uma lesão medular, os quais variam em função do número e a classe das extremidades afetadas(desde a monoplegia até a quadriplegia, passando pela paraplegia, a triplegia, a hemiplegia e a diplegia). Onúcleo temático deste trabalho vem constituído pela descrição das diversas categorias de jogadores de tênis emcadeira de rodas que devem se estabelecer em função de suas limitações, a saber: desportistas paraplégicos, tetraplégicos, jogadores com paralisia cerebral, atletas de espinha bífida, jogadores com poliomielite e jogadores com amputação de membros inferiores. Diferentes exemplos vêm ilustrar, complementando as referências teóricas dedicadas a estes tipos de tenistas em cadeira de rodas.
The present article has the objective to offer a typology of players who are beared of physical deficiencyand practice the tennis sport activity in wheel chair. At first, some brief references concerning the physical deficient are included, expressions which significant referring includes the tennis player in wheel chair, which is defined as the individual that, as a consequence of a congenital or acquired deficiency, is impeded of accomplishing, with normality, the basic forms of movement. The three situations incorporated to the text, which come to describe the punctual aspects considered in the ôIntroductionõ, compose, respectively, a classification of the physical deficiencieswhich attend the different sequels that are present (neurological, miopathic, orthopedical and rheumatic), a summaryof the types of marrow lesions (with indication of the involved muscular groups and the affected movements), and the different situations that show the sequels caused by a marrow lesion, which vary in function of number and theclass of the affected extremities (from the monoplegia to the quadriplegia, going through the paraplegia, triplegia,hemiplegia and diplegia). The thematic nucleus of this work is constituted by the description of the several categoriesof tennis players in wheel chair which should establish in function of their limitations, to be known: paraplegicsportsmen, tetraplegic, players with cerebral paralysis, athletes of bifid spine, players with poliomyelitis andplayers with amputation of the inferior members. Different examples come to illustrate, complementing the dedicatedtheoretical references to these types of tennis players in wheel chair.
