Arremessar por cima do ombro e a distância percorrida pelo implemento / Overarm throw and the distance traveled by the implement

A habilidade de arremessar por cima do ombro tem sido bastante estudada, observando-se a velocidade do implemento, porém enquanto muitas tarefas têm como objetivo arremessar o mais longe possível, a distância percorrida pelo objeto ainda não tem sido investigada. O objetivo deste estudo foi verificar se existe relação entre o estágio de desenvolvimento motor nesta habilidade e a distância percorrida pelo implemento e observar diferenças entre os gêneros masculino e feminino; 50 crianças, com idade entre 7-8 anos, de ambos os gêneros, procedentes de Piracicaba - SP foram analisadas enquanto arremessavam uma bola de tênis de campo, o mais longe possível. Cada criança realizou três arremessos intercalados e foi filmada com duas câmeras mini DV, tanto em vista lateral quanto posterior, enquanto arremessava. O nível de desenvolvimento das crianças foi classificado, utilizando-se uma sequência de desenvolvimento e a distância percorrida pela bola foi registrada. Foi encontrada correlação significativa entre o nível do desenvolvimento e a distância atingida. Diferenças entre os gêneros foram observadas: os meninos encontravam-se em níveis desenvolvimentais mais avançados em todas as ações e alcançaram maiores distâncias. Assim, o nível de desenvolvimento desta habilidade mostrou-se importante para o alcance de seu objetivo (arremessar mais longe). Sugere-se que o nível de habilidade é influenciado pelo meio ambiente e que oportunidades de movimento devem ser providenciadas para auxiliar o desenvolvimento integral da criança.

Overarm throwing skill has been widely studied regarding the farthest throwing distance analysing the velocity of the implement; however the object's distance has not been investigated. The aim of this study was to verify if there is a relationship between the skill development and the distance reached by the object and to observe differences between genders. Fifty children, ages 7-8 years, both genders, from Piracicaba - SP, were analyzed while throwing a tennis ball as far as they could. Each child had three attempts. They were filmed with two mini DV cameras, from both side and rear views while performing. Children's movements were categorized using a developmental sequence and the distance covered by the ball was register. A positive correlation was found between the developmental level and the ball distance. Gender differences were observed; boys were in a more advanced levels in all actions and had farther throwing distances. So, developmental level of this skill was important to reach the task goal (throwing as far as possible). It is suggested that skill level is influenced by the environment and movement opportunities must be provided in order to help the children's global development.

Analysis of comparisons between the dominant hand and the non-dominant hand in overarm throwing motions and ball-throwing distance / 体力科学

The difference between the dominant hand and the non-dominant hand in overarm throwing motions and ball-throwing distances were studied in student women. The subjects were divided into a trained group and an untrained group. A switch thrower, categorized in the training group, was also examined. The throwing time, moving distance and mean velocity of the ball in the overall throwing phase, back-swing phase and acceleration phase were determined by a high-speed video analysis system. Seven empirical parameters estimated from the overall throwing motion were also introduced. These physical quantities and parameters were compared between the dominant and non-dominant hands. The ball-throwing distances in the trained and untrained groups were 2.58 and 1.73 times higher for the dominant hand than for the non-dominant hand, respectively. The difference in these values for both the hands of the switch thrower, however, were very small. The throwing time, moving time, and mean ball velocity in the back-swing phase in the trained group were 1.16, 1.65 and 1.35 times higher for the dominant hand than for the non-dominant hand, respectively. These phenomena were not observed in the untrained group and the switch thrower. The mean ball velocities in the acceleration phase for the trained and untrained groups were 2.0 and 1.5 times higher for the dominant hand than for the non-dominant hand, respectively. These values were more highly correlated with the ball-throwing distance in the trained group than in the untrained group. Significant correlations between seven parameters and ball-throwing distance were all observed for the dominant hand. However, only three of these parameters showed significant correlations for the non-dominant hand. These results show that the relationship between ball-throwing distance and throwing motion is closer for the dominant hand than for the non-dominant hand. In the present paper, possible roles of the dominant and non-dominant hands in the relationship between throwing motion and ball-throwing distance are also discussed.