Resumo
The purpose of this study was to investigate the variant and invariant motor control parameters (i ,e . , absolute and relative timing of joint reversal, absolute and relative force, and selected spatial features) in jumping from near its inception as a fundamental skill to its most sopihsticated, sport specific form. The Ínvestigation was directed by three questíons. First, which movement control parameters are variant and which are invariant across the standing long jump and the vertical jump early in life? Second, given that invariant control parameters for these two skills are found, then what changes, if any, occur with these control parameters in the course of motor development from childhood to adulthood? Finally, are the control parameters found in the standing long and vertical jump the same for sport specific jumps such as the volleyball spike and the dive roll? The subjects were 42 children and adults divided equally among seven groups. Four groups of children 3-,5-,7-, and 9-year-olds, and three groups of adults divided into one group of average adults, one group of skilled volleyball players, and one group of skilled gymnasts. Ali subjects were filmed from a sideview performing the standing long and vertical jumps. In addition, the volleyball players and the gymnasts were filmed while performing the volleyball spike and the dive roll, respectively. One trial per subject of each kind of jump was selected and digitized. The obtained coordinates were submitted to a computer program that calculated the parameters of interest. The data were examined according to the following design. The control parameters oí the standing long jump were compared with the control parameters of the vertical jump within the groups. The control parameters of the standing long and vertical jumps were compared with the control parameters of the volleyball spike, within the volleyball group. In the gymnasts group, the control parameters of the standing long and vertical jumps were compared with the control parameters of the dive roll. In general, the results showed invariance in absolute and relative timing and absolute and relative force between the two fundamental jumps in the children's and average adults groups. The variant par ameter was the spatial parameter. On the other hand, the comparisons of the control I parameters of the two fundamental jumps with the two sport specific jumps resulted in very few similarities. It was concluded that there seems to be one generalized motor program underlying the control of the two fundamental jumps (i,e., standing and vertical). However, there seems to occur significant changes in the program to control similar sport specific skills such as the volleyball spike and dive roll.
