THE EFFECTS OF PRACTICE ON THE KINETICS OF VERTICAL AND HORIZONTAL JUMPING
AbstractINTRODUCTION The purpose of this study is to determine the effects of practice onthe kinetics of vertical and horizontal jumping. A sub purpose of this study is to determine the relationship between peak power and distance jumped. The focus of this research is interdisciplinary in that an attempt will be made to understand vertical and horizontal jumping from both a Biomechanical and a Skill Acquisition perspective. The relationship between force and velocity is important in determining the peak power produced in vertical and horizontal jumping movements. Peak power is realized at the point in which the force time curve intercepts the velocity time curve (Dowling and Vamos, 1993). To understand the mechanics of jumping it is necessary to determine the relationship between force, velocity and peak power on the distance jumped. In terms of skill acquisition, practice isan important variable (Schmidt, 1988). As the learner performs a number of practice trials, they develop a memorial representation for the movement pattern. The kinetic components of the movement pattern may be importantdetenninants of skillful performance. Therefore, it is important to take into account the relationships between movement kinetics and movement outcome (i.e. distanceheight jumped), as a function of practice, to more fully understand the processes involved in the acquisition of a jumping skill. METHOD lkenty volunteer subjects were randomly assigned to either anexperimental or a control group. Subjects in the experimental group performed five maximal vertical and horizontal jumps daily for ten days. Pre and post tests were conducted on day one and day ten. Subjects performed three maximal vertical and horizontal jumps on an AMTI force plate. Power, force and velocity data was computed using the AMTI Power software. In addition, movement outcome (i.e., distance or height jumped) was measured. RESULTS AND DISCUSSION The prdpost mean differences in the temporal and kinetic variables were used to determine the effect of practice on the 'kinetics of jumping. In addition, multiple regression and correlation were used to determine the relationship between the temporal and kinetic variables and the distance jumped. The results are discussed in terms of the changes in time to peak power as a function of practice. In addition, the relationship between peak power and distance jumped is discussed in terms of the learning process. Implications for the role of practice in skill acquisition and efficiency as a determinant of skill acquisition are discussed. REFERENCES Dowling, J.J. & Vamos, L. (1993). Identification of kinetic and temporal factors related to vertical jump performance. Journal of Applied Biomechanics, 9,95-110. Schmidt, R.A. (1988). Motor Control and Learning: A Beehavioral Emphasis. (2nd ed.). Champaign, 11: Human Kinetics.
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