A cinematographical study of the relationship between speed of movement and available force

Abstract

The purpose of this study was to determine and compare the effects of horizontal velocity and jumping technique (one or two foot take-off) on the development and application of vertical force. More specifically, it was the purpose of this study to: (1) determine the relationship between horizontal velocity and vertical force for jumps off one foot and off two feet, (2) determine the relationship between horizontal velocity and vertical displacement for jumps off one foot and off two feet, and (3) determine an optimum horizontal velocity for attainment of maximum vertical force and vertical displacement. A total of 144 observations were recorded by use of a Locam high speed camera operating at 98 frames per second as the subjects (three volleyball and three basketball) performed the jumping trials for maximum vertical displacement using the selected horizontal velocities. Film analysis was expedited by utilization of a Vanguard Motion Analyzer. Kinematic and kinetic data, including horizontal and vertical velocities, vertical displacement, vertical acceleration and vertical force were collected for each subject's jumping performance. Descriptive research techniques which utilized tabular and graphic presentation of the results were utilized in this study. A general linear models procedure was employed to test the effects of horizontal velocity and horizontal velocity squared on vertical force. R-squares were determined in accounting for the variations in the dependent variable attributed to the independent variables. Analyses of variances were also employed in the data analysis. The relationship between horizontal velocity and vertical force was determined to be curvilinear for both jumping techniques. Significant relationships were found between horizontal velocity and horizontal velocity squared and vertical force for the volleyball subjects and between horizontal velocity and vertical force for the basketball subjects as analyzed in the GLM. The run and jump trials resulted in higher vertical values for each subject when compared to their vertical jump (zero horizontal velocity) trial. The higher values attained with an approach appears to result from the ability to transfer horizontal force and velocity into vertical force...