COMPARISON OF THE FORCE-TIME STRUCTURE OF THE VERTICAL JUMP BETWEEN MEN AND WOMEN

Abstract

INTRODUCTION The vertical jump is a relatively simple movement situation which is very ofkn used for the study of the performance in take-off activities, quality of the muscles, coordination of the movement etc. (e.g. Komi & Bosco, 1978; Bobbert, F. M.,1988; Sanders, R. H., 1992,1993 and others). The vertical jump can be used as a very suitable model for the solution of many problems in sport pedagogy, effectiveness of the training process and studying of the movement quality of man. The object of our research is not only the final performance, (i.e. final characteristic of the jump - height of jump), but we are interested in the course of the movement, timing, stability - reproducibility of the movement and other aspects. This study was a part of a larger research project. The main goal of this study is to focus on the following questions: What was the inter-individual variability of the structure of the vertical jump? How was the stability (reproducibility) of the movement during the vertical jump? What were the differences in the structure of the vertical jump between the men and women? The classical counter-movement vertical jump was at the center of our interest. Students of physical education - men (n = 54, body height = 178.40 ± 6.12 cm, body weight = 70.29± 6.36 kg, age = 18 - 20 years) and women (n = 47, body height = 8.48± 6.20 cm, body weight 9.72 ± 6.44 kg, age = 18-20 years) were the subjects of the research. They performed two counter-movement vertical jumps. The vertical component Fz was registered by using the KISTLER platform. The reaction force Fz(t) was analyzed on an on-line system by using our own software which derived the velocity-time and distance-time functions from the Fz(t) curve and computed 23 biornechanical variables describing the structure of the vertical jump from the point of view of time, force, impulse, velocity, and the track of the center of gravity. Data were elaborated by statistical procedures based on STATGRAPHICS package (basic statistical characteristics, t-test, correlation analysis). Statistical characteristics of measured variables have provided the information about the inter-individual variability of the time, force, track, and velocity structure of the movement in the vertical jump for both men and women. This information was the basis for the next step of our research. Reproducibility of the structure of the vertical jump varies for different groups of variables (rtt = 0.50 - 0.98). The highest stability was found in the strength parameters (take-off force, braking and accelerating impulse, rtt = 0.91-0.98) and the lowest level of stability for the time structure of the movement (at = 0.45-0.66). Statistical analysis has confmed a significant difference in the structure of the vertical jump between the group of men and women.