THE RELATIONSHIPS BETWEEN ANTHROPOMOTORIC BODY DIMENSIONS AND THE FORCE - TIME STRUCTURE OF THE VERTICAL JUMP
Keywords: vertical jump, body dimensions, structure, relationships
AbstractINTRODUCTION: The take - off activities are quite various and many of their modifications are used in sport. The final result of the jump is influenced by a great variety of factors such as the quality of produced muscle strength timing of the jump, range of movement, arm activities etc. The basic determinants of many movement activities are the body dimensions (length and mass variables). This paper is focused on the questions concerning the relationship between the forcetime structure of the vertical jump (time, distance, velocity, force, final results) and the body dimensions. METHODS: The counter-movement vertical jump (CMJ) with an arm swing was registered on a KISTLER platform. The reaction force Fz (t) was analysed on an ON-LINE system using software developed in our lab. 23 variables describing the structure of CMJ from the point of view of time, distance, velocity of the centre of mass (CM), and produced force were computed in real time. Eleven values of body dimensions were measured for each subject (length variables of the lower limbs, body height, mass, width of knee, and ankle). The subjects of this research were two groups of students of physical education (men, n=54, age: 18 - 20 years, height: 178.40 ± 6.12cm, body mass: 79.00 ± 6.36 kg; women, n=47, height: 168.48 ± 6.20 cm, body mass: 59.77 ± 6.44 kg). Correlation and factor analysis (STATGRAPHICS package) were used for the statistical analysis. RESULTS: The factor analysis of eleven anthropometric values showed two groups of dependent variables (length parameters and body height - 1st factor, and body mass and width variables - 2nd factor). The three factor model of the CMJ structure selected three groups of dependent variables for both the men and women (1st - time and distance variables, 2nd - impulse momentum and variables of the final results of CMJ, 3rd - variables of the preparatory phase of the CMJ). The factor analysis of body dimension and CMJ variables has shown that the body dimensions are an independent group of variables and that they do not have a relationship to the CMJ structure. CONCLUSION: Factor analysis confirms the relative independence of the three groups of CMJ variables (time and distance, impulse momentum and final variables of the CMJ, the preparatory phase variables). The set of body dimension parameters does not have a relationship to the structure of CMJ. This finding was the same for both groups of men and women.
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