DETERMINANTS OF THE THROWING VELOCITY IN HANDBALL -A STATISTICAL MODEL
AbstractINTRODUCTION The aim of the research was to find the influence of the basic anthropometrical and motor ability parameters on the ball velocity during throws in handball. These relationships seem to be very important for coaches, in order to improve the selection quality and the efficiency of training methods. The last task is particularly difficult among experienced players. METHODS Twelve high-performance handball field players took part in the experiment. The following somatic anthropometric indices were used: length, skeleton width, musculature and adiposity (28 parameters for each player). The average linear ball velocity was measured using a special photocell system. Muscle strength was evaluated on a special stand (locally made) under static conditions (flexors and extensors of elbow, shoulder, knee and hip joints and trunk). The speed-strength characteristics of the upper extremity were measured on the modified CES Ariel. Subjects performed simulated throws in the sitting position. The maximal and average mechanical power of the lower extremity and trunk was measured during the vertical CMJ performed on a force platform. The mean value (SD) was calculated for each parameter. A normality of distributions was examined using the Shapiro-Wilk test. At the next stage Pearson's correlation matrix and a multiple regression analysis were used (pe0.05). The raw data was recalculated to values in the T-scale and according to the Doolittle method the contribution to throwing velocity was calculated. The best regression subset was assigned using Fisher's discriminating method. The regression hyperplane parameters were estimated. RESULTS Expected values of the ball velocity (R=0.982; R~=o9.6 3): Y = 0.018 XI + 0.733 X2 + 0.039 Xg -0.332 Xq + 0.006 Xg - 2.854 where: X1 - max. angular velocity of the bar (36%), X2 - range of fingers (41%), X3 - average mechanical power in CMJ (3%), Xq - shoulder width (6%), Xg - isometric muscle strength of trunk flexors (1 1 %). After recalculation to T-values the final equation contains two main factors: anthropometric (A) and motor (M): y=0.017 A + 0.072 M + 10.571 (R=O 857) The proportional contribution of these factors in expected value of the ball velocity is 11.9% and 61.4%, respectively. The hyperplane parameters, which divides subjects into two groups according to throwing velocity criterion, are as follows: 0.149 M + 0,051 A - 23.821 = 0 CONCLUSIONS These results suggest that the most important throwing velocity determinant is the motor abilities level. Among analyzed parameters the strength of trunk flexors (abdominal muscles) and maximal arm (shoulder joint) angular velocity have a decisive effect on the ball velocity in handball. REFERENCES Atwater A.B. (1980) Exer. Spod Sci. Rev. 7:43-85. Bartlett L.R., Storey M.D., Sirnons B.D. (1 989) Am. J. Sports Med. 1 7: 89-91 . Eliasz J., Janiak J., Wit A. (1990): Sporf Wyczynowy 911 0: 17-23. Joris ti., Muijen Van A.E., lngen Schenau Van G.J., Kemper H.C.G. (1 985) J. Biom. 18:409-414. Muijen Van A.E., Jiiris H., Kemper H.C.G., lngen Schenau Van G.J. (1991). Sports Training, Med. Rehab. 2: 103-1 13.
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