EFFECT OF FORCE CHARACWRISTICS AND REACTION ABILITY ON VERTICAL JUMPING IN YOUNG BASKETBALL PLAYERS
AbstractINTRODUCTION AND PURPOSE A vast quantity of scientific literature exists on the mechanisms and determinants of jumping ability. Yet, the influence of a) the maximum isometric push-off force, b) the speed by which maximum push-off force is developed, and c) the reaction ability to drop jump on the effective use of horizontal and drop vertical velocities in vertical jumping has not been thoroughly investigated. It was, thus, the purpose of this study to investigate the relationship and influence of these parameters on vertical jumping in young basketball players. Nine young male basketball players (age: 13.34 yrs; height: 1.71m; weight: 60.2 Kg) were tested on: a) maximum isometric push-off force (F-); b) vertical countermovement jumps with (CMJw) and without (CMJw,) the use of the arms; c) vertical jump from a flexed hip, knee, and ankle joint position (SJ); d) drop vertical jumps from heights of 18 (DJ18), 36 (DJ,,), and 42 cm (DJ,,); e) vertical jumps with one step (CMJ,), and horizontal velocities of 1.5 (CMJ,), and 2.2 mlsec (CMJ,); and, f) vertical jumps with self-paced horizontal velocity with (CMJ,) and without (CMJ,,) the use of the arms. Two pairs of photo cells, and two 1-D dynamometers were used for data collection. RESULTS AND CONCLUSION T-test results showed no significant differences (p <. 05) between: a) CMJw (M = 36.35cm) and CMJ, (M = 37.89cm), b) CMJwo(M = 30.45cm) and CMJ, (M = 30.45cm), CMJ, (M = 30.02cm), CMJ, (M = 31.68cm), and CMJ, (M = 31.99cm), and c) SJ (M = 27.49cm) and DJ,,. (M = 25.44cm) DJ36, (M = 26.82cm), and DJ, (M = 26.08cm). Evaluation of Fmax (M = 1.8 times body weight), per cent of Fmax achieved during the first lOOms (PCFM,,) (56% of F-), and reaction ability (ratio between best DJ and SJ jumps) (-2.5%) showed that this group of young basketball players was inferior to previously reported performance values for Fmx (2.8 times body weight), PCFM,, (70-75% of Fmax) (Papadopoulos, 1997). and reaction ability (20-25%, Schmiedt bleicher, 1994). It was concluded that, in vertical jumping, effective utilization of horizontal and drop vertical velocities is influenced by Fmx, PCFM,,, and reaction ability. REFERENCES Papadopoulos, C., Salonikidis, K. & Schmiedtbleicher, D. (1997). Diagnose and Auswertung der motorischen Fahigkeiten Kraft und Schnelligkeit bei Kindern im alter swischen 10-15 Jaren. (in press). Schmiedtbleicher, D. (1994) Entwicklung der Kraft und Schnelligkeit. In J. Bauer et al. (Hrsg.) Motorische EntwicMung, Ein Handbuch. Verlag Hofmann Schorndorf Beitrage zur Lehre und Forschung im Sport, Band 106:129-150.
Coaching and Sports Activities
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