THE RELATIONSHIP BETWEEN KlNEMATlC VARIABLES AND SHOOTING DISTANCE IN BASKETBALL: A RE-EVALUATION
AbstractINTRODUCTION The majority of studies which consider the kinematics of basketball shooting have either analysed technique for shots from a single distance (e.g. Hudson, 1985), or have compared technique across two distances (e.g. Elliott, 1989). Whilst such methods allow comparison of kinematic variables at the distance(s) investigated, they do not permit conclusions to be drawn with respect to their relationships over a range of distances. This is because for a case in which there are only two levels of independent variable, the only possible interpretation of its relationship with dependent variables is linear. The objective of this study was to investigate the relationship between various kinematic parameters and shooting distance using a wide range of distances. METHODS Three dimensional video techniques (50 Hz) were used to record basketball jump shots from a range of distances (0.9- 8.5 m), as performed by members of the men's quarter-finalist teams at the XVI World University Games. Eighteen sequences were digitised from 20 frames prior to take-off to 10 frames after release. Shooting distances were established by comparison with court markings. RESULTS The correlation between the square of release speed and shooting distance yielded a value of r = 0.90 (p < 0.01), which is consistent with theoretical predictions. The correlation between release speed and angular velocity of the elbow joint of the shooting arm at release (r = 0.75, p c 0.01) led to the expectation that the latter would approximate a quadratic relationship with shooting distance. This was indeed the case, especially for shooting distances greater than 3 m. Despite previous findings of no difference when using ANOVA on a three group design, a negative correlation (r = -0.68, p < 0.01) was found between shooting distance and angular displacement of the elbow of the shooting arm at release, suggesting a decrease in the latter as shooting distance increases. No relationship was found between release angle and shooting distance, despite previous reports to the contrary, which seemed to be due to the effects of changes in release heights with respect to shooting distance in the current study. CONCLUSIONS It was concluded that ascertaining the true nature of relationships between kinematic variables and distance can be problematic when using only two values of the latter, and that as many shooting distances as possible should be incorporated into research designs. Ascertaining the true nature of such relationships will provide more accurate information with respect to the required modifications to the kinematics of shooting at different distances. REFERENCES Elliott, Band White, E. (1989). A kinematic and kinetic analysis of the female two point and three point jump shots in basketball. The Australian Journal of Science and Medicine in Sport, 21,7-11. Hudson, J.L. (1 985). Prediction of basketball skill using biomechanical variables. Research Quarterly for Exercise and Sport. 56,115-1 21 .
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