Basketball Free Throw








Fig. 1   Photo of eye movement sensor attached via a custom-fitted mount and placed on the visor of a subject.  The accelerometer bus assembly is worn on the elbow and hand.  Note the grid pattern in the background used for calibration of joint and ball positions.
























Fig. 2.   Trajectory of experimental free throw (*) and model simulation with () and without (--) lift, drag, and spin for the novice (top) and experienced (bottom) players.  Solid bar represents the basket.




Previous aerodynamic analysis has shown that the optimal release angle is in the range of 51 to 56 deg, and velocity is in the range of 20.5 to 25 ft/sec. Biomechanical analysis has shown the importance of bent elbows and knees, and a snap of the wrist at the moment of release.  This imparts the spin and consequent Magnus force that adds lift to the trajectory, increasing the range and the angle of entry.  Also, eye fixation on the rim is important for accuracy and consistency.  Our video, accelerometer, and eye movement measurements have demonstrated and verified these effects.  Moreover, the wireless device that has been developed can serve as a useful training tool to provide immediate feedback regarding the biomechanics of limb motions and eye fixation for optimal free throw performance.  Continued development of efficient wireless devices can provide detailed understanding of biomechanics and aerodynamics of the free throw under real-game conditions.  Further, this measurement technique can be applied to the study of athletic motions in other sports.


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This site was last updated 07/17/07