Movement Variability of Professional Pool Billiards Players on Selected Tasks

Parameter values characterizing the motion of the cue during impact in pool billiards have been determined for selected shots. 20 elite players performed 18 predefined tasks comprising follow, draw, stop shots and breaks. 3D-kinematics were obtained using a motion analysis system comprising 8 cameras operating at 250 Hz and a high speed camera capturing with 5000 Hz. Longitudinal accelerations of the cue stick were recorded with 5 kHz using an accelerometer, mounted on the butt cap of the cue. Coefficients of variation for the parameter values obtained range from 3.9% (height of impact point of maximum follow shot) to 58.3% (elevation angle of 10-ball break). The average cue stick motion is basically non-accelerated (-0.060 +/- 0.508 ms-2) at ball impact for all of the tasks except for the breaks (3.918 +/- 0.164 ms-2). Despite the high number of DOF in the input configuration the tested pool billiard players achieved very similar outcomes.