TITLE : A kinematic analysis of rugby

41 To characterise rugby union lineout throwing technique, three experienced 42 male rugby players performed throwing trials under varying conditions of 43 distance and trajectory. Motion analysis permitted the recovery of joint centre 44 coordinates at 120 Hz and the construction of a three-dimensional linked 45 segment model for calculation of joint angle and centre of mass time histories. 46 All participants exhibited greater accuracy at shorter throwing distances 47 although the accuracy decrement was less in players of superior playing level. 48 Participants demonstrated different technique alterations in order to perform 49 throws of longer distances; either showing increased magnitudes of upper 50 body joint angle velocities (less accurate thrower) or lower body joint velocities 51 (more accurate thrower). The most elite thrower exhibited greater consistency 52 in timing of peak joint angle velocities, with an overall standard deviation of 53 0.008 s compared with 0.027 s for the least accurate thrower. Data from 54 participants of lesser ability suggest that changes are made to both 55 magnitudes and timing of joint kinematics which leads to increased variability 56 in performance. Implications for players / coaches include the need to develop 57 core strength to permit limited changes to timing and magnitude of upper body 58 joint actions whilst allowing sufficient end-point velocity to be imparted on the 59 ball. 60