A Kinematic Analysis of a Rugby Spin Pass

Abstract

Passing is a predominant skill in rugby and considered the most important skill in attack. The ability to spin pass accurately is also considered an indicator of performance. With such little research conducted on the rugby spin pass the main aim of this study was to identify the kinematic movements that define a good or bad pass. The second aim was to, objectively, identify the sequential process of movement. The third aim was to identify dynamical systems theory, when applied to the rugby spin pass. Three participants undertook ten static passes from their favoured and unfavoured hand to targets at eight and 12 metres away. Video and CODA motion analysis were used to quantify the ball speed at release and kinematic measures such as joint angles and joint angular velocity. Results indicate no angular difference between hit and miss trials. The dominant and non-dominant wrist angular rotations demonstrated the largest difference peaking at -13 and 28° respectively. However, on a basis of larger ball release velocities (Participant one 3.5 ± 0.8m/s, participant two 3.5 ± 0.7m/s, participant three 4.9 ± 0.5m/s) and a greater accuracy (participant one 30/40 hits, participant two 28/40 hits, participant three 35/40 hits), participant three was identified as skilled with participant one and two, unskilled. The skilled participant demonstrated angular differences, across all variables measured against the unskilled participant, suggesting there is a movement that is more likely to be successful. The main finding of the study was the identification of the pull motion towards the end of the movement. Previously the understanding of getting low during the passing movement were to increase stability and in turn increase accuracy. However, extension of the trunk beginning between 85-88% of the movement and continuing to increase in velocity till 100%, contradicts the stability theory due to the raise in height decreasing stability. The follow through movement did not occur as there was flexion of the elbows between 86-87% of the movement and continued to increase in velocity till 100% of the movement. It cannot be said at this stage in the research that dynamical systems theory is or is not applicable to the rugby pass due to the limitations of the study.