Lee Herrington, Ian Horsley, Lindsey Whitaker and Christer Rolf
The objective of this study was to assess the effect of a simulated tackling task on shoulder joint position sense (JPS) in rugby players. The study also aimed to assess if differences in JPS occurred between mid range and end of range JPS, and if the tackling task had angle-specific effects on these values. JPS was assessed in 22 asymptomatic professional rugby union players.using two criterion angles in the 90Â° shoulder abduction position (45Â° and 80Â° external rotation) prior to and following a simulated tackling task. The results showed JPS to be significantly reduced following a fatiguing task. But this change was only true for the end of range position, with JPS in the mid range not changing. If the mechanoreceptors are unable to accurately report shoulder position in the outer range (stretch) position due to repetitive tackling, then there is a potential for the anterior structures to become stressed before any compensatory muscle contraction can take place.
This study highlights the presence of sensorimotor system deficits following repeated tackling and proposes that this may contribute to overuse injuries and micro-instability of the glenohumeral joint which may be related to the increasing rate of shoulder injuries in rugby.
Physical Therapy in Sport, 16 April 2008, online article ahead of print