|
Abstract
|
OBJECTIVE: 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.
DESIGN: Repeated measures. SETTING: University human performance laboratory. PARTICIPANTS: Twenty-two asymptomatic professional rugby union players. MAIN OUTCOME MEASURES: JPS was assessed using two criterion angles in the 90 degrees shoulder abduction position (45 degrees and 80 degrees external rotation) prior to and following a simulated tackling task.
RESULTS: Prior to the tackling task JPS (absolute error scores) was worse at the 45 degrees than 80 degrees criterion angle (p<0.05). Following the tackling task absolute error scores were significantly increased at the 80 degrees angle (p<0.001), with no significant change at the 45 degrees angle (p>0.05), and no significant difference was present for error scores between angles (p=0.74).
CONCLUSIONS: This study found 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. These results highlight the presence of sensorimotor system deficits following repeated tackling. These deficits are proposed to contribute to overuse injuries and micro-instability of the glenohumeral joint which may be related to the increasing rate of shoulder injuries in rugby.
Language: en |