Relationship between core stability and shoulder injuries in athletes

Core stability (neuromuscular control and muscle capacity of the trunk and pelvis) is theoretically linked to optimal shoulder function during sports-specific tasks despite limited evidence to support its use for the prevention or rehabilitation of extremity injuries in athletes. Impairments in core stability could theoretically result in less than optimal performance and abnormal force dissipation to the shoulder complex that could potentially lead to upper extremity injuries in athletes. Lower extremity postural control is also associated with athletic function and may be associated with upper extremity injuries. Clinical measures of core stability have not been validated against lab-based measures of core neuromuscular control. This has resulted in several knowledge gaps that hinder clinical identification of core stability deficits in athletes, as well as the determination of the role that core stability has in athletic injuries. The specific aims of this study are to 1) determine the strength of the association between clinical and lab-based measures of core stability in the athletic population and 2) identify the clinical and lab-based measures of core stability that are significant predictors of shoulder injuries in athletes. Eighty athletes (55 males, age: 21.2 + 3.3 years, 40 with shoulder pain) completed clinical and lab-based tests of core stability that assess aspects of both muscle capacity and neuromuscular control of the trunk and pelvis, as well as lower extremity postural stability. Athletes competed at a club, varsity, or competitive level, and were matched by age, gender, BMI, and sport type. Spearman's rho ([rho]) correlations were used to assess relationships between clinical and biomechanical measures of core stability. MANOVAs were used to assess differences between measures of core stability and lower extremity postural stability between groups. There were significant small-medium correlations between clinical and biomechanical measures of core stability. There were no statistically significant differences between athletes with and without shoulder injuries for the clinical or biomechanical core stability measures or clinical or biomechanical lower extremity postural stability measures. Our findings suggest that the clinical tests assessed require some static core neuromuscular mechanisms, although these tests primarily assess of core muscle capacity. Although core stability is widely incorporated in rehabilitation of athletes with shoulder injuries, these athletes may not present with impairments in core stability or lower extremity postural stability.