| Musculoskeletal injuries can have damaging effects on sports and/or job performance, psychosocial factors, and an increased risk of musculoskeletal impairments later in life. Non-contact injuries, such as an ACL rupture or non-traumatic shoulder injury, account for nearly 40% of all injuries sustained during practices and 20% of injuries incurred during sanctioned games. Pre-participation movement screening has gained popularity in collegiate athletics and military personnel in efforts to identify poor performance and individuals potentially at increased risk of injury. Proposed risk factors for injury include impairments in regional stability (i.e. core stability), movement pattern efficiency, mobility, and symmetry. Impairments in any of these risk factors may influence force generation, transfer, and dissipation throughout the body, potentially increasing stress on segments and joints. Current movement screens provide limited assessment of core stability and upper extremity stability, movement pattern efficiency, and mobility. The purposes of this study were to: 1) describe a novel comprehensive performance-based movement system-screening tool (MSST), 2) determine the validity of common and novel clinical tests of core stability, 3) determine the psychometric properties of the MSST, 4) and determine the ability of the MSST to identify athletes with a current history of non-traumatic shoulder injury. Eighty athletes (40 with a current shoulder injury) completed the MSST and lab-based measures of isolated core stability. Findings demonstrated that none of the clinical tests of core stability within the MSST were moderately significantly correlated to our lab-based measures. Results of the exploratory factor analysis (EFA) revealed three of the four design constructs (proposed risk factors) over 7 factors, representing 63% of the variance accounted for within the MSST: movement pattern efficiency (lower extremity, dynamic lower extremity), regional stability (upper and lower extremity, trunk/pelvis, dynamic), and mobility (upper and lower extremity, trunk/pelvis). Individual test inter-rater reliability ranged from fair to perfect (kappa= 0.26 -- 1.00). Inter-rater reliability of the MSST composite score was excellent, ICC (2,1) = 0.94, 95% CI (0.91, 0.96). Athletes with non-traumatic shoulder injury (composite score = 56.5 +/- 5.9) scored significantly lower than healthy controls (composite score = 59.5 +/- 4.8) on the MSST (t = 2.43, p = 0.02, d = 0.54). Logistic regression revealed rotary stability, shoulder mobility dominant arm, and glenohumeral internal rotation deficit predicted whether or not an athlete had shoulder pain, chi2 = 14.37, df = 5, N = 81, p = 0.01. None of the clinical tests of core stability demonstrated acceptable construct validity (r > 0.3) for assessing core neuromuscular control in an athletic population. Assessments assumed to assess muscle capacity were not significantly correlated to our lab-based measures of isolated core neuromuscular control, suggesting they are assessing a different construct (muscle capacity). The results of the current study suggest the MSST may have adequate inter-rater reliability and construct validity for use in clinical settings. However, future work should be done to assess the test-retest reliability and predictive validity of the MSST. The MSST was able to discriminate performance differences in athletes with and without non-traumatic shoulder injury. To date, this is the first comprehensive movement screen used to address non-traumatic upper extremity injury in athletes. |
