A Retrospective Analysis of the Pre-Season Screen Used in a Professional Ballet Company with Recommendations for Improvements in the Screen

摘要

Objectives: The primary objective was to determine if the current pre-season screen used by the Nashville Ballet was identifying dancers at risk for injury and determining the injury rates and patterns of injury within the company. The secondary purpose of this study is to propose more objective measurement tools to enhance the pre-season screen. Background: Professional ballet dancers are at an increased risk for lower extremity injuries. Dance USA developed a pre-season health screen intended to identify medical or musculoskeletal conditions that may limit a dancer’s ability to participate. Methods: Past screen history from the 2007-2014 seasons was obtained from 285 medical records. The ability of the established pre-season screen to predict injury among the injured dancers was determined by noting side-to-side differences specifically in the manual muscle tests and functional movement analysis portions of the screen. In 2015, seventeen professional dancers from the Nashville Ballet (11 female and 6 male) were included in the study. Manual muscle testing was performed using hand dynamometry on the gluteus maximus and gluteus medius muscles of each subject.3D motion analysis (MyoMotion) recorded dancers performing demi-plies on the right and left sides in parallel and in turnout. Paired samples t-tests were run with a Bonferroni correction and significance was set at p ≤ 0.05. Results: All injuries reported during the 2007-2014 seasons were in the lower extremity. Previous pre-season screen data showed the following: Manual muscle testing identified side-to-side gluteus medius differences in 26.92% (n = 26) and gluteus maximus side-to-side differences in 80% (n = 5) of injured dancers. Visual assessment of alignment while performing a plie in parallel and in turnout identified side-to-side differences in 23.08% and 26.92% respectively of the injured dancers. When assessing strength with the hand dynamometer, a significant difference was found between right and left gluteus maximus strength in percent body weight (p < 0.000) and right and left gluteus medius strength in percent body weight (p < 0.025). When assessing alignment using MyoMotion Kinematic Analysis, only right and left hip external rotation in turnout was found to be significant (p < 0.004). Conclusion: In this study, we observed that professional ballet dancers are at an increased risk for lower extremity injuries because the current pre-season screen used by professional ballet companies only identifies 25.64% of side-to-side differences. Adding more objective screening equipment such as the hand dynamometer and 3D motion analysis is recommended to improve the pre-season screen and to better identify dancers at risk for injury.