Measures of Lower Body Strength as Predictors for Lower Extremity Injury Severity in Preprofessional Ballet Dancers / Jenna Finkelstein (2023)

Lower extremity injury is prevalent in preprofessional ballet populations and often results in periods of modified training or time fully off dance. Evidence in sport contexts suggests there is a relationship between injury and lower body strength, which can be measured through physical profiling tests. There are studies in dance populations that support a link between lower body strength and injury severity, but limited evidence exists among preprofessional ballet dancers. This case study investigated performance on two isometric lower body strength tests, single leg (SL) squat and SL standing plantarflexion (PF), and gender as predictors for lower extremity injury severity among preprofessional ballet dancers at the Royal Ballet School. Strength scores and lower limb injury records were analyzed from four academic years, 2019- 2023. A total of 141 participants met the inclusion criteria, with 75 identifying as male and 66 identifying as female. Overall, male students exhibited significantly higher relative strength scores on the right and left sides for both tests compared to female students. A total of 177 lower extremity injuries were identified, with the foot and ankle being the most common site of injury. An average of approximately 44 days were required for injured dancers to return to full dance participation, which was equated to the average injury severity in this study. Injury severity did not differ significantly between male and female students. Multiple linear regression analysis was conducted with SL squat scores, SL standing PF scores, and gender as predictors for lower extremity injury severity. The overall model was not significant and had weak explanatory power. Examining the predictors individually, the effect of SL standing PF performance on predicting lower extremity injury severity was negative and statistically significant, indicating that increased strength of the plantar flexor muscles predicted less time of activity modification following a lower limb injury. This finding supports the use of strength training to enhance calf strength and to mitigate the impact of lower limb injuries on training time. Future studies should be prospective in nature and could consider the contribution of year group (training level) or rate of force development to predicting lower extremity injury severity.