Faculty Bibliography

Despite recent improvements in their concussion knowledge, athletes still demonstrate risky concussion behaviors (e.g., playing while concussed or not reporting a concussion). Little has been published about dancers' concussion knowledge and behaviors, but research in dance contending with questions about injury in general has found that dancers often avoid physician consults and ignore the signs of injury. In the present study, an IRB approved anonymous online survey, it was hypothesized that dancers would demonstrate concussion knowledge deficits, fail to report concussions, and have difficulty adhering to management guidelines. In addition, it was hypothesized that dancers in companies or schools with an onsite health care practitioner present would demonstrate improved concussion knowledge and safer concussion behaviors compared with those that do not have onsite health care. Concussion knowledge and behavior questions were modified for a dance sample based on validated sports-specific tools developed by other investigators. One hundred fifty-three subjects were recruited to complete the survey from an urban orthopaedic clinic specializing in dance medicine and via Facebook, email, and newsletter announcements. Dancers in this sample had good foundational knowledge of concussion; however, this knowledge did not correlate with safe, self-reported concussion care behaviors. Future research should focus on determination of dance-specific barriers to practicing safe behaviors and seeking care for concussive injury, as well as further identifying dance concussion epidemiology and outcomes.

BACKGROUND: Fatigue is strongly linked to an increased risk of injuries, including anterior cruciate ligament (ACL) ruptures. Part 1 of this study identified differences in the biomechanics of landing from a jump between dancers and team athletes, particularly female athletes, which may explain the epidemiological differences in ACL injuries between dancers and team athletes and the lack of a sex disparity within dancers. However, it is not known if these biomechanical variables change differently between team athletes and dancers in the face of fatigue. PURPOSE/ HYPOTHESIS: The purpose of this study was to compare dancers' and team athletes' resistance to fatigue and its effect on the biomechanics of single-legged drop landings. The primary hypotheses were that dancers may be more resistant than team athletes to the onset of fatigue and/or may have different biomechanical responses than athletes in landing tasks once fatigue has been achieved. STUDY DESIGN: Controlled laboratory study. METHODS: Kinematics and kinetics were recorded as 40 elite modern and ballet dancers (20 men and 20 women) and 40 team sport athletes (20 men and 20 women; National Collegiate Athletic Association Division I-III) performed single-legged drop landings from a 30-cm platform before and after a fatigue protocol consisting of step-ups and vertical jumps. Unfatigued and fatigued joint kinematics and kinetics were compared between groups and sexes with multivariate analyses of variance, followed by pairwise t tests as appropriate. RESULTS: Dancers took longer (P = .023) than team athletes to reach a similar state of fatigue. Multiple kinetic (eg, increased peak knee valgus moment; P < .001) and kinematic (eg, increased lateral and forward trunk flexion; P < .001 and P = .002, respectively) parameters of landing changed with fatigue, such that both fatigued dancers and athletes landed with mechanics that were more at risk for ACL injuries as compared with before fatigue. CONCLUSION: Dancers took significantly longer to reach fatigue than team athletes. Female athletes consistently exhibited landing patterns associated with a risk for ACL injuries when compared with the other 3 groups. Fatigue changed landing mechanics similarly in both dancers and athletes, such that all groups landed with worse alignment after being fatigued. CLINICAL RELEVANCE: Dancers are more resistant to lower extremity fatigue than athletes, and this may partially explain the lower incidence of ACL injuries in both male and female dancers compared to team athletes. The extensive training in landing technique and daily practice that dancers undergo from a young age may be responsible for the higher levels of endurance.