Joint hypermobility as a predictor of mechanical loading in dancers

Context: Dance requires the performance of complex movements that may exceed normal anatomical range however in hypermobile individuals this may have implications for injury and performance. Objectives: The aim of the study was to investigate the efficacy of the Beighton score (BS) in predicting mechanical loading in dancers in hypermobile and non-hypermobile dancers with consideration of accelerometer placement and lumbar flexion hypermobility. Design: Cohort study, clinical measurement. Setting: University. Participants: Thirty-four dancers had their joint hypermobility assessed by the BS. Participants completed the Dance Aerobic Fitness Test (DAFT) with a Global positioning device incorporating a triaxial accelerometer located at the cervico-thoracic junction (C7) and one at the mid belly of the gastrocnemius. Main outcome measures: Accelerometry data was used to calculate PlayerLoad total, PlayerLoad medial-lateral, PlayerLoad anterior-posterior and Player Load vertical. Physiological response was measured via heart rate and fatigue response by rate of perceived exertion. Results: The total BS was a poor predictor of all mechanical loading directions with PlayerLoad anterior posterior C7 (r = .15) and PlayerLoad total lower limb (r = .20) the highest values. Multiple linear regression was a better predictor with values of C7 (r = .43) and lower limb (r = 0.37). No significant difference existed between hypermobile and non-hypermobile subjects for mechanical loading values for all stages of the DAFT and for heart rate and fatigue responses. Conclusions: The BS is not a good predictor of mechanical loading which is similar in hypermobile and non-hypermobile dancers for all levels of the DAFT. Mechanical loading and fatigue responses are similar between hypermobile and non-hypermobile dancers.