Evaluation of a Novel Device for Assessing Ballet Dancers' Functional Turnout

Despite various approaches to measuring ballet dancers' turnout, no standardized method for doing so has yet been estab- lished. Here a newly designed rotational goniometer (RGM) for assessing ballet dancers' functional turnout is evaluated. Twenty experienced female ballet dancers participated in the study. Measurements of the dancers' turnout were taken three times in each of the following conditions: 1. while standing on the RGM device (RGMT); 2. as if the participant was in a ballet class (CT); and 3. performing an active external rotation of the lower extremities in the supine position (AT). The angles obtained in the three trials in each condition were averaged and the results of the three conditions were compared. The mean angle of RGMT (RGMT_angle: 103.89° ± 15.2°) was significantly smaller than those of the CT (CT_angle: 128.7° ± 15.1°) and AT (AT_angle: 110.09° ± 17.6°) conditions (p < 0.05 and p < 0.01, respectively). The greatest angle (i.e., the CT_angle) is influenced by both friction and weightbearing. The AT_angle is released from weightbearing, unlike the RGMT_angle. Positive correlations were revealed between the RGMT_angle and the AT_angle (r = 0.78, p < 0.01) and between the RGMT_angle and the CT_angle (r = 0.57, p = 0.05). These findings demonstrate that the novel RGM device, characterized by elimination of friction and full weightbearing, is useful for assessing ballet dancers' functional turnout.