Abstract
Background: Irish dance has evolved rapidly throughout the years in terms of its athleticism, technical skills and aesthetics. In terms of technique, dancers must land from large leaps onto a single leg, without flexing their knee or dropping their heel. In particular, turnout is a key element of this dance form which involves external rotation of the lower limb, and must be sustained during the high impact landings. Limited availability and use of external hip rotation means that most dancers use friction on the floor to hold their foot in an exaggerated turned out position. Turnout caused by floor friction in the absence of hip external rotation moments are likely to result in large internal rotation moments at the knee and ankle, therefore increasing the risk of injury. As a means to improve alignment and reduce injury risk, somatic practice was investigated; a field of study that focusses on reducing muscular tension, enhancing kinaesthetic awareness and improving musculoskeletal alignment. By investigating the application of somatic practice as a prospective training method, we aim to provide insight into potentially improving turnout mechanisms and reducing risk of injury.
Objectives: The primary objective was to establish the relationship between hip external rotation and the internal/external rotation moments of the a) ankle and b) knee. The secondary objective was to evaluate the effectiveness of a somatic practice intervention in bringing about increased hip external rotation, and therefore turnout.
Materials and Methods: Thirteen (12 female; 64.9 ± 10.3 kg; 22 ± 2 y) competitive and performance Irish dancers completed a six week Alexander technique and Ideokinesis training programme, comprising of six 2-hour sessions. These particular somatic methodologies were chosen due to their musculoskeletal premise. The programme was designed with the purpose to increase and utilise external rotation at the hip by releasing muscular tension and improving alignment of the whole body. Prior to the intervention, each participant performed a minimum of 10 flys (common Irish dance leap) onto a force plate whilst wearing reflective markers and while being recorded by a motion capture system. This data was analysed to evaluate hip rotation and knee and ankle internal/external rotation moments during an Irish dance landing. This procedure was repeated after completion of the programme.
Results and Discussion: Mean hip external rotation magnitude decreased as the landing of the fly reached maximum vertical force and was of a lower magnitude than reported from the literature (-10.9 degrees ± 2.4). A negligible correlation was found between hip rotation angle at maximum vertical force for both moments at the same time point. However, when comparing the difference between the hip rotation angle and the foot toe-out angle (foot progression) to the knee and ankle internal rotation moments at maximum vertical force, low positive correlations were found (r = .15 [knee], r = .20 [ankle], p = < .01). Following the somatic practice intervention, no statistical differences between sessions were found but a slight increase in hip external rotation was observed. There was a large range of differences in movement profiles between participants, as well as a variety of responses to the somatic practice sessions.
Conclusion: The aesthetic and technical demands of Irish dance are in contrast to safe mechanics, potentially increasing overuse injury risk. Maximising hip turnout during landing should decrease internal/external rotation moments, as long as hip turnout affords the dancer better alignment between the femur and the foot. Reducing angular deviation about the longitudinal axis in this manner could help to navigate the demands of the dance style without compromising the aesthetic quality of the dancer. Somatic practices have the potential to improve body alignment, as well as kinaesthetic awareness, but further study needs to be conducted in order to consolidate this.