Relationship Among Upper, Middle, and Lower Thoracic Vertebrae and Upper and Lower Lumbar Vertebrae in Dancers During Arabesque.

Background: Low back pain is a common disorder with high severity among dancers. Since Arabesque used in dance is more likely to cause lower back pain, it is important to prevent the onset of lower back pain during arabesque. Previous studies are investigating motion of the lumbar vertebrae during various tasks in targeting dancers. However, since the thoracic and lumbar vertebrae are connected, it is necessary to assess including motion of the thoracic spine. The purpose of this study was to clarify the relationship between the upper, middle, and lower thoracic vertebrae and the upper and lower lumbar vertebrae in dancers during arabesque. Methods: The participants were 13 university students with dance experience, and they performed double-standing and arabesque tasks. During the tasks, the positions of reflective markers attached to the spine (upper, middle, and lower thoracic vertebrae, and upper and lower lumbar vertebrae) were measured using a three-dimensional motion analysis system. The amount of change in the spinal angle of during standing and arabesque were calculated based on positions of spinal markers, and the relationship between the amount of change each spinal region (6 pairs) were analyzed by using Pearson's correlation test. Results: A significant negative correlation was observed between the amount of change in the angle of the middle thoracic vertebrae and the amount of change in the upper lumbar vertebrae (r = -.66, P = .013), which means that as the movement of the middle thoracic vertebrae increases, the movement of the upper lumbar vertebrae decreases. No significant correlation was observed between other spinal angles (P > .05). Conclusion: The results of this study suggest that increasing mobility in the middle thoracic vertebrae may be able to prevent hyperextension of the upper lumbar vertebrae, leading to the prevention of upper back pain in dancers.