Author(s): YIFAN, H., YIJIE, Z., WANTING, F., ZHANGWEI, H., Institution: BEIJING SPORT INSTITUTE: BEIJING SPORT UNIVERSITY, Country: CHINA, Abstract-ID: 971

INTRODUCTION:
The Spiral turn is one of the unique fundamental technical movements in Latin dance and also serves as an important link connecting various dance steps, such as the” Alemana” .As one of the key forms of rotational techniques in Latin dance, the Spiral turn is required to maintain high stability and rotational speed during movement in accordance with the scoring criteria of the World Dance Sport Federation (WDSF). Therefore, this study aims to analyze multiple biomechanical indicators of the Spiral turn movement, explore the correlations between these indicators and rotational speed as well as stability, and screen out the key factors significantly associated with high-quality movement performance.
METHODS:
The present study aims to systematically reveal the quantitative relationship between velocity performance and stability during the Spiral turn in Latin dance using three-dimensional motion capture and biomechanical analysis techniques. A Qualisys eight-camera 3D motion capture system combined with force platforms was used to collect kinematic and kinetic data from 18 professional Latin dancers who met the inclusion and exclusion criteria. All data were processed with Visual3D software. Correlation and regression analyses of multiple kinematic and kinetic variables were performed using Python.
RESULTS:
The results showed that:(1) There was a relatively high correlation between the minimum upper limb rotation angle and moment of inertia.For the left limb: minimum rotation angle (R² = 0.38);Regression equation: Moment of Inertia = 0.0077 × Minimum Left Limb Rotation Angle + 0.2758.For the right limb: minimum rotation angle (R² = 0.32);Regression equation: Moment of Inertia = 0.0103 × Minimum Right Limb Rotation Angle + 0.2849.
(2) Among the three dimensions of stability indices, there was a very strong positive correlation between VSI and DPSI (R² = 0.99), with a regression slope close to 1.Regression model: y = 0.9862 × VSI + 18.07.In addition, a relatively high correlation was found between RAR angular momentum contribution and the stability index DPSI (R² = 0.37);Regression model: y = 356.85 × RAR Angular Momentum Contribution − 29.47.The minimum right upper limb rotation angle also showed a relatively high correlation with DPSI (R² = 0.33);Regression model: y = 356.85 × Minimum Right Upper Limb Rotation Angle + 111.6564.
CONCLUSION:
Rotational speed can be improved by maintaining body verticality prior to rotation initiation, allocating as much ground reaction force as possible to the main supporting leg, keeping an appropriate standing width (i.e., a moderate distance between the right leg and the center of mass), and adopting a smaller shoulder-arm angle during rotation.
More stable rotation can be achieved by implementing a sufficient pre-swing angle before rotation initiation, maintaining vertical stability, generating adequate angular momentum—especially that provided by the main supporting leg—and reducing limb angles during the rotational phase.