Morphology of a swimmer influences the external resistance to forward motion (hydrodynamic resistance). The torso represents the largest body mass segment and characteristics such as cross-sectional area perpendicular to the direction of swimming and curvatures and indentations influence the pressure distribution of fluid as it flows around the torso. The purpose of this study was to introduce a new method of quantifying torso shape using photographic imaging. The contours of the torso in the frontal and sagittal planes were obtained by tracing photographs of the swimmers taken from the front and side respectively. The anterior, posterior and lateral flow lines outlines were interpolated to samples spaced at 1mm vertically and used to determine continuous form gradients of four elite male swimmers. Cross sectional areas of the torso at each vertical sample were estimated by modelling the cross section as an ellipse. The maximum rate of change in cross-sectional area (m2) was then estimated from chest to waist and waist to hip. The method may be used detect differences in torso shape between swimmers in a practical and ‘user friendly’ manner. The implications and direction for future research to determine the influence of the torso on hydrodynamic resistance in free swimming and in the streamlined body position are described.
|Title of host publication||International Society of Biomechanics|
|Publication status||Accepted/In press - 14 Mar 2019|
- Fluid dynamics
- Drag force