A qualitative analysis of soft tissue artefact during running

Soft tissue artefact (STA) is the denomination used in the field of movement analysis to designate the relative movement between the skin markers and the underlying bones. This movement is of high amplitude and affects the estimate of bone pose. STA can be described with different definitions: individual marker displacements, markercluster geometrical transformations or skin envelope shape variations (Dumas et al. 2014). All definitions provide quantitative and qualitative information that may be useful to develop an STA model embedded in bone pose estimators. The architecture of the model and the number of parameters involved are essential for that purpose. In the literature, the main reported information is the amplitude of skin marker displacements (Peters et al. 2010). More qualitatively, some studies have shown that the rigid transformations of the marker-cluster are more important than deformations (Andersen et al. 2012; Grimpampi et al. 2013). One study shows some consistency in the STA inter-subject pattern (Barre et al. 2013). The objective of this study is to analyse qualitatively the information about the STA during running. The individual marker displacements, marker-cluster geometrical transformations, and skin envelope shape variations are ranked to describe the main patterns of shank and thigh STA.