Full Length ArticleKinematic patterns underlying disguised movements: Spatial and temporal dissimilarity compared to genuine movement patterns

- This study investigated the kinematic characteristics of disguised movements.
- Linear discriminability between disguised and non-disguised movements was more error-prone for the temporal in comparison to the spatial component.
- The spatial dissimilarities were higher for novices in comparison to experts.
- Highest spatial dissimilarities were found in end effector-specific and -unspecific body parts.
- Expertise in performing disguised movements depends mainly on keeping spatial dissimilarities as small as possible.

This study examined the kinematic characteristics of disguised movements by applying linear discriminant (LDA) and dissimilarity analyses to the motion data from 788 disguised and 792 non-disguised 7-m penalty throws performed by novice and expert handball field players. Results of the LDA showed that discrimination between type of throws (disguised vs. non-disguised) was more error-prone when throws were performed by experts (spatial: 4.6%; temporal: 29.6%) compared to novices (spatial: 1.0%; temporal: 20.2%). The dissimilarity analysis revealed significantly smaller spatial dissimilarities and variations between type of throws in experts compared to novices (p < 0.001), but also showed that these spatial dissimilarities and variations increased significantly in both groups the closer the throws came to the moment of (predicted) ball release. In contrast, temporal dissimilarities did not differ significantly between groups. Thus, our data clearly demonstrate that expertise in disguising one's own action intentions results in an ability to perform disguised penalty throws that are highly similar to genuine throws. We suggest that this expertise depends mainly on keeping spatial dissimilarities small. However, the attempt to disguise becomes a challenge the closer one gets to the action outcome (i.e., ball release) becoming visible.