title: Interception of moving objects in karate: an experimental, marker-free benchmark.
abstract: BACKGROUND
  karate requires an optimal interception of the opponent's attack. Particularly in unconstrained situations, normal, untrained, subjects solve this problem adopting rather different solutions. It is currently unknown if karate as show a more uniform selection of interception schemes due to their special training.
  
  
  METHODS
  here we applied a 3D scanner to study the movement reproducibility of skilled karate as in a natural setup, using an unconstrained interception task. Six right handed karatekas and six controls participated to the study. 3D motion tracking data of the upper limbs were obtained using the Microsoft Kinect sensor, a real-time 3D scanner. The interception task consisted of intercepting and stopping a moving stick which was directed towards the side of the subject in two different positions (upper and lower).
  
  
  RESULTS
  the analysis of hand trajectories showed that the strategy of the movement was remarkably different between control subjects, whereas it was more uniform in karatekas. Moreover, we observed a significant difference in the variability of the interception point between control subjects and karatekas.
  
  
  CONCLUSIONS
  the results confirm the presence of individual idiosincratic behavior in interception tasks also in ecologically realistic situations, and that experience and training (as in karatekas) play an important role in the trajectory in interceptive tasks.
authors.affiliation: Medicine and Health Sciences, University of Molise, Italy.
authors.forename: Giada
authors.initials: G
authors.lastname: Romano
authors.affiliation: Medicine and Health Sciences, University of Molise, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Viggiano
keywords: eye-hand coordination; motion tracking; trajectory