Balancing Deceit and Disguise: How to successfully fool the defender in a 1 vs. 1 situation in rugby
Résumé
Changing direction suddenly requires a whole body reorientation strategy. In sporting duels such as an attacker versus a defender in rugby, successful body orientation/reorientation strategies are key to successful performance. The aim of this study is to see which biomechanical factors, whilst taking into account biomechanical constraints, are used by an attacker in a 1 vs. 1 duel in rugby. More specifically we wanted to see how an attacker tries to deceive the defender yet disguise his intentions by comparing effective deceptive movements (DM+), ineffective deceptive movements (DM-) and non-deceptive movements (NDM). Eight French amateur expert rugby union players were asked to perform DMs and NDMs in a real 1 vs. 1 duel. For each type of movement (DM+, DM-, NDM) different relevant orientation/reorientation parameters, medio-lateral displacement of the centre of mass (COM), foot, head, upper trunk and lower trunk yaw; and upper trunk roll were analysed and compared. Results showed that COM displacement and lower trunk yaw were minimised during DMs whilst foot displacement along with head and upper trunk yaw were exaggerated during DMs (DM+ and DM-). This would suggest that the player is using exaggerated body-related information to consciously deceive the defender into thinking he will run in a given direction whilst minimising other postural control parameters to disguise a sudden change in posture necessary to modify final running direction. Further analysis of the efficacy of deceptive movements showed how the disguise and deceit strategies needed to be carefully balanced to successfully fool the defender.