How does the situation before a tackle influence a tackler's head placement in rugby union?: application of the decision tree analysis.

OBJECTIVES: Tacklers need to decide where to place their head based on the evasive manoeuvres of the ball-carrier and positional relationship with the ball-carrier before tackle. Therefore, it is difficult for tacklers to improve incorrect head placement at the moment of contact. Moreover, the characteristics prior to tackle have a relationship with the tackler's head placement. However, how situations lead to incorrect head placement remains unknown. The aim of this study was to identify pre-contact situations that lead to incorrect head placement by using decision tree analysis.
METHODS: Tackles leading to concussions were used to identify events that provoked injury using the video recordings of matches. Injury-free tackle was used as a control. All tackles were classified according to head placements and coded from seven pre-contact factors configured aspect of both tacklers and ball-carriers.
RESULTS: Three situations that led to incorrect head placement were identified. Evasive manoeuvres implemented by the ball-carrier significantly contributed to the head placement at the time of contact.
CONCLUSION: Our findings suggest that tacklers should keep their heads up to identify the movements of the ball-carrier, which might lead to tackling the head on the correct side at the moment of tackling and decrease the risk of tackler-related concussions. © Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.