Related Experiment Video
Updated: Nov 10, 2025

A Test Bed to Examine Helmet Fit and Retention and Biomechanical Measures of Head and Neck Injury in Simulated Impact
Published on: September 21, 2017
How does the situation before a tackle influence a tackler's head placement in rugby union?: application of the
Keita Suzuki1, Satoshi Nagai2, Koichi Iwai3
1Sports Research and Development Core, University of Tsukuba, Tsukuba, Japan.
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.
More Related Videos
Related Concept Videos
Survival Tree
Building a Survival Tree
Constructing a...
Decision Making: P-value Method
First, a specific claim about the population parameter is proposed. The claim is based on the research question and is stated in a simple form. Further, an opposing statement to the claim is also stated. These statements can act as null and alternative hypotheses: a null hypothesis would be a neutral statement while the alternative hypothesis can...
Taping Over Different Ground Profiles
Decision Making: Traditional Method
First, a specific claim about the population parameter is decided based on the research question and is stated in a simple form. Further, an opposing statement to this claim is also stated. These statements can act as null and alternative hypotheses, out of which a null hypothesis would be a...
Reason and Intuition

