Rugby Science Update 6
The role of player mass and contact speed on head kinematics and neck dynamics in rugby union tackling
This study aimed to use multi- body modeling simulations to examine how tackler and ball carrier mass and contact speed affect inertial head kinematics and neck dynamics. Simulations were run by independently varying the ball carrier and tackler mass (from 60 to 110kg) and speed (from 0 to 10 m/s). Peak resultant inertial neck dynamics (force and moment) and head kinematics (linear acceleration, angular acceleration, and angular velocity) were extracted from each simulation. The study found that the greatest inertial head kinematics and neck dynamics were sustained by a lighter player during a tackle with a heavier player, irrespective of their role as a tackler or ball carrier. For contact speed, the greatest inertial head kinematics and neck dynamics sustained by the ball carrier and tackler were when they were both traveling at the highest speed.
This study was published in the Scandinavian Journal of Medicine & Science in Sports.
Tackle technique and changes in Playerload™ during a simulated tackle: an exploratory study
The aim of this study was to explore how PlayerLoad™ changes between different levels of tackling technique during a simulated tackle. PlayerLoad™ did not significantly differ between technical score categories at the point of contact. However, during the tackle completion phase, tackles within the high technical scoring category recorded a higher PlayerLoadTM than low and medium technical scoring tackles. The PlayerLoad™ trace of tackles within the high technical scoring category were also more consistent throughout the tackle. The variability in the PlayerLoad™ trace may be the consequence of players not shortening their steps before contact, reducing their ability to control their movement during the contact and post-contact phase of the tackle. Using the PlayerLoad™ trace in conjunction with technique assessments offers coaches and practitioners insight into the physical-technical relationship of each tackle to optimise tackle skill training, monitoring and match preparation.
This study was published in the Journal of Sports Science and Medicine and free to download.
Three-dimensional mechanics of the rugby tackle, does the ball carrier alter their movement into contact in response to the tackler’s position?
The aim of this exploratory study was to identify if, when, and how, the ball carrier modified their motion when being tackled, in response to specific tackle instructions given to the tackler. The ball carrier was observed to modify their behaviour in response to anticipated changes in the tackler’s motion. Specifically, the ball carrier positioned their body at contact using one of two movement strategies: (1) increasing their stability via flexing their trunk, knee, and hips more when entering mid or high trunk tackles; or (2) offload the ball or perform an evasive movement strategy by positioning themselves in a more upright body position when being tackled at a low trunk tackle height. These findings, together with knowledge of tackle injury-risk factors, could inform future coaching interventions for the ball carrier to optimise their performance and mitigate injury risk during the tackle.
This study was published in the International Journal of Sports Science and Coaching and is free to access.
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