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Cervical spine kinematics during machine-based and live scrummaging.
Adrien Cerrito1, Peter Milburn1, Clair Alston-Knox2
1a School of Allied Health Sciences , Griffith University , Gold Coast , Australia.
Journal of Sports Sciences
|February 20, 2019
Summary
Rugby players experience significantly more cervical spine flexion during live scrums compared to machine scrums. This suggests current scrum machines do not accurately replicate the real-world scrummaging motion.
Area of Science:
- Sports Biomechanics
- Rugby Union Safety
Background:
- Scrummaging in rugby union involves significant cervical spine loading.
- Previous kinematic studies often utilize machine-based scrummaging, which may not reflect actual game conditions.
Purpose of the Study:
- To compare cervical spine kinematics between machine-based and live scrummaging in rugby union front row players.
- To determine if current scrum machines accurately replicate the biomechanical demands of live scrummaging on the cervical spine.
Main Methods:
- Electromagnetic tracking of sensors on the head and thorax to measure cervical spine kinematics.
- Analysis of joint angles at "bind" and impact phases during both scrummaging conditions.
- Statistical comparison using a mixed-effects model within a Bayesian framework.
Main Results:
- Cervical spine flexion was significantly greater in live scrums (38°-50°) compared to machine scrums.
- Minimal differences were observed in lateral-flexion (5°-8°) and axial rotation (7°) between the two conditions.
- Current scrum machine designs do not fully replicate the cervical spine motion patterns of live scrummaging.
Conclusions:
- Live rugby union scrummaging imposes greater cervical spine flexion than simulated machine-based scrummaging.
- Findings from machine-based scrummaging studies may not be generalizable to competitive rugby union contexts.
- This highlights potential limitations in using scrum machines for injury prevention research and training.
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