Sex differences in neck strength and head impact kinematics in university rugby union players

ABSTRACT

Globally, over three million women participate in rugby union, yet injury prevention and training strategies are predominantly based on androcentric data. These strategies may have limited generalisability to females, given the cervical spine is more susceptible to whiplash and less adept at resisting inertial loading. A total of 53 university rugby union players (25 female, 28 male, 20.7 ± 1.8 years) had their isometric neck strength measured. Bespoke instrumented mouthguards were used to record the magnitude of head impact events in six female and seven male competitive matches. Mean female maximal isometric neck strength was 47% lower than male. Independent samples Mann–Whitney U tests showed no significant differences for peak linear head acceleration (female: median 11.7 g, IQR 7.9 g; male: median 12.5 g, IQR 7.0 g p=.23) or peak rotational head acceleration (female: median 800.2 rad·s⁻², IQR 677.7 rad·s⁻²; male: median 849.4 rad·s⁻², IQR 479.8 rad·s⁻²; p=.76), despite the mean male body mass being 24% greater than female. Coded video analysis revealed substantial differences in head-impact mechanisms; uncontrolled whiplash dominated >50% of all recorded female impact events and <0.5% in males. Direct head-to-ground impacts comprised 26.1% of female and 9.7% of male impacts, with whiplash occurring in 78.0% and 0.5%, respectively. Overall, the data provided in this study do not support the generalisation of male-derived training and injury-prevention data to female rugby athletes. These results suggest a considerable research effort is required to identify specific weakness of female rugby players and derive appropriate training, injury prevention and return to play protocols.

Highlights

• Video analysis revealed substantial differences in head-impact mechanisms, with uncontrolled whiplash dominating >50% of all recorded female impact events but rarely in males.

• Isometric neck strength was 47% lower in female players than males.

• Direct head-to-ground impacts accounted for 26.1% and 9.7% of female and male impacts, with whiplash occurring in 78.0% and 0.5%, respectively.

KEYWORDS:

• Biomechanics
• data
• gender
• injury & prevention
• technology

Acknowledgements

The authors would like to thank all participants, coaches and trainers involved in the data collection. We specifically thank Georgia Weall, Madeleine Wynn Jones and Victoria Hayden for their time collecting data and Professor Melitta McNarry for the co-supervision of authors TP and FP. We would also like to thank Keytree Ltd for the MSc scholarships of authors TP and FP and KESS II Wales for the MSc scholarships of FP. We would also like to thank Sports Wellbeing Analytics Ltd, Philtronics Ltd and Keytree Ltd for ongoing Protecht™ mouthguard technical support and all the research students and collaborators who have supported this effort.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by KESS II Wales MSc Scholarships.