Exploring the gender divide: A multi-faceted study of head impact biomechanics, neurocognitive function, and cervical muscle strength

Principle Investigators: Jason P. Mihalik, PhD, CAT(C), ATC, Assistant Professor, (Principal Investigator); Stephen W. Marshall, PhD, Associate Professor, Department of Epidemiology (Co-investigator); Kevin M. Guskiewicz, PhD, ATC, Professor and Chair, Department of Exercise and Sport Science (Co-investigator).

Institution: The University of North Carolina, Department of Exercise and Sport Science.

Title: Exploring the gender divide: A multi-faceted study of head impact biomechanics, neurocognitive function, and cervical muscle strength.

Abstract:
Background:
Recent epidemiological evidence has suggested that female ice hockey players are at a higher risk of sustaining concussion during participation than their male counterparts. This is not intuitive given the women’s game does not involve active body checking. The literature is void of biomechanical injury data in this at-risk group of athletes. Further, how injury biomechanics manifests into clinical dysfunction following head trauma is also unexplored as growing evidence suggests sex differences in cognitive measures exist following concussion.

Aims:
To study sex differences in: 1) the biomechanics (frequency, location, and magnitude) of head impacts sustained by ice hockey players; 2) cervical muscle strength and the interactions between head impact severity and anticipation in mitigating head impact severity; 3) cumulative subconcussive impacts sustained over the course of each season on cognitive function; and 4) the interrelationships between impact severity, impact location, and neurocognitive measures following concussion.

Study Design:
A prospective study of head impact biomechanics and neurocognitive function.

Materials and Methods:
Three female hockey teams (U19, U16, U14) from a local hockey association will be matched by age to three male teams (U18, U16, U14) (total N=100 players per year). These six teams each participate in a 50+ game season. Our preliminary injury data from male teams suggests the observed incidence will be 2-3 concussions per team per season. Over the course of the study period, we anticipate observing no less than 24 concussions. Prior to the start of the first season, preseason baseline measures (computerized and traditional neurocognitive tests, postural stability tests, mental status exams, and cervical muscle strength) will be recorded. Players will be properly fit with helmets instrumented with the Head Impact Telemetry (HIT) System. Players’ head impacts will be monitored during every practice and game over the course of the two-year study period. When a player sustains a concussion, they will undergo a neuropsychological evaluation. Further, athlete-exposures will be recorded and injury rates will be determined.

Main Outcome Measures:
Biomechanical measures of head impact severity (linear acceleration, rotational acceleration, Head Impact technology severity profile – HITSP); clinical measures of concussion; cervical muscle strength.

Significance:
Female ice hockey players have been shown to have higher injury rates than their male counterparts. Our understanding of the reasons for this difference is hampered by a lack of data. Explanations to this have been limited at best in the literature. This study offers us the opportunity to compare head impacts in a 3-team female cohort with an age-matched male cohort. Measures of cervical muscle strength will be recorded at periodic times during the season, and video footage will add to our understanding of collision anticipation on reducing head impact severity in young hockey players, with a particular emphasis on how female hockey players differ from males. Understanding the differences between males and females in these respects will allow us to develop better injury prevention programs targeted for these specific populations.