Gender differences in head impacts sustained by collegiate ice hockey players

Abstract

Purpose: This study aimed to quantify the frequency, magnitude, and location of head impacts sustained by male and female collegiate ice hockey players during two seasons of play.

Methods: During two seasons, 88 collegiate athletes (51 females, 37 males) on two female and male National Collegiate Athletic Association varsity ice hockey teams wore instrumented helmets. Each helmet was equipped with six single-axis accelerometers and a miniature data acquisition system to capture and record head impacts sustained during play. Data collected from the helmets were postprocessed to compute linear and rotational accelerations of the head as well as impact location. The head impact exposure data (frequency, location, and magnitude) were then compared between genders.

Results: Female hockey players experienced a significantly lower (P < 0.001) number of impacts per athlete exposure than males (females = 1.7 ± 0.7, males = 2.9 ± 1.2). The frequency of impacts by location was the same between genders (P > 0.278) for all locations except the right side of the head, where males received fewer impacts than females (P = 0.031). Female hockey players were 1.1 times more likely than males to sustain an impact less than 50 g, whereas males were 1.3 times more likely to sustain an impact greater than 100 g. Similarly, males were 1.9 times more likely to sustain an impact with peak rotational acceleration greater than 5000 rad·s(-2) and 3.5 times more likely to sustain an impact greater than 10,000 rad·s(-2).

Conclusions: Although the incidence of concussion has typically been higher for female hockey players than male hockey players, female players sustain fewer impacts and impacts resulting in lower head acceleration than males. Further study is required to better understand the intrinsic and extrinsic risk factors that lead to higher rates of concussion for females that have been previously reported.

Figure 1

The Head Impact Telemetry (HIT) System was used to record frequency, location, and severity of head impacts in ice hockey. Left: Inside view of an Easton S9 equipped with an instrumented helmet unit (IHU). Right: A rink-side antennae connected to a laptop computer actively communicates with IHU to collect and process impact data received via radio transmitter.

Figure 2

Impacts were separated into four generalized location groups based on recorded azimuth (θ) and elevation (α). Top impacts include all impacts with elevation 65° or higher. Front, Back, and Side regions were separated into four equally distributed 90° regions as shown with the left and right sides combined into a single Side location. Used by permission, courtesy of Greenwald et al.(20)

Figure 3

Male hockey players sustained more head impacts than their female counterparts per season and per Athlete Exposure (p<0.001).

Figure 4

Distributions of impacts by peak linear and rotational acceleration were non-normally distributed towards low magnitude impacts for both males and females; however, males sustained head impacts with higher peak linear and rotational acceleration more frequently than females.