Head injury potential and the effectiveness of headgear in women's lacrosse.

Over the past 10 years, lacrosse has grown increasingly popular, making it one of the fastest growing team sports in the country. Similar to other sporting activities, head injuries in lacrosse can and do occur, and the number of lacrosse-related head injuries has increased in recent years. In women's lacrosse, protective headgear is not required, but U.S. Lacrosse and the American Society for Testing and Materials are currently working to develop a headgear standard for the women's game. In the interim, some female lacrosse programs and individual players are wearing soft headgear during play. The effectiveness of this headgear is unknown. Testing was conducted to better understand the material properties of various types of headgear that may be used in lacrosse and the effect of this headgear on head impact response and head injury potential. For the evaluation of head impact response, an instrumented Hybrid III anthropomorphic test device (ATD) was impacted on the side of the head with lacrosse balls and the front and side of the head with a lacrosse stick. The linear and rotational impact response of the head and corresponding acceleration-based injury metrics are reported. Testing was then repeated with the ATD wearing different types of headgear. Tested headgear included a men's lacrosse helmet and two brands of commercially-available soft headgear. For the higher velocity ball impacts, there was no statistically-significant difference in the measured linear and rotational response of the head for the no headgear and soft headgear test conditions. For the lower velocity ball impacts, there was a small, yet statistically-significant, reduction in head linear acceleration for one of the soft headgears tested in comparison to the no headgear test condition, but there was not a statistically-significant difference in the rotational impact response with this headgear. These results indicate that the soft headgear would not be effective in reducing head injury potential during higher velocity ball impacts, such as ball speeds associated with shooting in women's lacrosse. The men's lacrosse helmet reduced both the linear and rotational response of the head for the higher and lower velocity ball impacts. Material testing showed that the padding in the hard helmet exhibited larger strain energy than the padding within the soft headgears when tested in compression. These results correlate with the larger reductions in head accelerations during ball impacts by the hard helmet. For the stick impacts, there were no statistically-significant differences in the lateral impact response of the head for the helmeted and soft headgear test conditions in comparison to the no headgear test condition, but there were statistically-significant, albeit small, differences in the frontal impact response of the head. The similar impact responses of the head during the stick impacts with and without headgear can be attributed to the relatively low severity of these impacts and the characteristics of the impactor.