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Biomechanics

Neuromuscular and Brain Biomechanics

Development of an Impact Performance Test Method for the Evaluation of Bull Riding Helmets

Saturday, October 14, 2023
12:45 PM – 1:00 PM PDT
Location: 334 (Center, Level 3)
Introduction::


Bull-riding was deemed the most dangerous sport by the International Sportmed Journal in 2007 [1], seeing 21 fatalities between 1989 and 2009 [2]. Despite this, there are few commercially available helmets designed specifically for bull-riding. While limited epidemiological rodeo injury studies suggest that helmet use can prevent fatalities caused by head impacts [2], it is still unclear whether existing helmets adequately protect against non-fatal head injuries, including traumatic and mild traumatic brain injuries (TBI and mTBI). In 2017, the sport saw its first confirmed case of chronic traumatic encephalopathy (CTE) by suicide, a neurodegenerative disease caused by repeated TBI or mTBI [3]. This case of CTE in a rider who typically wore a helmet suggests that it is critical to include concussion-relevant impacts in the evaluation of bull riding helmets. Our research aims to develop a comprehensive impact testing method that replicates head rotation to accurately characterize the impact performance of bull riding helmets. In this study, a new test method is proposed, and preliminary data is presented that compares the impact performance of helmets currently used in bull riding.






Materials and Methods::


ASTM F2530 (the existing bull-riding helmet testing standard) and NOCSAE ND081- 18am20 (a general linear impactor helmet testing standard) were used to develop a bull-riding helmet testing method that simulated impacts from bull kicks. A Cadex Pneumatic Linear Impactor was used in combination with a Hybrid III 50th percentile male head form with a coplanar 6aɷ accelerometer array (2000 g, DTS; 18k deg/sec, DTS; 2000 g, Endevco) fixed at the head form center of gravity. These accelerometers measure head kinematics to calculate two injury metrics: rotational acceleration and head injury criterion (HIC). The helmeted head form was subjected to sixteen 5.0 m/s impacts per helmet type that alternated between two location sets containing two of the six modified locations based on NOCSAE ND081-18am20. Each location set was impacted using both a flat and pointed hoof-shaped anvil that are in accordance with ASTM F2530. Two helmets per helmet type were subject to a series of two 5 m/s impacts, one at each testing location with either the pointed or flat anvil. Eight CCM Tacks 110 helmets, and eight Bauer IMS 5.0 Hockey helmets were evaluated. Helmet safety was then assessed by the change in HIC values between the two helmet types, anvils, and locations.






Results, Conclusions, and Discussions::


The HIC values generated from the linear accelerations are shown in Figure 1. A HIC value of 250 has been shown to lead to concussions in impact sports [4], which was not reached or exceeded by any of the impacts evaluated in this study. When subject to the same test conditions, impacts using the flat anvil resulted in significantly higher HIC values. Additionally, the side and rear location set showed significantly higher HIC values at 5 m/s. Front cage deformation was observed in three helmets impacted with the flat anvil at the front and front boss locations. The average relative performance of each helmet type at a 5 m/s velocity was dependent on impact location and impacting anvil, with neither helmet type experiencing a HIC value of 250. It is suggested that both helmet types are effective in preventing potentially concussive events. To further investigate the performance of the respective helmet types, additional testing is needed at the remaining locations as well as impacts at an increased velocity of 7.5 m/s.






Acknowledgements (Optional): :


Thanks to the Clemson College of Agriculture, Forestry and Life Sciences and the Clemson Honors College for support of the study and the Robert Brooks Sports Science Institute for research funding.






References (Optional): :


[1] Brandenburg, M.A., Int. J. Sportsmed., 2007, 8, 78-86. [2] Butterwick, D.J., Clin. J. Sport Med., 2011, 21, 243-248. [3] Wright, D.K., Sci Rep, 2019, 9. [4] Viano, D.C., SMIA, 2005, 124, 121-130.