other protective conditions, including unprotected (no headgear/facemask, as a “baseline”) and a hockey-style catcher’s mask. Methods The overall test assembly consisted of a Hybrid III 50th percentile male head/neck assembly mounted on a set of low-friction, linear rails. A pneumatic cannon, consisting
John Strickland and Grant Bevill
Abigail M. Tyson, Stefan M. Duma and Steven Rowson
/m 2 . 44 A medium National Operating Committee on Standards for Athletic Equipment (NOCSAE) headform custom fit with a Hybrid III neck was mounted on a linear slide table with 5 degrees of freedom. 44 , 45 Three linear accelerometers (7264b-2000; Endevco, Irvine, CA) and a triaxial angular rate
Steven Rowson, Jonathan G. Beckwith, Jeffrey J. Chu, Daniel S. Leonard, Richard M. Greenwald and Stefan M. Duma
The high incidence rate of concussions in football provides a unique opportunity to collect biomechanical data to characterize mild traumatic brain injury. The goal of this study was to validate a six degree of freedom (6DOF) measurement device with 12 single-axis accelerometers that uses a novel algorithm to compute linear and angular head accelerations for each axis of the head. The 6DOF device can be integrated into existing football helmets and is capable of wireless data transmission. A football helmet equipped with the 6DOF device was fitted to a Hybrid III head instrumented with a 9 accelerometer array. The helmet was impacted using a pneumatic linear impactor. Hybrid III head accelerations were compared with that of the 6DOF device. For all impacts, peak Hybrid III head accelerations ranged from 24 g to 176 g and 1,506 rad/s2 to 14,431 rad/s2. Average errors for peak linear and angular head acceleration were 1% ± 18% and 3% ± 24%, respectively. The average RMS error of the temporal response for each impact was 12.5 g and 907 rad/s2.
Erin Hanlon and Cynthia Bir
Soccer heading has been studied previously with conflicting results. One major issue is the lack of knowledge regarding what actually occurs biomechanically during soccer heading impacts. The purpose of the current study is to validate a wireless head acceleration measurement system, head impact telemetry system (HITS) that can be used to collect head accelerations during soccer play. The HIT system was fitted to a Hybrid III (HIII) head form that was instrumented with a 3-2-2-2 accelerometer setup. Fifteen impact conditions were tested to simulate impacts commonly experienced during soccer play. Linear and angular acceleration were calculated for both systems and compared. Root mean square (RMS) error and cross correlations were also calculated and compared for both systems. Cross correlation values were very strong with r = .95 ± 0.02 for ball to head forehead impacts and r = .96 ± 0.02 for head to head forehead impacts. The systems showed a strong relationship when comparing RMS error, linear head acceleration, angular head acceleration, and the cross correlation values.
Jonathan G. Beckwith, Jeffrey J. Chu and Richard M. Greenwald
Although the epidemiology and mechanics of concussion in sports have been investigated for many years, the biomechanical factors that contribute to mild traumatic brain injury remain unclear because of the difficulties in measuring impact events in the field. The purpose of this study was to validate an instrumented boxing headgear (IBH) that can be used to measure impact severity and location during play. The instrumented boxing headgear data were processed to determine linear and rotational acceleration at the head center of gravity, impact location, and impact severity metrics, such as the Head Injury Criterion (HIC) and Gadd Severity Index (GSI). The instrumented boxing headgear was fitted to a Hybrid III (HIII) head form and impacted with a weighted pendulum to characterize accuracy and repeatability. Fifty-six impacts over 3 speeds and 5 locations were used to simulate blows most commonly observed in boxing. A high correlation between the HIII and instrumented boxing headgear was established for peak linear and rotational acceleration (r 2 = 0.91), HIC (r 2 = 0.88), and GSI (r 2 = 0.89). Mean location error was 9.7 ± 5.2°. Based on this study, the IBH is a valid system for measuring head acceleration and impact location that can be integrated into training and competition.
Brooklynn M. Knowles, Henry Yu and Christopher R. Dennison
Wearable kinematic sensors can be used to study head injury biomechanics based on kinematics and, more recently, based on tissue strain metrics using kinematics-driven brain models. These sensors require in-situ calibration and there is currently no data conveying wearable ability to estimate tissue strain. We simulated head impact (n = 871) to a 50th percentile Hybrid III (H-III) head wearing a hockey helmet instrumented with wearable GForceTracker (GFT) sensors measuring linear acceleration and angular velocity. A GFT was also fixed within the H-III head to establish a lower boundary on systematic errors. We quantified GFT errors relative to H-III measures based on peak kinematics and cumulative strain damage measure (CSDM). The smallest mean errors were 12% (peak resultant linear acceleration) and 15% (peak resultant angular velocity) for the GFT within the H-III. Errors for GFTs on the helmet were on average 54% (peak resultant linear acceleration) and 21% (peak resultant angular velocity). On average, the GFT inside the helmet overestimated CSDM by 0.15.
Patricia M. Kelshaw, Trenton E. Gould, Mark Jesunathadas, Nelson Cortes, Amanda Caswell, Elizabeth D. Edwards and Shane V. Caswell
impacts to the head. Our testing procedures only allotted for linear acceleration outcomes. Research suggests that rotational acceleration is likely a contributor to concussion incidence. 22 Although rotational acceleration has also been shown to correlate with PLA 23 – 25 in humans and Hybrid III test
Srinidhi Bellamkonda, Samantha J. Woodward, Eamon Campolettano, Ryan Gellner, Mireille E. Kelley, Derek A. Jones, Amaris Genemaras, Jonathan G. Beckwith, Richard M. Greenwald, Arthur C. Maerlender, Steven Rowson, Stefan M. Duma, Jillian E. Urban, Joel D. Stitzel and Joseph J. Crisco
for use in football . J Appl Biomech . 2011 ; 27 ( 1 ): 8 – 14 . PubMed ID: 21451177 doi:10.1123/jab.27.1.8 10.1123/jab.27.1.8 21451177 39. Beckwith JG , Greenwald RM , Chu JJ . Measuring head kinematics in football: correlation between the head impact telemetry system and Hybrid III