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Viano D.C.,ProBiomechanics LLC | Withnall C.,Biokinetics and Associates Ltd. | Halstead D.,University of Tennessee at Knoxville | Halstead D.,Southern Impact Research Center
Annals of Biomedical Engineering | Year: 2012

Linear impact tests were conducted on 17 modern football helmets. The helmets were placed on the Hybrid III head with the neck attached to a sliding table. The head was instrumented with an array of 3-2-2-2 accelerometers to determine translational acceleration, rotational acceleration, and HIC. Twenty-three (23) different impacts were conducted on four identical helmets of each model at eight sites on the shell and facemask, four speeds (5.5, 7.4, 9.3, and 11.2 m/s) and two temperatures (22.2 and 37.8 °C). There were 1,850 tests in total; 276 established the 1990s helmet performance (baseline) and 1,564 were on the 17 different helmet models. Differences from the 1990s baseline were evaluated using the Student t test (p < 0.05 as significant). Four of the helmets had significantly lower HICs and head accelerations than the 1990s baseline with average reductions of 14.6-21.9% in HIC, 7.3-14.0% in translational acceleration, and 8.4-15.9% in rotational acceleration. Four other helmets showed some improvements. Eight were not statistically different from the 1990s baseline and one had significantly poorer performance. Of the 17 helmet models, four provided a significant reduction in head responses compared to 1990s helmets. © 2011 Biomedical Engineering Society.

Viano D.C.,ProBiomechanics LLC | Withnall C.,Biokinetics and Associates Ltd. | Wonnacott M.,Biokinetics and Associates Ltd.
Annals of Biomedical Engineering | Year: 2012

An instrumented Hybrid III head was placed in a Schutt ION 4D football helmet and dropped on different turfs to study field types and temperature on head responses. The head was dropped 0.91 and 1.83 m giving impacts of 4.2 and 6.0 m/s on nine different football fields (natural, Astroplay, Fieldturf, or Gameday turfs) at turf temperatures of -2.7 to 23.9 °C. Six repeat tests were conducted for each surface at 0.3 m (1′) intervals. The Hybrid III was instrumented with triaxial accelerometers to determine head responses for the different playing surfaces. For the 0.91-m drops, peak head acceleration varied from 63.3 to 117.1 g and HIC 15 from 195 to 478 with the different playing surfaces. The lowest response was with Astroplay, followed by the engineered natural turf. Gameday and Fieldturf involved higher responses. The differences between surfaces decreased in the 1.83 m tests. The cold weather testing involved higher accelerations, HIC 15 and delta V for each surface. The helmet drop test used in this study provides a simple and convenient means of evaluating the compliance and energy absorption of football playing surfaces. The type and temperature of the playing surface influence head responses. © 2011 Biomedical Engineering Society.

Viano D.C.,ProBiomechanics LLC | Withnall C.,Biokinetics and Associates Ltd. | Wonnacott M.,Biokinetics and Associates Ltd.
Annals of Biomedical Engineering | Year: 2012

The potential for mouthguards to change the risk of concussion was studied in football helmet impacts. The Hybrid III head was modified with an articulating mandible, dentition, and compliant temporomandibular joints (TMJ). It was instrumented for triaxial head acceleration and triaxial force at the TMJs and upper dentition. Mandible force and displacement were validated against cadaver impacts to the chin. In phase 1, one of five mouthguards significantly lowered HIC in 6.7 m/s impacts (p = 0.025) from the no mouthguard condition but not in 9.5 m/s tests. In phase 2, eight mouthguards increased HIC from +1 to +17% in facemask impacts that loaded the chinstraps and mandible; one was statistically higher (p = 0.018). Peak head acceleration was +1 to +15% higher with six mouthguards and 2-3% lower with two others. The differences were not statistically significant. Five of eight mouthguards significantly reduced forces on the upper dentition by 40.8-63.9%. Mouthguards tested in this study with the Hybrid III articulating mandible lowered forces on the dentition and TMJ, but generally did not influence HIC or concussion risks. © 2011 Biomedical Engineering Society.

Bourget D.,Defense R and D Canada Valcartier | Anctil B.,Biokinetics and Associates Ltd.
2011 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury | Year: 2011

Non-lethal capability sets, which include Kinetic Energy Non Lethal Weapons (KENLW), have been acquired by the Canadian Forces during the last years but their effects on human targets are not fully understood. This paper presents various methods to evaluate their safety aspects with the goal to minimize the occurrence of lethal or serious injuries produced by KENLW. Test methods to assess the blunt impact effects of KENLW on the eyes, face, skull and thorax are discussed.

Wonnacott M.,Biokinetics and Associates Ltd. | Withnall C.,Biokinetics and Associates Ltd.
SAE Technical Papers | Year: 2010

Current state of the art in Anthropometric Test Device (ATD) headform development does not include biofidelity of the mandible and the temporomandibular joint (TMJ). In order to investigate the protective aspects of mouth guards in relation to mild traumatic brain injury (mTBI) potential, a headform with an articulating mandible has been developed. The headform is based upon the 50% male Hybrid III and has a steel mandible with steel upper and lower dentition and a compliant TMJ structure. The headform may be instrumented with tri-axial C.G. accelerometers, and includes tri-axial force sensors at both left and right TMJ's as well as the upper dentition. Mandible force and displacement response under direct chin impact has been validated against cadaver corridors developed recently at Wayne State University. The headform was developed under sponsorship of the National Football League primarily to assess the capability of mouth guards to reduce concussion risk in helmeted American football impacts. However this headform may also have application to other fields, such as military and automotive towards mandible, TMJ and dentition injury prevention research. Copyright © 2010 SAE International.

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