Ambient head temperature and football helmet design

OBJECTIVEAmid the public health controversy surrounding American football, a helmet that can reduce linear and rotational acceleration has the potential to decrease forces transmitted to the brain. The authors hypothesized that a football helmet with an outer shell would reduce both linear and rotational acceleration. The authors’ objectives were to 1) determine an optimal material for a shock-absorbing outer shell and 2) examine the ability of an outer shell to reduce linear and/or rotational acceleration.METHODSA laboratory-based investigation was undertaken using an extra-large Riddell Revolution football helmet. Two materials (Dow Corning Dilatant Compound and Sorbothane) were selected for their non-Newtonian properties (changes in viscosity with shear stress) to develop an outer shell. External pads were attached securely to the helmet at 3 locations: the front boss, the side, and the back. The helmet was impacted 5 times per location at 6 m/sec with pneumatic ram testing. Two-sample t-tests were used to evaluate linear/rotational acceleration differences between a helmet with and a helmet without the outer shell.RESULTSSorbothane was superior to the Dow Corning compound in force reduction and recovered from impact without permanent deformation. Of 5 different grades, 70-duro (a unit of hardness measured with a durometer) Sorbothane was found to have the greatest energy dissipation and stiffness, and it was chosen as the optimal outer-shell material. The helmet prototype with the outer shell reduced linear acceleration by 5.8% (from 75.4g to 71.1g; p < 0.001) and 10.8% (from 89.5g to 79.8g; p = 0.033) at the side and front boss locations, respectively, and reduced rotational acceleration by 49.8% (from 9312.8 rad/sec2 to 4671.7 rad/sed2; p < 0.001) at the front boss location.CONCLUSIONSSorbothane (70 duro) was chosen as the optimal outer-shell material. In the outer-shell prototype helmet, the results demonstrated a 5%–10% reduction in linear acceleration at the side and front boss locations, and a 50% reduction in rotational acceleration at the front boss location. Given the paucity of publicly reported helmet-design literature and the importance of rotational acceleration in head injuries, the substantial reduction seen in rotational acceleration with this outer-shell prototype holds the potential for future helmet-design improvements.

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PHYSICAL TESTING OF POTENTIAL FOOTBALL HELMET DESIGN ENHANCEMENTS

10.15368/theses.2016.68 ◽

2016 ◽

Author(s):

Michael Jeremy Schuster

Keyword(s):

Football Helmet ◽

Physical Testing ◽

Helmet Design

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U.S. Navy head anthropometry for helmet design

PsycEXTRA Dataset ◽

10.1037/e575832012-003 ◽

1999 ◽

Author(s):

Mary E. Gross ◽

Bruce Bradtmiller

Keyword(s):

Helmet Design

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Airbag Helmet: Design and Analysis of Helmet Piezoelectric Accelerometer

Journal of Physics Conference Series ◽

10.1088/1742-6596/1593/1/012038 ◽

2020 ◽

Vol 1593 ◽

pp. 012038

Author(s):

Edward R. Lin

Keyword(s):

Piezoelectric Accelerometer ◽

Helmet Design

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Football Equipment Design Affects Face Mask Removal Efficiency

The American Journal of Sports Medicine ◽

10.1177/0363546504271753 ◽

2005 ◽

Vol 33 (8) ◽

pp. 1210-1219 ◽

Cited By ~ 30

Author(s):

Erik E. Swartz ◽

Susan A. Norkus ◽

Tom Cappaert ◽

Laura C. Decoster

Keyword(s):

Removal Efficiency ◽

Perceived Exertion ◽

Cutting Tools ◽

Face Mask ◽

Equipment Design ◽

Rating Of Perceived Exertion ◽

Spine Injury ◽

Success Rates ◽

Football Helmet ◽

Perceived Difficulty

Background Researchers have investigated the performance of face mask removal tools for spine injury management in football but not the effects of football equipment design. Hypotheses Various styles or designs of football helmet equipment (helmets, face masks, loop straps) affect face mask removal efficiency. A cordless screwdriver performs more efficiently than do cutting tools. Study Design Controlled laboratory study. Methods Nineteen certified athletic trainers were randomly assigned to group 1 (cordless screwdriver and the FM Extractor) or group 2 (cordless screwdriver and the Trainer's Angel). Subjects randomly performed face mask removal for 6 conditions composed of helmet (3), face mask (3), and loop strap (5) combinations. Time, head movement, perceived difficulty, and success rates were measured. Results Multiple significant differences were found in time, movement, and perceived difficulty between the 6 helmet equipment conditions. The Shockblocker loop strap was consistently superior in all variables regardless of the tool used or the helmet it was attached to. The cordless screwdriver created less movement (mean range from any one plane, 2.8°-13.3°), was faster (mean range, 42.1-68.8 seconds), and was less difficult (mean rating of perceived exertion range, 1.4-2.9) compared to cutting tools (ranges, 4.4°-18.4° in any one plane, 71-174 seconds, rating of perceived exertion, 2.8-7.7). Trial failure was more common with cutting tools than with the screwdriver. Conclusion Differences in football helmet equipment affect face mask removal. The cordless screwdriver is more efficient than the FM Extractor and Trainer's Angel. Clinical Relevance Professionals responsible for the care of football athletes must be knowledgeable in the types of equipment used and the best option available for effective airway access.

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Can helmet design reduce the risk of concussion in football?

Journal of Neurosurgery ◽

10.3171/2014.1.jns13916 ◽

2014 ◽

Vol 120 (4) ◽

pp. 919-922 ◽

Cited By ~ 71

Author(s):

Steven Rowson ◽

Stefan M. Duma ◽

Richard M. Greenwald ◽

Jonathan G. Beckwith ◽

Jeffrey J. Chu ◽

...

Keyword(s):

Head Impact ◽

Dartmouth College ◽

University Of Minnesota ◽

Head Impacts ◽

University Of Oklahoma ◽

Significant Difference ◽

Rule Changes ◽

Impact Data ◽

Collegiate Football ◽

Helmet Design

Of all sports, football accounts for the highest incidence of concussion in the US due to the large number of athletes participating and the nature of the sport. While there is general agreement that concussion incidence can be reduced through rule changes and teaching proper tackling technique, there remains debate as to whether helmet design may also reduce the incidence of concussion. A retrospective analysis was performed of head impact data collected from 1833 collegiate football players who were instrumented with helmet-mounted accelerometer arrays for games and practices. Data were collected between 2005 and 2010 from 8 collegiate football teams: Virginia Tech, University of North Carolina, University of Oklahoma, Dartmouth College, Brown University, University of Minnesota, Indiana University, and University of Illinois. Concussion rates were compared between players wearing Riddell VSR4 and Riddell Revolution helmets while controlling for the head impact exposure of each player. A total of 1,281,444 head impacts were recorded, from which 64 concussions were diagnosed. The relative risk of sustaining a concussion in a Revolution helmet compared with a VSR4 helmet was 46.1% (95% CI 28.1%–75.8%). When controlling for each player's exposure to head impact, a significant difference was found between concussion rates for players in VSR4 and Revolution helmets (χ2 = 4.68, p = 0.0305). This study illustrates that differences in the ability to reduce concussion risk exist between helmet models in football. Although helmet design may never prevent all concussions from occurring in football, evidence illustrates that it can reduce the incidence of this injury.

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Pneumatic Microextrusion-Based Additive Biofabrication of Polycaprolactone Bone Scaffolds: Part II – Investigation of the Influence of Polymer Flow Parameters

Volume 1: Additive Manufacturing; Advanced Materials Manufacturing; Biomanufacturing; Life Cycle Engineering; Manufacturing Equipment and Automation ◽

10.1115/msec2021-63412 ◽

2021 ◽

Author(s):

Mohan Yu ◽

Logan Lawrence ◽

Pier Paolo Claudio ◽

James B. Day ◽

Roozbeh (Ross) Salary

Keyword(s):

Mechanical Performance ◽

Research Work ◽

Biological Tissues ◽

Direct Write ◽

Bone Scaffolds ◽

Flow Parameters ◽

Material Deposition ◽

Flow Pressure ◽

Physical Phenomena ◽

Head Temperature

Abstract Pneumatic micro-extrusion (PME), a direct-write additive manufacturing process, has emerged as a high-resolution method for the fabrication of a broad range of biological tissues and organs. However, the PME process is intrinsically complex, governed by complex physical phenomena. Hence, investigation of the effects of consequential parameters would be an inevitable need. The goal of this research work is to fabricate biocompatible, porous bone tissue scaffolds for the treatment of osseous fractures, defects, and eventually diseases. In pursuit of this goal, the objective of this study is to investigate the influence of material deposition factors — i.e., (i) deposition head temperature, (ii) flow pressure, and (iii) infill pattern — on the mechanical performance of PME-fabricated bone scaffolds. It was observed that the deposition head temperature as well as the flow pressure significantly affected scaffold diameter (unlike scaffold height). In addition, material deposition rate increased significantly as a result of an increase in the deposition temperature; this phenomenon stems from a reduction in Polycaprolactone (PCL) viscosity. Furthermore, there was a direct correlation between the amount of deposited mass and scaffold stiffness. Overall, the results of this study pave the way for future investigation of PME-deposited PCL scaffolds with optimal functional properties for incorporation of stem cells toward the treatment of osseous fractures and defects.

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