Trenton E. Gould

Investigation of Baseline Self-Report Concussion Symptom Scores

CONTEXT Self-reported symptoms (SRS) scales comprise one aspect of a multifaceted assessment of sport-related concussion. Obtaining SRS assessments before a concussion occurs assists in determining when the injury is resolved. However, athletes may present with concussion-related symptoms at baseline. Thus, it is important to evaluate such reports to determine if the variables that are common to many athletic environments are influencing them. OBJECTIVE To evaluate the influence of a history of concussion, sex, acute fatigue, physical illness, and orthopaedic injury on baseline responses to 2 summative symptom scales; to investigate the psychometric properties of all responses; and to assess the factorial validity of responses to both scales in the absence of influential variables. DESIGN Cross-sectional study. SETTING Athletic training facilities of 6 National Collegiate Athletic Association institutions. PATIENTS OR OTHER PARTICIPANTS The sample of 1065 was predominately male (n = 805) collegiate athletes with a mean age of 19.81 +/- 1.53 years. MAIN OUTCOME MEASURE(S) Participants completed baseline measures for duration and severity of concussion-related SRS and a brief health questionnaire. RESULTS At baseline, respondents reporting a previous concussion had higher composite scores on both scales (P <or= .01), but no sex differences were found for concussion-related symptoms. Acute fatigue, physical illness, and orthopaedic injury increased composite SRS scores on both duration and severity measures (P <or= .01). Responses to both scales were stable and internally consistent. Confirmatory factor analysis provided strong evidence for the factorial validity of the responses of participants reporting no fatigue, physical illness, or orthopaedic injury on each instrument. CONCLUSIONS A history of concussion, acute fatigue, physical illness, and orthopaedic injury increased baseline SRS scores. These conditions need to be thoroughly investigated and controlled by clinicians before baseline SRS measures are collected.

Characterization of mouthguard materials: Thermal properties of commercialized products

OBJECTIVES Several mechanisms have been purported to describe how mouthguards protect the orofacial complex against injury. As the properties needed for these mechanisms to be effective are temperature and frequency dependent, the specific aim of this study was to provide a comprehensive thermal characterization of commercial mouthguard materials. METHODS Five commercially representative thermoplastic mouthguard materials (Essix Resin, Erkoflex, Proform-regular, Proform-laminate, and Polyshok) were tested. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) techniques were implemented to measure thermal transitions and mechanical properties. Measurements were conducted three times per sample. One-way ANOVA and one-sample t-tests were used to test for differences between commercial products on selected mean thermal property values. RESULTS The DSC measurements indicated no differences between commercial materials for mean glass transition (p=0.053), onset melt (p=0.973), or peak melt (p=0.436) temperatures. Likewise, DMA measurements revealed no differences between commercial materials for the mean glass transition (p=0.093), storage modulus (p=0.257), or loss modulus (p=0.172) properties, respectively. The one-sample t-tests revealed that glass transition temperatures were different from intra-oral temperature (p<0.005) for all materials. SIGNIFICANCE Commercialized mouthguard materials are sensitive to repetitive heating and cooling cycles, prolonged thermal treatment, and have glass transitions well below their end-use intra-oral temperature. As such, these materials are functioning as elastomers and not optimal mechanical damping materials. Dental clinicians, healthcare practitioners, or end-users should be aware that these materials are at best problematic with respect to this protective mechanism.

Characterizations of a Quality Certified Athletic Trainer

CONTEXT Didactic proficiency does not ensure clinical aptitude. Quality athletic health care requires clinical knowledge and affective traits. OBJECTIVE To develop a grounded theory explaining the constructs of a quality certified athletic trainer (AT). DESIGN Delphi study. SETTING Interviews in conference rooms or business offices and by telephone. PATIENTS OR OTHER PARTICIPANTS Thirteen ATs (men = 8, women = 5) stratified across the largest employment settings (high school, college, clinical) in the 4 largest districts of the National Athletic Trainers? Association (2, 3, 4, 9). DATA COLLECTION AND ANALYSIS Open-ended interview questions were audio recorded, transcribed, and reviewed before condensing. Two member checks ensured trustworthiness. Open coding reduced text to descriptive adjectives. RESULTS We grouped adjectives into 5 constructs (care, communication, commitment, integrity, knowledge) and grouped these constructs into 2 higher-order constructs (affective traits, effective traits). CONCLUSIONS According to participants, ATs who demonstrate the ability to care, show commitment and integrity, value professional knowledge, and communicate effectively with others can be identified as quality ATs. These abilities facilitate the creation of positive relationships. These relationships allow the quality AT to interact with patients and other health care professionals on a knowledgeable basis that ultimately improves health care delivery. Our resulting theory supported the examination of characteristics not traditionally assessed in an athletic training education program. If researchers can show that these characteristics develop ATs into quality ATs (eg, those who work better with others, relate meaningfully with patients, and improve the standard of health care), they must be cultivated in the educational setting.

Investigation of linear impact energy management and product claims of a novel American football helmet liner component

The pursuit to abate sport-related concussion necessitates thorough evaluation of protective technologies and product claims. Therefore, the purpose of this investigation was to: (i) define the linear impulse and compression behavior of the Aware-Flow shock absorber (the primary energy managing component of Xenith X1 football helmet); (ii) characterize resultant force–time curves utilizing compressive loading behavior of foam materials; and (iii) verify and define published findings and product claims. Absorbers (N = 24) from three adult X1 football helmets were impacted at predefined velocities of 1.3, 2.3, 3.0, 4.0, and 4.7 m·s− 1. Linear impulsive forces were ideally managed up to 3.0 m·s− 1 (25.4 J). The foam-filled pad improved impact energy attenuation and increased velocity-specific durability. The leptokurtic region of the 4.0 and 4.7 m·s− 1 impulse curves substantiated a third phase, defined as densification, as demonstrated by the maximum compression height approaching 90%. The adoption of elastic-plastic foam terminology was recommended based upon examination of the shock absorber design and resultant phased force-time curves. Results validated published findings on the prototype thin-walled collapsible air-filled chamber component and substantiated velocity-specific support for Aware-Flow shock absorber product claims.

Impact Properties of Thiol-Ene Networks

In this study, a series of thiol-ene networks having glass transition temperatures ranging from -30 to 60 °C were synthesized utilizing several multifunctional thiols and two trifunctional alkenes. Thermomechanical properties were determined using dynamic mechanical analysis, and impact properties were determined using pendulum impact and drop impact testing protocols. The impact behavior was found to directly correlate to the glass transition temperature, except when the temperature at which the impact event occurs overlaps with the range of temperatures corresponding to the viscoelastic dissipation regime of the polymer. Additionally, we discuss insight into the spatial limitations of energy dissipation for thiol-ene network polymers and establish a platform for predictability in similar systems.

Mechanical ageing performance of minimalist and traditional footwear foams

The aim of this study was to obtain a fundamental understanding of how running shoe midsole foam thickness contributes to footwear degradation using the heel and forefoot regions of traditional (TS) and minimalist (MS) running shoes. We hypothesized that ethylene vinyl acetate (EVA) foam midsole material properties and footwear degradation performance under a biofidelic mechanical ageing protocol would differ as a function of shoe type and thickness. Attenuated total reflectance Fourier transform infrared spectra indicated that the foam chemical compositions were similar and confirmed that all midsoles were composed of EVA copolymer. Differences in density and cell size were detected between shoes and thicknesses. MS foam was uniformly high density (ρMS = 240 kg/m3), while TS foam consisted of two co-molded layers with forefoot density (ρTS-FF = 250 kg/m3) greater than heel (ρTS-H = 160 kg/m3). Relative density and cell size values were generally proportional and inversely proportional to density, respectively. Degradation from mechanical ageing was greatest in the first 2 km of ageing, with the full ageing (21 km) resulting in an average 54% loss of energy absorption. Regardless of shoe type or foam microstructure, thicker and softer heel foams absorbed 83% more energy but degraded at a 49% faster rate. The fact that the heel degraded more rapidly than forefoot caused the drop to decrease at an equivalent rate for both shoe types. Overall, thickness was a greater predictor of average performance than microstructure variables for the present footwear conditions. However, the apparent drawback of thicker foam was exemplified by heel samples, which underwent a 1.4 mm greater loss of thickness and lost 550 mJ more energy absorption than forefoot samples.

National Athletic Trainers' Association Position Statement: Preventing and Managing Sport-Related Dental and Oral Injuries.

OBJECTIVE To provide athletic trainers, health care professionals, and all those responsible for the care of athletes with clinical recommendations for preventing and managing sport-related dental and oral injuries. BACKGROUND Participation in competitive sports continues to grow at both the interscholastic and intercollegiate levels. Therefore, exposure to, and the incidence of athletic-related injury, including orofacial injury, will also likely increase. At the time of this writing, the leading governing agencies for interscholastic (National Federation of State High School Associations) and intercollegiate (National Collegiate Athletic Association) sports require only protective orofacial equipment (eg, mouthguards) for 5 and 4, respectively, of their sanctioned sports. Although orofacial injuries represent a small percentage of all sport-related injuries, the financial burden associated with these injuries (eg, tooth avulsion) can exceed

Quantifying the effects of accelerated weathering and linear drop impact exposures of an American football helmet outer shell material

15 000 over an adult life. Therefore, effective management of sport-related dental injuries is critical to the long-term financial, physical, and emotional health of people who have experienced dental trauma. RECOMMENDATIONS Based upon the current evidence regarding sport-related orofacial injury, we provide recommendations related to planning considerations, education, and mouthguard efficacy, material, fabrication, and care considerations. Additionally, suggested best practices for managing sport-related dental injury are also given for athletic trainers and other health care professionals.

Biofidelic mechanical ageing of ethylene vinyl acetate running footwear midsole foam

American football helmets are subjected seasonally to a myriad of environmental conditions from expected use and storage and yet are reused without a relational understanding between service life degradation and changes in impact performance. Comprehensive investigations could link rates and degrees of material degradation to scientifically and clinically meaningful changes in helmet performance. Therefore, the purpose of this research was to preliminarily quantify the effects of accelerated weathering on (1) colorimetric, chemical, fluorescent, and thermal properties; (2) surface and bulk mechanical properties; and (3) impact performance of an American football helmet outer shell material. Helmet-grade plaques were exposed to 480 h of accelerated weathering. Surface-specific shifts (p < 0.05) in colorimetric, chemical, fluorescent, thermal, and mechanical properties were observed at the plaque surface. Plaque-derived tensile specimens underwent monotonic tensile testing, and the photodegraded ∼1% of the Weathered plaque surface thickness led to 10%, 12%, and 9% increases (p < 0.05) in Young’s modulus, yield stress, and ultimate tensile stress, respectively. Impact performance was analyzed with a protocol attempting to employ expected on-field impact conditions. Weathered and Non-weathered helmet surrogate systems managed impact energy progressively less effectively across five repetitive trials (p < 0.05); yet the absence of significant Weathered differences demonstrated that the plaque–foam systems performed similarly. Results identified a battery of diagnostic tools to characterize the degradation of outer shell material exposed to accelerated weathering. Thus, the comprehensive approach herein may be used toward the evaluation of additional service life exposures, as well as examine on-field deterioration of full helmet outer shells.

Protective headgear for sports

Simple manipulation of force–time input is a potential strategy to increase the biofidelity of running footwear mechanical ageing. The purpose of this study was to compare a Dwell protocol, which incorporated a recovery period characteristic of the float phase of running, to traditional sinusoidal ageing. A second aim was to use the protocol to compare the mechanical ageing performance of foam, a halved commercial running shoe, and a cylindrical plug cut from a running shoe to quantify effects due to testing geometry and to estimate the contribution of midsole foam to shoe energy management. Dwell was more biofidelic and less aggressive than Sine because (1) net displacement and energy absorption were greater than Sine and (2) net displacement and energy absorption decreased at a slower rate than Sine. Using a 60 mm diameter cylindrical plug to estimate the performance of a halved shoe with 100 mm contact area led to 20% overestimation of energy absorption. Comparing the performance of a slab of foam and a cylindrical plug cut out from a shoe, the midsole was estimated to manage 90% of the energy. Differences between sample types were also related to stiffness, yield behavior, and resulting hysteresis curve shapes, which revealed that the outsole improved sample deformation and durability. Overall, results supported that Dwell improved the biofidelity of mechanical ageing, testing geometry is an important consideration in experimental design, and most of the energy was managed by the midsole.