RESUMEN
The inertial properties of a helmet play an important role in both athletic performance and head protection. In this study, we measured the inertial properties of 37 football helmets, a National Operating Committee on Standards for Athletic Equipment (NOCSAE) size 7» headform, and a 50th percentile male Hybrid III dummy head. The helmet measurements were taken with the helmets placed on the Hybrid III dummy head. The center of gravity and moment of inertia were measured about six axes (x, y, z, xy, yz, and xz), allowing for a complete description of the inertial properties of the head and helmets. Total helmet mass averaged 1834±231 g, split between the shell (1377±200 g) and the facemask (457±101 g). On average, the football helmets weighed 41±5% as much as the Hybrid III dummy head. The center of gravity of the helmeted head was 1.1±3.0 mm anterior and 10.3±1.9 mm superior to the center of gravity of the bare head. The moment of inertia of the helmeted head was approximately 2.2±0.2 times greater than the bare head about all axes.
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Fútbol Americano , Dispositivos de Protección de la Cabeza , Fenómenos Mecánicos , Ensayo de MaterialesRESUMEN
Previous studies on neck muscle strength and motion have assumed or imposed varying constraints on the heads and bodies of the subjects. In this study, we asked 20 subjects to vigorously shake their heads 5-10 times in a completely unconstrained manner. The kinematics and kinetics of the head and neck were measured from video analysis and instrumentation mounted inside the mouth. Subjects shook their heads at self-selected tempos ranging from 1.9-4.7 Hz over a 20-91° range of motion. The motion of each subject's head could be approximated by a fixed center of rotation that was typically located in the midcervical spine, but varied widely among subjects. Significant differences between men and women were observed. Peak head accelerations were low (4.3 ± 1.1 g and 250 ± 103 rad/s2 for men, 3.0 ± 0.9 g and 182 ± 58 rad/s2 for women) and estimated peak generated neck moments at C7/T1 were comparable to values reported in isometric neck strength studies (47 ± 14 N·m in extension and 22 ± 9 N·m in flexion for men, 25 ± 8 N·m in extension and 9 ± 7 N·m in flexion for women).
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Aceleración , Movimientos de la Cabeza/fisiología , Cuello/fisiología , Esfuerzo Físico/fisiología , Rango del Movimiento Articular/fisiología , Adulto , Femenino , Humanos , Modelos Biológicos , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Physical reconstructions are a valuable methodology for quantifying head kinematics in sports impacts. By recreating the motion of human heads observed in video using instrumented test dummies in a laboratory, physical reconstructions allow for in-depth study of real-world head impacts using well-established surrogates such as the Hybrid III crash test dummy. The purpose of this paper is to review all aspects of the physical reconstruction methodology and discuss the advantages and limitations associated with different choices in case selection, study design, test surrogate, test apparatus, text matrix, instrumentation, and data processing. Physical reconstructions require significant resources to perform and are therefore typically limited to small sample sizes and a case series or case-control study design. Their accuracy may also be limited by a lack of dummy biofidelity. The accuracy, repeatability, and sensitivity of the reconstruction process can be characterized and improved by good laboratory practices and iterative testing. Because wearable sensors have their own limitations and are not available or practical for many sports, physical reconstructions will continue to provide a useful and complementary approach to measuring head acceleration in sport for the foreseeable future.
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Aceleración , Fútbol Americano , Humanos , Fenómenos Biomecánicos , Cabeza , Dispositivos de Protección de la Cabeza , Examen FísicoRESUMEN
The use of head kinematic measurement devices has recently proliferated owing to technology advances that make such measurement more feasible. In parallel, demand to understand the biomechanics of head impacts and injury in sports and the military has increased as the burden of such loading on the brain has received focused attention. As a result, the field has matured to the point of needing methodological guidelines to improve the rigor and consistency of research and reduce the risk of scientific bias. To this end, a diverse group of scientists undertook a comprehensive effort to define current best practices in head kinematic measurement, culminating in a series of manuscripts outlining consensus methodologies and companion summary statements. Summary statements were discussed, revised, and voted upon at the Consensus Head Acceleration Measurement Practices (CHAMP) Conference in March 2022. This manuscript summarizes the motivation and methods of the consensus process and introduces recommended reporting checklists to be used to increase transparency and rigor of future experimental design and publication of work in this field. The checklists provide an accessible means for researchers to apply the best practices summarized in the companion manuscripts when reporting studies utilizing head kinematic measurement in sport and military settings.
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Conmoción Encefálica , Humanos , Consenso , Revelación , Aceleración , Dispositivos de Protección de la Cabeza , Fenómenos Biomecánicos , CabezaRESUMEN
The biomechanics of ankle injury have been studied extensively, primarily through mechanical testing of human cadavers. Cadaveric testing is an invaluable methodology in biomechanics, because the magnitude and direction of the loading can be measured precisely and correlated with the resulting injury pattern. Clinical and epidemiological studies provide useful descriptions of injury patterns that occur in the real world, but their retrospective nature precludes a definitive analysis of the forces that caused the injury. Understanding the mechanism of ankle injuries is essential for developing countermeasures to prevent injury and for reconstructing injurious events. Knowledge of an injury's mechanism can also suggest potential associated injuries, which is helpful in diagnosis and treatment. The purpose of this review is to summarize the published research on ankle injury mechanisms with an emphasis on biomechanical experiments on human cadavers. Injury patterns are described based on the principal axis of force or torque producing the injury in conjunction with off-axis forces and out-of-plane foot positions. A mechanistic description of ankle injuries is complicated by the fact that the same mechanism can sometimes produce different injuries and the same injury can sometimes be caused by multiple mechanisms. Nonetheless, a framework for relating injury mechanisms and injury patterns is a valuable tool in the understanding, prevention, and treatment of ankle injuries.
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Traumatismos del Tobillo/etiología , Cadáver , Articulación Talocalcánea/lesiones , Traumatología/métodos , Tobillo/diagnóstico por imagen , Tobillo/fisiopatología , Traumatismos del Tobillo/diagnóstico por imagen , Traumatismos del Tobillo/fisiopatología , Fenómenos Biomecánicos/fisiología , Humanos , Radiografía , Rango del Movimiento Articular , Articulación Talocalcánea/diagnóstico por imagen , Articulación Talocalcánea/fisiopatologíaRESUMEN
The Guardian Cap NXT (GC NXT) and the ProTech Helmet Cap (ProTech) are commercially available aftermarket products designed to augment the energy attenuation characteristics of American football helmets. The ability of these helmet shell add-on products to mitigate the severity of impacts typically experienced by professional offensive and defensive linemen was evaluated for seven helmet models using two test series. In linear impactor tests, the GC NXT reduced head impact severity as measured by the head acceleration response metric (HARM) by 9% relative to the helmets only, while the ProTech reduced HARM by 5%. While both products significantly improved the performance of the football helmets tested overall, effects varied by impact condition and helmet model with the add-ons worsening helmet performance in some conditions. The GC NXT had a strong effect size (Cohen's d = 0.8) whereas the ProTech had a medium effect (Cohen's d = 0.5). A second study investigated add-on performance for helmet-to-helmet impacts with eccentric impact vectors and resulted in a mixture of increased and decreased HARM when either add-on was placed on one or both helmets. Estimated risk for serious neck injury with add-ons and without differed by less than 4% for these eccentric impacts.
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Fútbol Americano , Dispositivos de Protección de la Cabeza , Equipo Deportivo , Aceleración , Traumatismos en Atletas/prevención & control , Traumatismos Craneocerebrales/prevención & control , Diseño de Equipo , Fútbol Americano/lesiones , Humanos , Ensayo de Materiales , Rotación , Estados UnidosRESUMEN
Seventeen concussive helmet-to-helmet impacts occurring in National Football League (NFL) games were analyzed using video footage and reconstructed by launching helmeted crash test dummies into each other in a laboratory. Helmet motion on-field and in the laboratory was tracked in 3D before, during, and after impact in multiple high frame rate video views. Multiple (3-10) tests were conducted for each of the 17 concussive cases (100 tests total) with slight variations in input conditions. Repeatability was assessed by duplicating one or two tests per case. The accuracy of the input conditions in each reconstruction was assessed based on how well the closing velocity, impact locations, and the path eccentricity of the dummy heads matched the video analysis. The accuracy of the reconstruction output was assessed based on how well the changes in helmet velocity (translational and rotational) from the impact matched the video analysis. The average absolute error in helmet velocity changes was 24% in the first test, 20% in the tests with the most accurate input configuration, and 14% in the tests with minimal error. Coefficients of variation in 22 repeated test conditions (1-2 per case) averaged 3% for closing velocity, 7% for helmet velocity changes, and 8% for peak head accelerations. Iterative testing was helpful in reducing error. A combination of sophisticated video analysis, articulated physical surrogates, and iterative testing was required to reduce the error to within half of the effect size of concussion.
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Conmoción Encefálica , Fútbol Americano/lesiones , Dispositivos de Protección de la Cabeza , Modelos Biológicos , Grabación en Video , Aceleración , Adolescente , Adulto , Fenómenos Biomecánicos , Conmoción Encefálica/patología , Conmoción Encefálica/fisiopatología , Conmoción Encefálica/prevención & control , Cabeza/patología , Cabeza/fisiopatología , Humanos , MasculinoRESUMEN
Sports concussions offer a unique opportunity to study head kinematics associated with mild traumatic brain injury. In this study, a model-based image matching (MBIM) approach was employed to analyze video footage of 57 concussions which occurred in National Football League (NFL) games. By utilizing at least two camera views, higher frame rate footage (> 60 images s-1), and laser scans of the field and helmets involved in each case, it was possible to calculate the change in velocity of the helmet during impact in six degrees of freedom. The average impact velocity for these concussive events was 8.9 ± 2.0 m s-1. The average changes in translational and rotational velocity for the concussed players' helmets were 6.6 ± 2.1 m s-1 and 29 ± 13 rad s-1, respectively. The average change in translational velocity was higher for helmet-to-ground (n = 16) impacts compared to helmet-to-helmet (n = 30) or helmet-to-shoulder (n = 11) events (p < 0.001), while helmet-to-shoulder impacts had a smaller change in rotational velocity compared to the other impact sources (p < 0.001). By quantifying the impact velocities and locations associated with concussive impacts in professional American football, this study provides information that may be used to improve upon current helmet testing methodologies.
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Acelerometría , Conmoción Encefálica , Fútbol Americano/lesiones , Dispositivos de Protección de la Cabeza , Grabación en Video , Adulto , Conmoción Encefálica/patología , Conmoción Encefálica/fisiopatología , Conmoción Encefálica/prevención & control , Cabeza/patología , Cabeza/fisiopatología , Humanos , Masculino , Estados UnidosRESUMEN
The relationship between laboratory and on-field performance of football helmets was assessed for 31 football helmet models selected from those worn by players in the 2015-2019 National Football League (NFL) seasons. Linear impactor tests were conducted with helmets placed on an instrumented Hybrid III head and neck assembly mounted on a sliding table. Based on impacts to each helmet at six impact locations and three velocities, a helmet performance score (HPS) was calculated using a linear combination of the head injury criterion (HIC) and the diffuse axonal multi-axis general evaluation (DAMAGE). To determine the on-field performance of helmets, helmet model usage, player participation, and incident concussion data were collected from the five NFL seasons and used to calculate helmet model-specific concussion rates. Comparison of laboratory HPS to the helmet model-specific concussion rates on a per play basis showed a positive correlation (r2 = 0.61, p < 0.001) between laboratory and on-field performance of helmet models, indicating that helmets which exhibited reduced impact severity in the laboratory tests were also generally associated with lower concussion rates on-field. Further analysis showed that NFL-prohibited helmet models exhibited a significantly higher odds of concussion (OR 1.24; 95% CI 1.04-1.47; p = 0.017) relative to other helmet models.
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Aceleración , Conmoción Encefálica/prevención & control , Fútbol Americano/lesiones , Dispositivos de Protección de la Cabeza , Conmoción Encefálica/fisiopatología , Cabeza/fisiopatología , Humanos , Estados UnidosRESUMEN
As more is learned about injury mechanisms of concussion and scenarios under which injuries are sustained in football games, methods used to evaluate protective equipment must adapt. A combination of video review, videogrammetry, and laboratory reconstructions was used to characterize concussive impacts from National Football League games during the 2015-2017 seasons. Test conditions were generated based upon impact locations and speeds from this data set, and a method for scoring overall helmet performance was created. Head kinematics generated using a linear impactor and sliding table fixture were comparable to those from laboratory reconstructions of concussive impacts at similar impact conditions. Impact tests were performed on 36 football helmet models at two laboratories to evaluate the reproducibility of results from the resulting test protocol. Head acceleration response metric, a head impact severity metric, varied 2.9-5.6% for helmet impacts in the same lab, and 3.8-6.0% for tests performed in a separate lab when averaged by location for the models tested. Overall inter-lab helmet performance varied by 1.1 ± 0.9%, while the standard deviation in helmet performance score was 7.0%. The worst helmet performance score was 33% greater than the score of the best-performing helmet evaluated by this study.
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Conmoción Encefálica , Dispositivos de Protección de la Cabeza , Modelos Biológicos , Aceleración , Conmoción Encefálica/patología , Conmoción Encefálica/fisiopatología , Conmoción Encefálica/prevención & control , Fútbol Americano , Cabeza/patología , Cabeza/fisiopatología , Humanos , Masculino , Rotación , Estados UnidosRESUMEN
Consideration of position-specific features of the NFL concussion environment could enable improved risk mitigation through the design of position-specific helmets to improve self-protection as well as protection for the other player with whom the contact occurs. The purpose of this paper is to quantify position-specific features of scenarios resulting in concussions to NFL players, and the players they contact, by reviewing all game footage (broadcast and non-broadcast) over 4 seasons. Position-specific features were documented for 647 concussions in which a primary exposure could be visualized, including impact source, helmet impact location, activity, and the other player with whom the contact occurred. Findings include the over-representation of helmet-to-ground impacts to the rear of the quarterback's helmet, the high frequency of impacts to the side (upper) location of both concussed players and the players they contacted regardless of position, and distinct differences in the circumstances of concussions to cornerbacks and safeties. The study shows that some features of concussion scenarios are common to all positions, but several position-specific features exist and can inform the design of position-specific helmets for NFL players.
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Conmoción Encefálica , Fútbol Americano/lesiones , Dispositivos de Protección de la Cabeza , Estaciones del Año , Conmoción Encefálica/fisiopatología , Conmoción Encefálica/prevención & control , Cabeza/fisiopatología , Humanos , MasculinoRESUMEN
In this study, twenty volunteers were subjected to three, non-injurious lateral head impacts delivered by a 3.7 kg padded impactor at 2 m/s at varying levels of muscle activation (passive, co-contraction, and unilateral contraction). Electromyography was used to quantify muscle activation conditions, and resulting head kinematics were recorded using a custom-fit instrumented mouthpiece. A multi-modal battery of diagnostic tests (evaluated using neurocognitive, balance, symptomatic, and neuroimaging based assessments) was performed on each subject pre- and post-impact. The passive muscle condition resulted in the largest resultant head linear acceleration (12.1 ± 1.8 g) and angular velocity (7.3 ± 0.5 rad/s). Compared to the passive activation, increasing muscle activation decreased both peak resultant linear acceleration and angular velocity in the co-contracted (12.1 ± 1.5 g, 6.8 ± 0.7 rad/s) case and significantly decreased in the unilateral contraction (10.7 ± 1.7 g, 6.5 ± 0.7 rad/s) case. The duration of angular velocity was decreased with an increase in neck muscle activation. No diagnostic metric showed a statistically or clinically significant alteration between baseline and post-impact assessments, confirming these impacts were non-injurious. This study demonstrated that isometric neck muscle activation prior to impact can reduce resulting head kinematics. This study also provides the data necessary to validate computational models of head impact.
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Cabeza/fisiología , Músculos del Cuello/fisiología , Aceleración , Adolescente , Adulto , Fenómenos Biomecánicos , Encéfalo/diagnóstico por imagen , Electromiografía , Cabeza/anatomía & histología , Humanos , Imagen por Resonancia Magnética , Masculino , Cuello/anatomía & histología , Pruebas Neuropsicológicas , Equilibrio Postural , Adulto JovenRESUMEN
BACKGROUND: Head kinematics generated by laboratory reconstructions of professional football helmet impacts have been applied to computational models to study the biomechanics of concussion. Since the original publication of this data, techniques for evaluating accelerometer consistency and error correction have been developed. This study applies these techniques to the original reconstruction data and reanalyzes the results given the current state of concussion biomechanics. METHODS: Consistency checks were applied to the sensor data collected in the head of each test dummy. Inconsistent data were corrected using analytical techniques, and head kinematics were recalculated from the corrected data. Reconstruction videos were reviewed to identify artefactual impacts during the reconstruction to establish the region of applicability for simulations. Corrected head kinematics were input into finite element brain models to investigate strain response to the corrected dataset. FINDINGS: Multiple reconstruction cases had inconsistent sensor arrays caused by a problematic sensor; corrections to the arrays caused changes in calculated rotational head motion. These corrections increased median peak angular velocity for the concussion cases from 35.6 to 41.5â¯rad/s. Using the original kinematics resulted in an average error of 20% in maximum principal strain results for each case. Simulations of the reconstructions also demonstrated that simulation lengths less than 40â¯ms did not capture the entire brain strain response and under-predicted strain. INTERPRETATION: This study corrects data that were used to determine concussion risk, and indicates altered head angular motion and brain strain response for many reconstructions. Conclusions based on the original data should be re-examined based on this new study.
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Traumatismos en Atletas/fisiopatología , Conmoción Encefálica/fisiopatología , Fútbol Americano , Dispositivos de Protección de la Cabeza , Aceleración , Algoritmos , Fenómenos Biomecánicos , Encéfalo/fisiopatología , Simulación por Computador , Diseño de Equipo , Análisis de Elementos Finitos , Cabeza , Humanos , MasculinoRESUMEN
BACKGROUND: Concussions in American football remain a high priority of sports injury prevention programs. Detailed video review provides important information on causation, the outcomes of rule changes, and guidance on future injury prevention strategies. PURPOSE: Documentation of concussions sustained in National Football League games played during the 2015-2016 and 2016-2017 seasons, including consideration of video views unavailable to the public. STUDY DESIGN: Descriptive epidemiology study. METHODS: All reported concussions were reviewed with all available video footage. Standardized terminology and associated definitions were developed to describe and categorize the details of each concussion. RESULTS: Cornerbacks sustained the most concussions, followed by wide receivers, then linebackers and offensive linemen. Half (50%) of concussions occurred during a passing play, 28% during a rushing play, and 21% on a punt or kickoff. Tackling was found to be the most common activity of concussed players, with the side of the helmet the most common helmet impact location. The distribution of helmet impact source-the object that contacted the concussed player's helmet-differed from studies of earlier seasons, with a higher proportion of helmet-to-body impacts (particularly shoulder) and helmet-to-ground impacts and with a lower proportion of helmet-to-helmet impacts. Helmet-to-ground concussive impacts were notable for the high prevalence of impacts to the back of the helmet and their frequency during passing plays. CONCLUSION: Concussion causation scenarios in the National Football League have changed over time. CLINICAL RELEVANCE: The results of this study suggest the need for expanded evaluation of concussion countermeasures beyond solely helmet-to-helmet test systems, including consideration of impacts with the ground and with the body of the opposing player. It also suggests the possibility of position-specific countermeasures as part of an ongoing effort to improve safety.
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Conmoción Encefálica/epidemiología , Fútbol Americano/lesiones , Traumatismos en Atletas/epidemiología , Traumatismos en Atletas/fisiopatología , Fenómenos Biomecánicos/fisiología , Conmoción Encefálica/fisiopatología , Conmoción Encefálica/prevención & control , Dispositivos de Protección de la Cabeza , Humanos , Masculino , Prevalencia , Estaciones del Año , Estados Unidos/epidemiología , Grabación en VideoRESUMEN
Compression of the leg induces bending in the tibia, which can lead to tensile failure of the bone in the midshaft. The purpose of this study was to determine the orientation of the compressive load vector in the human tibia. Five cadaveric lower extremities were instrumented with in situ 6-axis tibial and fibular load cells and subjected to quasistatic axial leg compression tests in two knee positions and nine ankle positions. For each test, the location and angle of the line of action were calculated at the tibial midshaft. The line of action was extended to the bone ends in order to determine the locations of the effective centers of pressure on the tibial plafond and tibial plateau. The effective center of pressure on the tibial plafond consistently migrated anteriorly in dorsiflexion, laterally in eversion, posteriorly in plantarflexion, and medially in inversion. An opposite pattern was observed on the tibial plateau. When the knee was flexed, the effective center of pressure was generally isolated to a small area in the posterior portion of the medial tibial condyle. The percentage of the axial load borne by the fibula varied from -8% to 19%, and was related to the inversion/eversion angle of the ankle (p<0.02), as well as the distance between the fibula and the axial load path at the midshaft (p<0.001). The line of action through the tibia appeared to follow the external load path to the extent allowed by the available joint contact surfaces.
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Rodilla/fisiología , Tibia/fisiología , Anciano , Anciano de 80 o más Años , Fuerza Compresiva , Femenino , Humanos , Rodilla/anatomía & histología , Masculino , Persona de Mediana Edad , Estrés Mecánico , Tibia/anatomía & histología , Soporte de Peso/fisiologíaRESUMEN
BACKGROUND: Fracture of the lateral process of the talus is an unusual injury that has received heightened attention in recent years because of its association with snowboarding. The diagnosis is often confused with that of lateral ankle sprain. If left untreated, it can cause long-term impairment, including osteoarthritis and subtalar joint degeneration. It is generally thought to result from dorsiflexion and inversion. However, few experimental studies have been conducted to investigate the injury mechanism. HYPOTHESIS: Eversion of a dorsiflexed ankle is more likely to fracture the lateral process of the talus than inversion of a dorsiflexed ankle. STUDY DESIGN: Controlled laboratory study. METHODS: Ten cadaveric leg specimens were subjected to dynamic inversion or eversion of an axially loaded and dorsiflexed ankle. RESULTS: Inversion failed to produce any fractures in three injured specimens. However, all six specimens subjected to eversion sustained a fracture of the lateral process of the talus. CONCLUSIONS: The incidence of fracture of the lateral process of the talus was significantly higher in the eversion group compared with the inversion group. CLINICAL RELEVANCE: Eversion of an axially loaded and dorsiflexed ankle may be an important injury mechanism for fracture of the lateral process of the talus among snowboarders.
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Fracturas Óseas/etiología , Fracturas Óseas/fisiopatología , Esquí/lesiones , Astrágalo/lesiones , Anciano , Cadáver , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Rotación , Estrés MecánicoRESUMEN
The tibia index (TI) is commonly used to predict leg injury based on measurements taken by an anthropomorphic test device (ATD). The TI consists of an interaction formula that combines axial loading and bending plus a supplemental compressive force criterion. Current ATD lower limbs lack geometric biofidelity with regard to tibial curvature and fibular load-sharing. Due to differences in tibial curvature, the midshaft moments induced by axial loading are different in humans and ATDs. Midshaft tibial loading in the human is also reduced by load-sharing through the fibula, which is not replicated in current ATDs. In this study, tibial curvature and fibular load-sharing are quantified through CT imaging and biomechanical testing, and equations are presented to correct ATD measurements to reflect the loading that would be experienced by a human tibia.
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Peroné/anatomía & histología , Peroné/fisiología , Tibia/anatomía & histología , Tibia/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Algoritmos , Fuerza Compresiva , Femenino , Peroné/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Radiografía , Tibia/diagnóstico por imagen , Soporte de PesoRESUMEN
Non-collinear low velocity rear end (LVRE) collision human kinematics have not previously been studied. Occupant head and neck motions during twenty similar non-collinear (15 and 30 degree angle) left rear end collisions were analyzed for five male test subjects alternately positioned in the left and right front seats of the struck vehicle. Displacement-time and acceleration data for occupant, seat, and vehicles were determined by 3D motion analyses and linear accelerometer outputs. The dynamics of the struck vehicle at 6.0 to 9.3 kph (3.8 to 5.8 mph) delta-V showed an initial period of yaw, even when the rear tires did not lose traction with the pavement. The brief yaw seen during the 15 degree impacts was accompanied by early relative rightward movement of the vehicle's seat and seatback behind the stationary test subject: the subjects subsequently engaged the left region of the seatback and head restraint. A more pronounced yaw accompanied the loss of rear tire traction during the 30 degree tests, and resulted in occupant contact/loading further toward the left edge of the seat back and head restraint. For a given striking vehicle velocity, the impact severity in terms of head acceleration and changes in head velocity were significantly lower (p<0.05) at vehicle impact angles of 30 degrees compared with 15 degrees. Clinically, there were only minor short-term symptoms and no long-term symptoms observed in these angled impacts.
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Aceleración/efectos adversos , Accidentes de Tránsito , Traumatismos Craneocerebrales/fisiopatología , Movimientos de la Cabeza/fisiología , Traumatismos del Cuello/fisiopatología , Fenómenos Biomecánicos , Estatura/fisiología , Peso Corporal/fisiología , Vértebras Cervicales/fisiopatología , Traumatismos Craneocerebrales/etiología , Humanos , Masculino , Persona de Mediana Edad , Traumatismos del Cuello/etiología , Rango del Movimiento Articular/fisiologíaRESUMEN
Previous epidemiological studies of rollover crashes have focused primarily on serious and fatal injuries in general, while rollover crash testing has focused almost exclusively on cervical spine injury. The purpose of this study was to examine and compare the risk factors for cervical spine, head, serious, and fatal injury in real world rollover crashes. Rollover crashes from 1995-2008 in the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) were investigated. A large data set of 6015 raw cases (2.5 million weighted) was generated. Nonparametric univariate analyses, univariate logistic regression, and multivariate logistic regression were conducted. Complete or partial ejection, a lack of seatbelt use, a greater number of roof inversions, and older occupant age significantly increased the risk of all types of injuries studied (p<0.05). Far side seating position increased the risk of fatal, head, and cervical spine injury (p<0.05), but not serious injury in general. Higher BMI was associated with an increased risk of fatal, serious, and cervical spine injury (p<0.05), but not head injury. Greater roof crush was associated with a higher rate of fatal and cervical spine injury (p<0.05). Vehicle type, occupant height, and occupant gender had inconsistent and generally non-significant effects on injury. This study demonstrates both common and unique risk factors for different types of injuries in rollover crashes.