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Concept: Helmet


Insufficient sleep is common among high school students and has been associated with an increased risk for motor vehicle crashes (1), sports injuries (2), and occupational injuries (3). To evaluate the association between self-reported sleep duration on an average school night and several injury-related risk behaviors (infrequent bicycle helmet use, infrequent seatbelt use, riding with a driver who had been drinking, drinking and driving, and texting while driving) among U.S. high school students, CDC analyzed data from 50,370 high school students (grades 9-12) who participated in the national Youth Risk Behavior Surveys (YRBSs) in 2007, 2009, 2011, or 2013. The likelihood of each of the five risk behaviors was significantly higher for students who reported sleeping ≤7 hours on an average school night; infrequent seatbelt use, riding with a drinking driver, and drinking and driving were also more likely for students who reported sleeping ≥10 hours compared with 9 hours on an average school night. Although insufficient sleep directly contributes to injury risk, some of the increased risk associated with insufficient sleep might be caused by engaging in injury-related risk behaviors. Intervention efforts aimed at these behaviors might help reduce injuries resulting from sleepiness, as well as provide opportunities for increasing awareness of the importance of sleep.

Concepts: Sleep, Injuries, High school, Somnolence, Driver's license, Automobile, Helmet, Remove Intoxicated Drivers


Cycle use across London and the UK has increased considerably over the last 10 years. With this there has been an increased interest in cycle safety and injury prevention. Head injuries are an important cause of mortality and morbidity in cyclists. This study aimed to ascertain the frequency of different head injury types in cyclists and whether wearing a bicycle helmet affords protection against specific types of head injury.

Concepts: Injuries, Cycling, Physical trauma, Accident, Concussion, Helmet, Bicycle helmet


OBJECTIVE Motorcycle helmets have been shown to decrease the incidence and severity of traumatic brain injury due to motorcycle crashes. Despite this proven efficacy, some previous reports and speculation suggest that helmet use is associated with a higher likelihood of cervical spine injury (CSI). In this study, the authors examine 1061 cases of motorcycle crash victims who were treated during a 5-year period at a Level 1 trauma center to investigate the association of helmet use with the incidence and severity of CSI. The authors hypothesized that wearing a motorcycle helmet during a motorcycle crash is not associated with an increased risk of CSI and may provide some protective advantage to the wearer. METHODS The authors performed a retrospective review of all cases in which the patient had been involved in a motorcycle crash and was evaluated at a single Level 1 trauma center in Wisconsin between January 1, 2010, and January 1, 2015. Biometric, clinical, and imaging data were obtained from a trauma registry database. The patients were then divided into 2 distinct groups based on whether or not they were wearing helmets at the time of the accident. Baseline and functional characteristics were compared between the 2 groups. The Student t-test was used for continuous variables, and Pearson’s chi-square analysis was used for categorical variables. RESULTS In total, 1061 patient charts were examined containing data on 738 unhelmeted (69.6%) and 323 helmeted (30.4%) motorcycle riders. On average, helmeted riders had a much lower Injury Severity Score (p < 0.001). Cervical spine injury occurred in 114 unhelmeted riders (15.4%) compared with only 24 helmeted riders (7.4%) (p < 0.001), with an adjusted odds ratio of 2.3 (95% CI 1.44-3.61, p = 0.0005). In the unhelmeted group, 10.8% of patients were found to have a cervical spine fracture compared with only 4.6% of patients in the helmeted group (p = 0.001). Additionally, ligamentous injury occurred more frequently in unhelmeted riders (1.9% vs 0.3%, p = 0.04). No difference was found in the occurrence of cervical strain, cord contusion, or nerve root injury (all p > 0.05). CONCLUSIONS The results of this study demonstrate a statistically significant lower likelihood of suffering a CSI among helmeted motorcyclists. Unhelmeted riders sustained a statistically significant higher number of vertebral fractures and ligamentous injuries. The study findings reported here confirm the authors' hypothesis that helmet use does not increase the risk of developing a cervical spine fracture and may provide some protective advantage.

Concepts: Traumatic brain injury, Vertebral column, Physical trauma, Motorcycle, Motorcycle helmet, Helmet, Bicycle helmet, Helmets


It has been suggested that the safety benefits of bicycle helmets are limited by risk compensation. The current article tests if previous helmet use influences the response to helmets as a safety intervention. This was investigated in a field experiment where pace and psychophysiological load were measured. We found that after having removed their helmets, routine helmet users cycled more slowly and demonstrated increased psychophysiological load. However, for non-users there was no significant change in either cycling behaviour or psychophysiological load. We discuss the implications of these results for a hypothesis of risk compensation in response to helmet use. We also show that heart rate variability is a promising measure of psychophysiological load in real-world cycling, at least in situations where there is limited physical demand.

Concepts: Experiment, Cycling, Bicycle, Motorcycle helmet, Helmet, Bicycle helmet, Helmets, Utility cycling


Object Bicycle accidents are a very important cause of clinically important traumatic brain injury (TBI) in children. One factor that has been shown to mitigate the severity of lesions associated with TBI in such scenarios is the proper use of a helmet. The object of this study was to test and evaluate the protection afforded by a children’s bicycle helmet to human cadaver skulls with a child’s anthropometry in both “impact” and “crushing” situations. Methods The authors tested human skulls with and without bicycle helmets in drop tests in a monorail-guided free-fall impact apparatus from heights of 6 to 48 in onto a flat steel anvil. Unhelmeted skulls were dropped at 6 in, with progressive height increases until failure (fracture). The maximum resultant acceleration rates experienced by helmeted and unhelmeted skulls on impact were recorded by an accelerometer attached to the skulls. In addition, compressive forces were applied to both helmeted and unhelmeted skulls in progressive amounts. The tolerance in each circumstance was recorded and compared between the two groups. Results Helmets conferred up to an 87% reduction in so-called mean maximum resultant acceleration over unhelmeted skulls. In compression testing, helmeted skulls were unable to be crushed in the compression fixture up to 470 pound-force (approximately 230 kgf), whereas both skull and helmet alone failed in testing. Conclusions Children’s bicycle helmets provide measurable protection in terms of attenuating the acceleration experienced by a skull on the introduction of an impact force. Moreover, such helmets have the durability to mitigate the effects of a more rare but catastrophic direct compressive force. Therefore, the use of bicycle helmets is an important preventive tool to reduce the incidence of severe associated TBI in children as well as to minimize the morbidity of its neurological consequences.

Concepts: Brain, Traumatic brain injury, Compressive stress, Bicycle, Motorcycle helmet, Helmet, Bicycle helmet, Helmets


With the recent worldwide increase in ski helmet use, new market trends are developing, including audio helmets for listening to music while skiing or snowboarding. The aim of this study was to evaluate whether listening to music with an audio ski helmet impairs reaction time to peripheral stimuli. A within-subjects design study using the Compensatory-Tracking-Test was performed on 65 subjects (36 males and 29 females) who had a mean age of 23.3±3.9 years. Using repeated measures analysis of variance, we found significant differences in reaction times between the 4 test conditions (p=0.039). The lowest mean reaction time (±SE) was measured for helmet use while listening to music (507.9±13.2 ms), which was not different from helmet use alone (514.6±12.5 ms) (p=0.528). However, compared to helmet use while listening to music, reaction time was significantly longer for helmet and ski goggles used together (535.8±14.2 ms, p=0.005), with a similar trend for helmet and ski goggles used together while listening to music (526.9±13.8 ms) (p=0.094). In conclusion, listening to music with an audio ski helmet did not increase mean reaction time to peripheral stimuli in a laboratory setting.

Concepts: Analysis of variance, Skiing, Reaction time, Helmet, Helmets, Snowboarding, Skiing equipment, Sports equipment


ABSTRACT Objectives One of the main requirements of a protective helmet is to provide and maintain appropriate and adequate coverage to the head. A helmet that is poorly fitted or fastened may become displaced during normal use or even ejected during a crash. Methods Observations and measurements of head dimensions, helmet position, adjustment, and stability were made on 216 motorcyclists. Helmet details were recorded. Participants completed a questionnaire on helmet usability and their riding history. Helmet stability was assessed quasi-statically. Results Differences between the dimensions of ISO headforms and equivalent sized motorcyclists' heads were observed, especially head width. Almost all (94%) of the helmets were labelled to be compliant with AS/NZS 1698. The majority of riders were satisfied with the comfort, fit, and usability aspects of their helmets. The majority of helmets were deemed to have been worn correctly. Using quasi-static pull tests, it was found that helmet type (open-face or full-face) and the wearing correctness were among factors that affected the loads at which helmets became displaced. The forces required to displace the helmet were low, around 25 N. Conclusions The size of the in-use motorcycle helmets did not correspond well to the predicted size based on head dimensions, although motorcyclists were generally satisfied with comfort and fit. The in vivo stability tests appear to over predict that helmets will come off in a crash, based on the measured forces, tangential forces measured in the oblique impact tests, and the actual rate of helmet ejection.

Concepts: Scientific method, Observation, Motorcycle, Motorcycle helmet, Helmet, Bicycle helmet, Helmets, Motorcycle safety


Modern ballistic helmets defeat penetrating bullets by energy transfer from the projectile to the helmet, producing helmet deformation. This deformation may cause severe injuries without completely perforating the helmet, termed “behind armor blunt trauma” (BABT). As helmets become lighter, the likelihood of larger helmet backface deformation under ballistic impact increases. To characterize the potential for BABT, seven postmortem human head/neck specimens wearing a ballistic protective helmet were exposed to nonperforating impact, using a 9 mm, full metal jacket, 124 grain bullet with velocities of 400-460 m/s. An increasing trend of injury severity was observed, ranging from simple linear fractures to combinations of linear and depressed fractures. Overall, the ability to identify skull fractures resulting from BABT can be used in forensic investigations. Our results demonstrate a high risk of skull fracture due to BABT and necessitate the prevention of BABT as a design factor in future generations of protective gear.

Concepts: Bone fracture, Concussion, Bullet, Ammunition, Helmet, Skull fracture, Full metal jacket bullet, Full Metal Jacket


There is a paucity of published systematic research investigating object detection within the military context. Here, we establish baseline human detection performance for five standard military issued camouflage patterns. Stimuli were drawn from a database of 1242 calibrated images of a mixed deciduous woodland environment in Bristol, UK. Images within this database were taken during daylight hours, in summer and contained a PASGT helmet, systematically positioned within each scene. Subjects (20) discriminated between the two image types in a temporal 2AFC task (500ms presentation for each interval), with the detection scenario being the percentage of instances participants correctly detected the target. Cueing (cued/not-cued to target location), colour (colour/greyscale) and distance from the observer (3.5/5/7.5m) were manipulated, as was helmet camouflage pattern. A Generalized Linear Mixed Model revealed significant interactions between all variables on participant performance, with greater accuracy when stimuli were in colour, and the target location was cued. There was also a clear ranking of patterns in terms of effectiveness of camouflage. We also compare the results with a computational model based on low-level vision, and eye tracking data, with encouraging results. Our methodology provides a controlled means of assessing any camouflage in any environment, and the potential to implement a machine vision solution to assessment. In this instance, we show differences in the effectiveness of existing solutions to the problem of camouflage, concealment and deception (CCD) on the battlefield. Funded by QinetiQ as part of Materials and Structures Low Observable Materials Research Programme. Meeting abstract presented at VSS 2015.

Concepts: Deception, Camouflage, Helmet, Military camouflage, Personnel Armor System for Ground Troops, ERDL pattern, Army Combat Uniform


Soldiers in military vehicles subjected to underbelly blasts can sustain traumatic head and neck injuries due to a head impact with the roof. The severity of head and neck trauma can be influenced by the amount of head clearance available to the occupant, but also by other factors such as wearing a military helmet or the presence of padding on the interior roof. The aim of the current study was to examine the interaction between a Hybrid III headform, the helmet system and the interior roof of the vehicle under vertical loading.

Concepts: Head and neck anatomy, Head and neck, Injuries, Physical trauma, Concussion, British Columbia, British Columbia Interior, Helmet