Comparison of Ice Hockey Goaltender Helmets for Concussion Type Impacts

Concussions are among the most common injuries sustained by ice hockey goaltenders and can result from collisions, falls and puck impacts. However, ice hockey goaltender helmet certification standards solely involve drop tests to a rigid surface. This study examined how the design characteristics of different ice hockey goaltender helmets affect head kinematics and brain strain for the three most common impact events associated with concussion for goaltenders. A NOCSAE headform was impacted under conditions representing falls, puck impacts and shoulder collisions while wearing three different types of ice hockey goaltender helmet models. Resulting linear and rotational acceleration as well as maximum principal strain were measured for each impact condition. The results indicate that a thick liner and stiff shell material are desirable design characteristics for falls and puck impacts to reduce head kinematic and brain tissue responses. However for collisions, the shoulder being more compliant than the materials of the helmet causes insufficient compression of the helmet materials and minimizing any potential performance differences. This suggests that current ice hockey goaltender helmets can be optimized for protection against falls and puck impacts. However, given collisions are the leading cause of concussion for ice hockey goaltenders and the tested helmets provided little to no protection, a clear opportunity exists to design new goaltender helmets which can better protect ice hockey goaltenders from collisions.     

Development of the STAR Evaluation System for Football Helmets: Integrating Player Head Impact Exposure and Risk of Concussion

In contrast to the publicly available data on the safety of automobiles, consumers have no analytical mechanism to evaluate the protective performance of football helmets. The objective of this article is to fill this void by introducing a new equation that can be used to evaluate helmet performance by integrating player head impact exposure and risk of concussion. The Summation of Tests for the Analysis of Risk (STAR) equation relates on-field impact exposure to a series of 24 drop tests performed at four impact locations and six impact energy levels. Using 62,974 head acceleration data points collected from football players, the number of impacts experienced for one full season was translated to 24 drop test configurations. A new injury risk function was developed from 32 measured concussions and associated exposure data to assess risk of concussion for each impact. Finally, the data from all 24 drop tests is combined into one number using the STAR formula that incorporates the predicted exposure and injury risk for one player for one full season of practices and games. The new STAR evaluation equation will provide consumers with a meaningful metric to assess the relative performance of football helmets.     

Frequency and location of head impact exposures in individual collegiate football players

Context:

Measuring head impact exposure is a critical step toward understanding the mechanism and prevention of sport-related mild traumatic brain (concussion) injury, as well as the possible effects of repeated subconcussive impacts.

Objective:

To quantify the frequency and location of head impacts that individual players received in 1 season among 3 collegiate teams, between practice and game sessions, and among player positions.

Design:

Cohort study.

Setting:

Collegiate football field.

Patients or Other Participants:

One hundred eighty-eight players from 3 National Collegiate Athletic Association football teams.

Intervention(s):

Participants wore football helmets instrumented with an accelerometer-based system during the 2007 fall season.

Main Outcome Measure(s):

The number of head impacts greater than 10g and location of the impacts on the player''s helmet were recorded and analyzed for trends and interactions among teams (A, B, or C), session types, and player positions using Kaplan-Meier survival curves.

Results:

The total number of impacts players received was nonnormally distributed and varied by team, session type, and player position. The maximum number of head impacts for a single player on each team was 1022 (team A), 1412 (team B), and 1444 (team C). The median number of head impacts on each team was 4.8 (team A), 7.5 (team B), and 6.6 (team C) impacts per practice and 12.1 (team A), 14.6 (team B), and 16.3 (team C) impacts per game. Linemen and linebackers had the largest number of impacts per practice and per game. Offensive linemen had a higher percentage of impacts to the front than to the back of the helmet, whereas quarterbacks had a higher percentage to the back than to the front of the helmet.

Conclusions:

The frequency of head impacts and the location on the helmet where the impacts occur are functions of player position and session type. These data provide a basis for quantifying specific head impact exposure for studies related to understanding the biomechanics and clinical aspects of concussion injury, as well as the possible effects of repeated subconcussive impacts in football.     

Impact Performance of Modern Football Helmets

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.     

Change in Size and Impact Performance of Football Helmets from the 1970s to 2010

Linear impactor tests were conducted on football helmets from the 1970s–1980s to complement recently reported tests on 1990s and 2010s helmets. Helmets were placed on the Hybrid III head with an array of accelerometers to determine translational and rotational acceleration. Impacts were at four sites on the helmet shell at 3.6–11.2 m/s. The four generations of helmets show a continuous improvement in response from bare head impacts in terms of Head Injury Criterion (HIC), peak head acceleration and peak rotational acceleration. Helmets of 2010s weigh 1.95 ± 0.2 kg and are 2.7 times heavier than 1970s designs. They are also 4.3 cm longer, 7.6 cm higher, and 4.9 cm wider. The extra size and weight allow the use of energy absorbing padding that lowers forces in helmet impacts. For frontal impacts at 7.4 m/s, the four best performing 2010s helmets have HIC of 148 ± 23 compared to 179 ± 42 for the 1990s baseline, 231 ± 27 for the 1980s, 253 ± 22 for the 1970s helmets, and 354 ± 3 for the bare head. The additional size and padding of the best 2010s helmets provide superior attenuation of impact forces in normal play and in conditions associated with concussion than helmets of the 1970s–1990s.     

Head Impact Exposure in Youth Football: High School Ages 14 to 18 Years and Cumulative Impact Analysis

Sports-related concussion is the most common athletic head injury with football having the highest rate among high school athletes. Traditionally, research on the biomechanics of football-related head impact has been focused at the collegiate level. Less research has been performed at the high school level, despite the incidence of concussion among high school football players. The objective of this study is to twofold: to quantify the head impact exposure in high school football, and to develop a cumulative impact analysis method. Head impact exposure was measured by instrumenting the helmets of 40 high school football players with helmet mounted accelerometer arrays to measure linear and rotational acceleration. A total of 16,502 head impacts were collected over the course of the season. Biomechanical data were analyzed by team and by player. The median impact for each player ranged from 15.2 to 27.0 g with an average value of 21.7 (±2.4) g. The 95th percentile impact for each player ranged from 38.8 to 72.9 g with an average value of 56.4 (±10.5) g. Next, an impact exposure metric utilizing concussion injury risk curves was created to quantify cumulative exposure for each participating player over the course of the season. Impacts were weighted according to the associated risk due to linear acceleration and rotational acceleration alone, as well as the combined probability (CP) of injury associated with both. These risks were summed over the course of a season to generate risk weighted cumulative exposure. The impact frequency was found to be greater during games compared to practices with an average number of impacts per session of 15.5 and 9.4, respectively. However, the median cumulative risk weighted exposure based on combined probability was found to be greater for practices vs. games. These data will provide a metric that may be used to better understand the cumulative effects of repetitive head impacts, injury mechanisms, and head impact exposure of athletes in football.     

Removal time and efficacy of riddell quick release face guard attachment system side clips during 1 football season

Context

In the National Athletic Trainers'' Association position statement, “Acute Management of the Cervical Spine-Injured Athlete,” the technique recommended for face-mask (FM) removal is one that “creates the least head and neck motion, is performed most quickly, is the least difficult, and carries the least chance of failure.” Industrial and technological advances in football helmet design and FM attachment systems might influence the efficacy of emergency FM removal.

Objective

To examine the removal times and success rates of the Quick Release (QR) Face Guard Attachment System (Riddell Sports, Inc, Elyria, OH) throughout and at the conclusion of 1 season of play by a National Collegiate Athletic Association Division III football team competing in the Midwest.

Design

Controlled laboratory study.

Setting

College laboratory.

Patients or Other Participants

A total of 69 randomly selected Revolution IQ (Riddell Sports, Inc) football helmets fitted with the QR system were used.

Intervention(s)

Each helmet was secured to a spine board, and investigators attempted to remove both of the QR side clips from the helmet with the Riddell insertion tool.

Main Outcome Measure(s)

Dependent variables included total time for removal of both QR side clips from the FM and success rate for removal of both side clips.

Results

The overall success rate for removal of both clips was 94.8% (164/173), whereas the mean times for removal of both clips ranged from 9.92 ± 12.06 seconds to 16.65 ± 20.97 seconds over 4 trial sessions. We found no differences among mean times for trial sessions throughout the season of play among the same helmets or among different helmets (P > .05).

Conclusions

Removal time and success rate of the Riddell QR were satisfactory during and after 1 season of play despite use in various temperatures and precipitation.Key Words: protective equipment, football injuries, cervical spine, airway management, emergency management

Key Points

• The success rate for removing the individual side clips of helmets fitted with the Riddell Quick Release (QR) Face Guard Attachment System and worn during 1 season of play was 97.4%.
• Times were not different for removing the QR side clips among the same helmets tested throughout the season or for removing the side clips between helmets initially tested at different times in the season.
• The QR system facilitated a satisfactory method of face-mask removal; however, athletic trainers should have the proper backup tool available to remove the face mask, and they should use the pocket-mask insertion method or remove the helmet and shoulder pads to gain access quickly to the airway if the side clips cannot be removed.

Management of a suspected cervical spine injury in a football player is one of the most critical situations that a certified athletic trainer can encounter. This type of injury can involve respiratory compromise, requiring quick airway access through removing the face mask (FM) from the football helmet. Minimizing head and neck movement during FM removal also is imperative because excessive movement can increase the severity of spinal injuries.^1–4The current standard of practice in managing a football athlete with a possible spinal cord injury was established in the National Athletic Trainers'' Association (NATA) position statement, “Acute Management of the Cervical Spine-Injured Athlete.”⁵ The Inter-Association Task Force for Appropriate Care of the Spine-Injured Athlete⁶ previously provided guidelines for the management of such injuries. In the NATA⁵ position statement, the technique recommended for removing a FM “creates the least head and neck motion, is performed most quickly, is the least difficult, and carries the least chance of failure.” The Inter-Association Task Force for Appropriate Care of the Spine-Injured Athlete⁶ recommended leaving the football player''s helmet in place but removing the FM from the helmet “as quickly as possible and with as little movement of the head and neck as possible.” Researchers have determined that the combined-tool approach of the cordless screwdriver as the primary removal tool and a cutting tool as the secondary tool provides a fast, reliable means of on-field FM removal.^7–9Recent technological developments in football helmet design have led to changes in traditional football helmets, including the FM attachment system. Specifically, the recent modifications in the Revolution IQ (Riddell Sports, Inc, Elyria, OH) football helmet include a quick-release FM attachment system. The Riddell Quick Release (QR) Face Guard Attachment System (Riddell Sports, Inc) is used to attach the 2 side clips, whereas the top 2 loop straps are attached with the traditional screw and T-nut design. Researchers studying the QR side clips have shown the average time to remove the FM is faster and the resultant head motion are less than those with a traditional FM attachment system.^10,11Research on the QR system is limited and mostly has been conducted on new football equipment. To our knowledge, authors of only 1 other study¹² have investigated QR side clips on equipment that has been used during football participation. A season of play might affect football equipment due to factors associated with weather, multiple impacts, and playing surfaces. These conditions also might cause difficulties with removal of the FM with the QR side clips. Therefore, the purpose of our study was to examine the removal times and success rates of the QR system during and at the conclusion of 1 season of play by a midwestern collegiate football team participating at the National Collegiate Athletic Association Division III level. We developed 2 research hypotheses to guide the statistical approach: (1) frequency of QR side-clip removal failures and the mean times to complete QR side-clip removal would increase as the season progressed, and (2) frequency of QR side-clip removal failures and the mean times to complete QR side-clip removal would be greater at the end of the season than at preseason.     

Football face-mask removal with a cordless screwdriver on helmets used for at least one season of play

Context: The Inter-Association Task Force for the Appropriate Care of the Spine-Injured Athlete recommends leaving a football player''s helmet in place and removing the face mask from the helmet “as quickly as possible and with as little movement of the head and neck as possible.” Although 2 groups have studied face-mask removal from new equipment, to our knowledge no researchers have investigated equipment that has been previously used. A full season of play may have a significant effect on football equipment and its associated hardware. Countless impacts, weather, playing surfaces, sweat, and other unforeseen or unknown variables might make the face-mask removal process more difficult on equipment that has been used.Objective: To determine the percentage of face masks that we could unscrew, with a cordless screwdriver, from football helmets used for a full season.Design: Cross-sectional.Setting: Three New England high schools.Patients or Other Participants: All football helmets used at 3 local high schools were tested (n = 222, mean games, 9.7 ± 1.2; mean practice weeks, 13.7 ± 1.2).Intervention(s): Each helmet was secured to a board, and a cordless screwdriver was used to attempt to remove all 4 screws attaching the face mask to the helmet.Main Outcome Measure(s): Variables included overall success or failure, time required for face-mask removal, and success by screw location. Data were analyzed with χ², analysis of variance, and Tamhane post hoc tests.Results: Overall, 832 (94%) of 885 screws were unscrewed, and 183 (82.4%) of 222 face masks were removed. Mean removal time was 26.9 ± 5.83 seconds. Face-mask removal success was significantly different between school 1 (24 [52.2%] of 46) and schools 2 (84 [91.3%] of 92) and 3 (75 [89.3%] of 84; F_2,219 = 24.608; P < .001). The removal success rate was significantly higher at top screws (98%) than at screws adjacent to ear holes (90%) (P < .001).Conclusions: Based on our results and previous findings that demonstrated quicker access time and reduced head movement associated with the use of the screwdriver compared with cutting tools, the former may be a good tool for face-mask removal. However, an appropriate cutting tool must be immediately available should the screwdriver fail. Helmet hardware adjacent to ear holes was more vulnerable to failure, perhaps because it is protected by less padding than the top hardware. Possible causes of the higher failure rate at school 1 are the use of hardware materials subject to rust and corrosion and differences in helmet brand; these areas warrant future research and rules consideration.     

气囊式头盔防护下的两轮车骑车人头部损伤风险分析

目的 提出一种气囊式头盔缓冲内衬结构,并分析其对两轮车骑车人头部损伤的防护效果。方法 将气囊式内衬应用于自行车（半盔）和摩托车（全盔）两款典型的两轮车骑车人头盔,通过标准GB 24429-2009和法规ECE R22.05测试工况下的有限元碰撞仿真,获得人体头部模型运动学和生物力学响应,从颅骨骨折和颅脑损伤风险角度对比常规聚苯乙烯泡沫塑料（expanded polystyrene, EPS）头盔,综合评价气囊式头盔的防护性能。结果 当气囊压力为0.06 MPa时,气囊式头盔（半盔/全盔）防护下的人体头部颅骨骨折相关量分别小于120 g和150 g,颅骨骨折风险基本低于40%;颅脑最大主应变均小于0.3,轻度脑损伤风险均低于25%;气囊式头盔防护下的人体颅骨骨折和颅脑损伤风险均低于EPS头盔。结论 本文设计的气囊式头盔具有较好的防护效果,能兼顾颅骨骨折和颅脑损伤防护,可以为新型头盔的设计提供基础示例。损伤风险分析也可为骑车人头部损伤应急诊断提供初步参考。     

A national survey about parent awareness of the risk of severe brain injury from playing football

A survey was conducted to determine the level of awareness among parents of high school football players about the risk of severe brain injury. A national sample of 1007 randomly selected households was interviewed by telephone during February, 1992. All interviewees were parents of high school football players who either were currently playing football or had played within the previous 5 years. Survey questions measured the extent to which parents were aware both of the risks associated with playing high school football and the existing helmet warnings about those risks. Overall, the survey results demonstrated that parents of high school football players were uninformed about both the risk of severe brain injury from playing high school football and the football helmet warnings about that risk. Specifically, unprompted, most parents mentioned broken bones, knee injuries, sprains, or shoulder injuries as hazards associated with playing football. Few parents mentioned severe brain damage, even when prompted. Further, the overwhelming majority of parents incorrectly believed that wearing a football helmet generally eliminated the risk of severe brain injury. Very few parents had received information from any source about the risks of head injury or had heard that no football helmet can provide complete protection against this hazard. Few parents were aware of the warning label on the helmet or knew what the label said, even when prompted. In short, parents were unaware of the risk of severe brain damage, misinformed about a football helmet's ability to protect against this risk, and uninformed about the football helmet warning label about this risk.     

Head impact exposure in youth football

The head impact exposure for athletes involved in football at the college and high school levels has been well documented; however, the head impact exposure of the youth population involved with football has yet to be investigated, despite its dramatically larger population. The objective of this study was to investigate the head impact exposure in youth football. Impacts were monitored using a custom 12 accelerometer array equipped inside the helmets of seven players aged 7–8 years old during each game and practice for an entire season. A total of 748 impacts were collected from the 7 participating players during the season, with an average of 107 impacts per player. Linear accelerations ranged from 10 to 100 g, and the rotational accelerations ranged from 52 to 7694 rad/s². The majority of the high level impacts occurred during practices, with 29 of the 38 impacts above 40 g occurring in practices. Although less frequent, youth football can produce high head accelerations in the range of concussion causing impacts measured in adults. In order to minimize these most severe head impacts, youth football practices should be modified to eliminate high impact drills that do not replicate the game situations.     

The Relationship Between Subconcussive Impacts and Concussion History on Clinical Measures of Neurologic Function in Collegiate Football Players

Concussions sustained during college and professional football careers have been associated with both acute and chronic neurologic impairment. The contribution of subconcussive impacts to this impairment has not been adequately studied. Therefore, we investigated the relationship between subconcussive impacts and concussion history on clinical measures of neurologic function. Forty-six collegiate football players completed five clinical measures of neurologic function commonly employed in the evaluation of concussion before and after a single season. These tests included the Automated Neuropsychological Assessment Metrics, Sensory Organization Test, Standardized Assessment of Concussion, Balance Error Scoring System, and Graded Symptom Checklist. The Head Impact Telemetry (HIT) System recorded head impact data including the frequency, magnitude, and location of impacts. College football players sustain approximately 1,000 subconcussive impacts to the head over the course of a season, but for the most part, do not demonstrate any clinically meaningful changes from preseason to postseason on measures of neurologic function. Changes in performance were mostly independent of prior concussion history, and the total number, magnitude and location of sustained impacts over one season as observed R ² values ranged between 0.30 and 0.35. Repetitive subconcussive head impacts over a single season do not appear to result in short-term neurologic impairment, but these relationships should be further investigated for a potential dose–response over a player’s career.     

A discussion of the issue of football helmet removal in suspected cervical spine injuries

In some areas, it is a commonly accepted emergency medical technician protocol to remove a helmet during the initial management of suspected cervical spine injures. After a comprehensive survey of relevant literature, four primary reasons why Emergency Medical Services professionals would desire to remove a helmet emerge. Sources suggest that the presence of a helmet might: 1) interfere with immobilization of the athlete; 2) interfere with the ability to visualize injuries; 3) cause hyperflexion of the cervical spine; and 4) prevent proper airway management during a cardiorespiratory emergency. Many available protocols are designed for the removal of closed chamber motorcycle helmets that do not have removable face masks. There are a great number of differing viewpoints regarding this issue. The varying viewpoints are results of the failure of many emergency medical technician management protocols to address the unique situation presented by a football helmet. We: 1) demonstrate that football helmet removal is potentially dangerous and unnecessary, 2) suggest that cardiorespiratory emergencies can be effectively managed without removing the helmet, and 3) provide sports medicine professional with information that may be used to establish a joint Emergency Medical Services/Sports Medicine emergency action plan.     

Nano-Composite Foam Sensor System in Football Helmets

American football has both the highest rate of concussion incidences as well as the highest number of concussions of all contact sports due to both the number of athletes and nature of the sport. Recent research has linked concussions with long term health complications such as chronic traumatic encephalopathy and early onset Alzheimer’s. Understanding the mechanical characteristics of concussive impacts is critical to help protect athletes from these debilitating diseases and is now possible using helmet-based sensor systems. To date, real time on-field measurement of head impacts has been almost exclusively measured by devices that rely on accelerometers or gyroscopes attached to the player’s helmet, or embedded in a mouth guard. These systems monitor motion of the head or helmet, but do not directly measure impact energy. This paper evaluates the accuracy of a novel, multifunctional foam-based sensor that replaces a portion of the helmet foam to measure impact. All modified helmets were tested using a National Operating Committee Standards for Athletic Equipment-style drop tower with a total of 24 drop tests (4 locations with 6 impact energies). The impacts were evaluated using a headform, instrumented with a tri-axial accelerometer, mounted to a Hybrid III neck assembly. The resultant accelerations were evaluated for both the peak acceleration and the severity indices. These data were then compared to the voltage response from multiple Nano Composite Foam sensors located throughout the helmet. The foam sensor system proved to be accurate in measuring both the HIC and Gadd severity index, as well as peak acceleration while also providing additional details that were previously difficult to obtain, such as impact energy.     

Emergent Access to the Airway and Chest in American Football Players

Context:

American football has the highest rate of fatalities and catastrophic injuries of any US sport. The equipment designed to protect athletes from these catastrophic events challenges the ability of medical personnel to obtain neutral spine alignment and immobilization during airway and chest access for emergency life-support delivery.

Objective:

To compare motion, time, and difficulty during removal of American football helmets, face masks, and shoulder pads.

Design:

Quasi-experimental, crossover study.

Setting:

Controlled laboratory.

Patients or Other Participants:

We recruited 40 athletic trainers (21 men, 19 women; age = 33.7 ± 11.2 years, height = 173.1 ± 9.2 cm, mass = 80.7 ± 17.1 kg, experience = 10.6 ± 10.4 years).

Intervention(s):

Paired participants conducted 16 trials in random order for each of 4 helmet, face-mask, and shoulder-pad combinations. An 8-camera, 3-dimensional motion-capture system was used to record head motion in live models wearing properly fitted helmets and shoulder pads.

Main Outcome Measure(s):

Time and perceived difficulty (modified Borg CR-10).

Results:

Helmet removal resulted in greater motion than face-mask removal, respectively, in the sagittal (14.88°, 95% confidence interval [CI] = 13.72°, 16.04° versus 7.04°, 95% CI = 6.20°, 7.88°; F_1,19 = 187.27, P < .001), frontal (7.00°, 95% CI = 6.47°, 7.53° versus 4.73°, 95% CI = 4.20°, 5.27°; F_1,19 = 65.34, P < .001), and transverse (7.00°, 95% CI = 6.49°, 7.50° versus 4.49°, 95% CI = 4.07°, 4.90°; F_1,19 = 68.36, P < .001) planes. Face-mask removal from Riddell 360 helmets took longer (31.22 seconds, 95% CI = 27.52, 34.91 seconds) than from Schutt ION 4D helmets (20.45 seconds, 95% CI = 18.77, 22.12 seconds) or complete ION 4D helmet removal (26.40 seconds, 95% CI = 23.46, 29.35 seconds). Athletic trainers required less time to remove the Riddell Power with RipKord (21.96 seconds, 95% CI = 20.61°, 23.31° seconds) than traditional shoulder pads (29.22 seconds, 95% CI = 27.27, 31.17 seconds; t₁₉ = 9.80, P < .001).

Conclusions:

Protective equipment worn by American football players must eventually be removed for imaging and medical treatment. Our results fill a gap in the evidence to support current recommendations for prehospital emergent management in patients wearing protective football equipment. Helmet face masks and shoulder pads with quick-release designs allow for clinically acceptable removal times without inducing additional motion or difficulty.Key Words: cervical spine injury, sudden cardiac event, protective equipment

Key Points

• Face-mask removal induced less motion than helmet removal when accessing the airway.
• Helmet face masks and shoulder pads with quick-release designs allowed for clinically acceptable removal times without inducing additional motion or difficulty.
• The actual ability to effectively ventilate a patient with a helmet on and face mask removed was not studied and has not been established in the literature.

More than 2 million athletes participate in American football each year.¹ The sport has the highest rate of fatalities and catastrophic injuries of any sport,² with most resulting from neurotraumatic (brain, cervical spine) and sudden cardiovascular events. The ability to initiate immediate basic life support in these scenarios is paramount in preventing avoidable sudden death. However, the equipment designed to protect athletes from catastrophic injury challenges the responders'' ability to obtain neutral spine alignment and immobilization during delivery of emergency life support. An investigation is warranted of equipment-removal techniques that may be implemented by emergency care providers (eg, certified or licensed athletic trainers, paramedics, and emergency department staff) giving life support.Acute medical care of the American football player with a potentially catastrophic injury or illness in the prehospital setting (ie, athletic field) necessitates a careful and coordinated approach to minimize sequelae associated with misdiagnosis and mismanagement.³ The prehospital setting presents unique factors that make delivering appropriate care challenging. For example, given that isolated independent removal of football helmets has been shown to move the cervical spine out of neutral alignment,^4–6 the National Athletic Trainers'' Association⁷ recommended that the helmet and shoulder pads remain in place and airway access be achieved via face-mask removal, except under certain circumstances. However, no researchers have published reports comparing helmet removal and face-mask removal to support this recommendation. These recommendations also differ from protocols used by many providers for suspected spine injuries in patients wearing helmets without shoulder pads (eg, cycling, motorsports), when removal of the helmet is necessary to secure airway access and establish neutral cervical alignment.Recent modifications from 2 football-equipment manufacturers involve helmets with face masks that are attached with a full quick-release system designed to release the face mask without removing screws. Previous systems incorporated quick-release face-mask attachments at 2 of 4 positions and appeared to allow for faster and safer airway access than traditional attachments.^8,9 A manufacturer also has modified a shoulder-pad design to incorporate a quick-release feature. Research validating the safety of these designs will provide evidence to support clinical best practices.Therefore, the purpose of our study was to determine the safest emergency intervention to allow for airway and chest access in the presence of different styles of helmets and shoulder pads. To accomplish these objectives, we were most interested in the interaction between airway-access technique and helmet type and the effect of shoulder-pad designs on head movement, time to task completion, and perceived difficulty of removal. We hypothesized that less head movement, less time to task completion, and less perceived difficulty would exist (1) during face-mask removal than during helmet removal, regardless of helmet type, and (2) during shoulder-pad removal using a quick-release shoulder pad design versus a traditional shoulder-pad design.     

Early Results of a Helmetless-Tackling Intervention to Decrease Head Impacts in Football Players

ObjectiveTo test a helmetless-tackling behavioral intervention for reducing head impacts in National Collegiate Athletic Association Division I football players.DesignRandomized controlled clinical trial.SettingFootball field.Intervention(s)The intervention group participated in a 5-minute tackling drill without their helmets and shoulder pads twice per week in the preseason and once per week through the season. During this time, the control group performed noncontact football skills.ResultsHead impacts/AE decreased for the intervention group compared with the control group by the end of the season (9.99 ± 6.10 versus 13.84 ± 7.27, respectively). The intervention group had 30% fewer impacts/AE than the control group by season''s end (9.99 ± 6.10 versus 14.32 ± 8.45, respectively).ConclusionA helmetless-tackling training intervention reduced head impacts in collegiate football players within 1 season.Key Words: injury prevention, athletic injuries, head and neck injuries

Key Points

• Given proper training, education, and instruction, collegiate football players can safely perform supervised tackling and blocking drills in practice without helmets.
• Helmetless tackling eliminates the false sense of security a football player may feel when wearing a helmet.
• Younger football players and those with less experience may require modifications to the intervention to realize a positive effect. More research is needed on players at these levels before widespread implementation.

Head impacts in football players are directly associated with brain and spine injury, have been proposed to be associated with chronic injuries such as chronic traumatic encephalopathy, and have become a national concern. High school and college football participants can experience more than 1000 head impacts in a single season.^1,2 Youth football players may sustain more than 100 impacts in a season, with linear acceleration greater than 80g reported.³ To mitigate the risk of head-impact injury, researchers, league officials, and administrators have sought to improve helmet technology, reduce the number of allowable contact practices, and alter game rules. Although each of these factors has merit, none directly address the common fundamental cause: impacts to the head. In fact, current efforts directed at improving helmet technology may promote a false sense of security⁴ and perpetuate the use of the head as a point of contact during play.^1,5To directly address these concerns, we initiated a study to investigate the effectiveness of a helmetless-tackling behavioral intervention to reduce head-impact exposure in a National Collegiate Athletic Association Division I football program. We share important findings on our primary variable of interest after the first year of data collection.     

Cervical Spine Motion During Football Equipment-Removal Protocols: A Challenge to the All-or-Nothing Endeavor

Context

The National Athletic Trainers'' Association position statement on acute management of the cervical spine-injured athlete recommended the all-or-nothing endeavor, which involves removing or not removing both helmet and shoulder pads, from equipment-laden American football and ice hockey athletes. However, in supporting research, investigators have not considered alternative protocols.

Objective

To measure cervical spine movement (head relative to sternum) produced when certified athletic trainers (ATs) use the all-or-nothing endeavor and to compare these findings with the movement produced using an alternative pack-and-fill protocol, which involves packing the area under and around the cervical neck and head with rolled towels.

Design

Crossover study.

Setting

Movement analysis laboratory.

Patients or Other Participants

Eight male collegiate football players (age = 21.4 ± 1.4 years; height = 1.87 ± 0.02 m; mass = 103.6 ± 12.5 kg).

Intervention(s)

Four ATs removed equipment under 4 conditions: removal of helmet only followed by placing the head on the ground (H), removal of the helmet only followed by pack-and-fill (HP), removal of the helmet and shoulder pads followed by placing the head on the ground (HS), and removal of the helmet and shoulder pads followed by pack-and-fill (HSP). Motion capture was used to track the movement of the head with respect to the sternum during equipment removal.

Main Outcome Measure(s)

We measured head movement relative to sternum movement (translations and rotations). We used 4 × 4 analyses of variance with repeated measures to compare discrete motion variables (changes in position and total excursions) among protocols and ATs.

Results

Protocol HP resulted in a 0.1 ± 0.6 cm rise in head position compared with a 1.4 ± 0.3 cm drop with protocol HS (P < .001). Protocol HP produced 4.9° less total angular excursion (P < .001) and 2.1 cm less total vertical excursion (P < .001) than protocol HS.

Conclusions

The pack-and-fill protocol was more effective than shoulder pad removal in minimizing cervical spine movement throughout the equipment-removal process. This study provides evidence for including the pack-and-fill protocol in future treatment recommendations when helmet removal is necessary for on-field care.Key Words: National Athletic Trainers'' Association position statement, pack and fill, motion analysis, helmet removal

Key Points

• The pack-and-fill protocol resulted in less overall motion than removal of the helmet and shoulder pads followed by placing the head on the ground, which is currently endorsed by the National Athletic Trainers'' Association.
• Using pack and fill, the athletic trainers could position the head at release in, on average, nearly the identical position as at initiation.
• Removal of the helmet and shoulder pads resulted in a drop in linear and angular head position, placing the cervical spine into increased extension.

American football has the highest number of catastrophic cervical spine injuries of all sports in the United States.¹ Although still of major concern, the incidence of catastrophic cervical spine injuries has declined over the past 35 years, and the rate is now less than 1 per 100 000 exposures.² Much of this decline has been attributed to a 1976 rule change making it illegal to spear, or lower the head to butt or ram an opponent.² Given the force applied at the front and top of a player''s helmet, spearing has long been associated with the axial-load mechanism of injury that results in catastrophic cervical spine injury.³ However, despite a focus on player safety, researchers^4–6 have suggested that the incidence of spearing or other axial head impacts may be as prevalent in American football in the United States today as before the 1976 rule change. Instead, improved prehospital care and on-field management of equipment-laden athletes with potential spine injuries possibly also has led to a reduction in catastrophic cervical spine injuries by reducing the number of cervical spine injuries that result in catastrophic outcomes. This possibility needs to be documented, and research pertaining to prehospital care protocols and management techniques that may affect catastrophic spinal cord injury outcomes in American football needs to continue.Proper prehospital on-field medical care of the athlete with a spine injury, including equipment management, may be critical in limiting secondary cervical spine injury while also allowing access to the airway and chest compressions. The National Athletic Trainers'' Association (NATA) position statement on the acute management of the cervical spine-injured athlete⁷ includes the all-or–nothing technique, which discourages independent removal of the helmet or shoulder pads in American football or ice hockey when an athlete has a potential cervical spine injury. This specific NATA recommendation is based on several studies^8–11 in which the researchers measured vertebral positioning or spinal cord space before and after equipment removal and showed that when the football helmet is removed while the shoulder pads remain in place, cervical alignment can be compromised as the head and neck fall backward into extension.However, a gap exists in the body of evidence used to support this recommendation, as no authors of supporting studies have addressed the use of fillers (eg, rolled towels) to stabilize the head and cervical spine after removing only the helmet and leaving the shoulder pads on the athlete. This technique, termed pack and fill, would fill the void of the missing helmet by placing rolled towels around and beneath the posterior head, cervical spine, and surface of the spine board or ground to prevent the head and cervical spine from moving into extension during performance of critical-care tasks. Although the NATA position statement⁷ mentions this technique as a possibility for an athlete whose helmet is dislodged or shoulder pads are not removed easily, pack and fill could be an alternative clinical practice when removal of the helmet is necessary to provide safe access to the airway (eg, inability to remove the facemask efficiently or a poorly fitted football helmet creating instability of the head and cervical spine within the helmet). Decoster et al¹² recently demonstrated that pack and fill can effectively maintain a neutral sagittal cervical alignment after helmet removal.Another gap in these supporting studies is that they were based on static imaging and, therefore, did not account for the amount of head and neck movement that occurs during the equipment-removal process. In the case of shoulder-pad removal, this could be substantial. Therefore, the purposes of our study were to address these 2 gaps by measuring cervical spine movement (head with respect to sternum) throughout the removal process and to compare this movement among several possible removal protocols. We hypothesized that removal of the helmet combined with the pack-and-fill technique would result in less overall movement than removal of both the helmet and shoulder pads.     

Rotational Head Kinematics in Football Impacts: An Injury Risk Function for Concussion

Recent research has suggested a possible link between sports-related concussions and neurodegenerative processes, highlighting the importance of developing methods to accurately quantify head impact tolerance. The use of kinematic parameters of the head to predict brain injury has been suggested because they are indicative of the inertial response of the brain. The objective of this study is to characterize the rotational kinematics of the head associated with concussive impacts using a large head acceleration dataset collected from human subjects. The helmets of 335 football players were instrumented with accelerometer arrays that measured head acceleration following head impacts sustained during play, resulting in data for 300,977 sub-concussive and 57 concussive head impacts. The average sub-concussive impact had a rotational acceleration of 1230 rad/s² and a rotational velocity of 5.5 rad/s, while the average concussive impact had a rotational acceleration of 5022 rad/s² and a rotational velocity of 22.3 rad/s. An injury risk curve was developed and a nominal injury value of 6383 rad/s² associated with 28.3 rad/s represents 50% risk of concussion. These data provide an increased understanding of the biomechanics associated with concussion and they provide critical insight into injury mechanisms, human tolerance to mechanical stimuli, and injury prevention techniques.     

Effect of helmet liner systems and impact directions on severity of head injuries sustained in ballistic impacts: a finite element (FE) study

The current study aims to investigate the effectiveness of two different designs of helmet interior cushion, (Helmet 1: strap-netting; Helmet 2: Oregon Aero foam-padding), and the effect of the impact directions on the helmeted head during ballistic impact. Series of ballistic impact simulations (frontal, lateral, rear, and top) of a full-metal-jacketed bullet were performed on a validated finite element head model equipped with the two helmets, to assess the severity of head injuries sustained in ballistic impacts using both head kinematics and biomechanical metrics. Benchmarking with experimental ventricular and intracranial pressures showed that there is good agreement between the simulations and experiments. In terms of extracranial injuries, top impact had the highest skull stress, still without fracturing the skull. In regard to intracranial injuries, both the lateral and rear impacts generally gave the highest principal strains as well as highest shear strains, which exceed the injury thresholds. Off-cushion impacts were found to be at higher risk of intracranial injuries. The study also showed that the Oregon Aero foam pads helped to reduce impact forces. It also suggested that more padding inserts of smaller size may offer better protection. This provides some insights on future’s helmet design against ballistic threats.