Journal articles on the topic 'Head acceleration exposure'
To see the other types of publications on this topic, follow the link: Head acceleration exposure.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Head acceleration exposure.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Basinas, Ioannis, Damien M. McElvenny, Neil Pearce, Valentina Gallo, and John W. Cherrie. "A Systematic Review of Head Impacts and Acceleration Associated with Soccer." International Journal of Environmental Research and Public Health 19, no. 9 (May 1, 2022): 5488. http://dx.doi.org/10.3390/ijerph19095488.
Full textAbstract:
Epidemiological studies of the neurological health of former professional soccer players are being undertaken to identify whether heading the ball is a risk factor for disease or premature death. A quantitative estimate of exposure to repeated sub-concussive head impacts would provide an opportunity to investigate possible exposure-response relationships. However, it is unclear how to formulate an appropriate exposure metric within the context of epidemiological studies. We have carried out a systematic review of the scientific literature to identify the factors that determine the magnitude of head impact acceleration during experiments and from observations during playing or training for soccer, up to the end of November 2021. Data were extracted from 33 experimental and 27 observational studies from male and female amateur players including both adults and children. There was a high correlation between peak linear and angular accelerations in the observational studies (p < 0.001) although the correlation was lower for the experimental data. We chose to rely on an analysis of maximum or peak linear acceleration for this review. Differences in measurement methodology were identified as important determinants of measured acceleration, and we concluded that only data from accelerometers fixed to the head provided reliable information about the magnitude of head acceleration from soccer-related impacts. Exposures differed between men and women and between children and adults, with women on average experiencing higher acceleration but less frequent impacts. Playing position appears to have some influence on the number of heading impacts but less so on the magnitude of the head acceleration. Head-to-head collisions result in high levels of exposure and thus probably risk causing a concussion. We concluded, in the absence of evidence to the contrary, that estimates of the cumulative number of heading impacts over a playing career should be used as the main exposure metric in epidemiological studies of professional players.
2
Gellner, Ryan A., Eamon T. Campolettano, Eric P. Smith, and Steven Rowson. "Are specific players more likely to be involved in high-magnitude head impacts in youth football?" Journal of Neurosurgery: Pediatrics 24, no. 1 (July 2019): 47–53. http://dx.doi.org/10.3171/2019.2.peds18176.
Full textAbstract:
OBJECTIVEYouth football attracts approximately 3.5 million participants every year, but concern has recently arisen about the long-term effects of experiencing repetitive head accelerations from a young age due to participation in football. The objective of this study was to quantify total involvement in high-magnitude impacts among individual players in youth football practices. The authors explored the relationship between the total number of high-magnitude accelerations in which players were involved (experienced either by themselves or by other players) during practices and the number of high-magnitude accelerations players experienced.METHODSA local cohort of 94 youth football players (mean age 11.9 ± 1.5, mean body mass 50.3 ± 16.4 kg) from 4 different teams were recruited and outfitted with helmet-mounted accelerometer arrays. The teams were followed for one season each for a total of 128 sessions (practices, games, and scrimmages). All players involved in high-magnitude (greater than 40g) head accelerations were subsequently identified through analysis of practice film.RESULTSPlayers who experienced more high-magnitude accelerations were more likely to be involved in impacts associated with high-magnitude accelerations in other players. A small subset of 6 players (6%) were collectively involved in 230 (53%) high-magnitude impacts during practice, were involved in but did not experience a high-magnitude acceleration 78 times (21% of the 370 one-sided high-magnitude impacts), and experienced 152 (30%) of the 502 high-magnitude accelerations measured. Quarterbacks/running backs/linebackers were involved in the greatest number of high-magnitude impacts in practice and experienced the greatest number of high-magnitude accelerations. Which team a player was on was an important factor, as one team showed much greater head impact exposure than all others.CONCLUSIONSThis study showed that targeting the most impact-prone players for individualized interventions could reduce high-magnitude acceleration exposure for entire teams. These data will help to further quantify elevated head acceleration exposure and enable data-driven interventions that modify exposure for individual players and entire teams.
3
Swenson, Abigail, Logan Miller, Jillian Urban, and Joel Stitzel. "Head Kinematics by Contact Scenarios in Youth Ice Hockey." Neurology 95, no. 20 Supplement 1 (November 16, 2020): S1.1—S1. http://dx.doi.org/10.1212/wnl.0000000000011045.
Full textAbstract:
ObjectiveThe objective of this pilot study was to characterize head impact exposure in a sample of youth boys' ice hockey using a novel instrumented mouthpiece, improving accuracy.BackgroundFrom 2010 to 2018 youth ice hockey saw a 15% increase in participation, despite growing concerns for concussion risk in contact sports. While contact sports with similar rates of concussion have been subjected to rigorous study, head impact exposure in youth ice hockey has been largely underexplored. Existing youth studies have utilized helmet-mounted sensors, which are associated with error due to poor coupling with the skull.Design/MethodsCustom mouthpieces containing a tri-axial accelerometer and gyroscope were fit to seven enrolled athletes, and monitored during practices and games throughout the season. Linear acceleration and rotational velocity of the head were recorded for 60 ms when 5 g was exceeded on any axis for at least 3 ms. Time-synchronized film was reviewed to identify the contact scenario and head contact. Summary statistics of kinematics were calculated by scenario and presence of head contact.ResultsA total of 465 events were recorded over 25 weeks. Of these events 25% involved head contact; 92% of all contact scenarios were board checks, falls, or ice checks. Events involving head contact (i.e., head impacts) had median [95th percentile] peak linear acceleration, rotational velocity, and angular acceleration of 8.1 [30.9] g, 7.9 [20.2] rad/s, and 614 [2673] rad/s2, respectively. Events not involving head contact had median [95th percentile] peak linear acceleration, rotational velocity, and angular acceleration of 6.6 [43.8] g, 6.5 [17.5] rad/s, and 455 [4115] rad/s2, respectively.ConclusionsThe majority of the recorded events could be classified as board checks, falls, or ice checks. Median peak kinematics were higher for head impacts than non-head impact events. In contrast, 95th percentile linear and angular accelerations were greater for impacts not involving head contact.
4
Bellamkonda, Srinidhi, Samantha J. Woodward, Eamon Campolettano, Ryan Gellner, Mireille E. Kelley, Derek A. Jones, Amaris Genemaras, et al. "Head Impact Exposure in Practices Correlates With Exposure in Games for Youth Football Players." Journal of Applied Biomechanics 34, no. 5 (October 1, 2018): 354–60. http://dx.doi.org/10.1123/jab.2017-0207.
Full textAbstract:
This study aimed to compare head impact exposures between practices and games in football players ages 9 to 14 years, who account for approximately 70% of all football players in the United States. Over a period of 2 seasons, 136 players were enrolled from 3 youth programs, and 49,847 head impacts were recorded from 345 practices and 137 games. During the study, individual players sustained a median of 211 impacts per season, with a maximum of 1226 impacts. Players sustained 50th (95th) percentile peak linear acceleration of 18.3 (46.9) g, peak rotational acceleration of 1305.4 (3316.6) rad·s−2, and Head Impact Technology Severity Profile of 13.7 (24.3), respectively. Overall, players with a higher frequency of head impacts at practices recorded a higher frequency of head impacts at games (P < .001,r2 = .52), and players who sustained a greater average magnitude of head impacts during practice also recorded a greater average magnitude of head impacts during games (P < .001). The youth football head impact data quantified in this study provide valuable insight into the player exposure profile, which should serve as a key baseline in efforts to reduce injury.
5
Lamond, Lindsey C., Jaclyn B. Caccese, Thomas A. Buckley, Joseph Glutting, and Thomas W. Kaminski. "Linear Acceleration in Direct Head Contact Across Impact Type, Player Position, and Playing Scenario in Collegiate Women's Soccer Players." Journal of Athletic Training 53, no. 2 (February 1, 2018): 115–21. http://dx.doi.org/10.4085/1062-6050-90-17.
Full textAbstract:
Context: Heading, an integral component of soccer, exposes athletes to a large number of head impacts over a career. The literature has begun to indicate that cumulative exposure may lead to long-term functional and psychological deficits. Quantifying an athlete's exposure over a season is a first step in understanding cumulative exposure. Objective: To measure the frequency and magnitude of direct head impacts in collegiate women's soccer players across impact type, player position, and game or practice scenario. Design: Cross-sectional study. Setting: National Collegiate Athletic Association Division I institution. Patients or Other Participants: Twenty-three collegiate women's soccer athletes. Main Outcome Measure(s): Athletes wore Smart Impact Monitor accelerometers during all games and practices. Impacts were classified during visual, on-field monitoring of athletic events. All direct head impacts that exceeded the 10g threshold were included in the final data analysis. The dependent variable was linear acceleration, and the fixed effects were (1) type of impact: clear, pass, shot, unintentional deflection, or head-to-head contact; (2) field position: goalkeeper, defense, forward, or midfielder; (3) playing scenario: game or practice. Results: Shots (32.94g ± 12.91g, n = 38; P = .02) and clears (31.09g ± 13.43g, n = 101; P = .008) resulted in higher mean linear accelerations than passes (26.11g ± 15.48g, n = 451). Head-to-head impacts (51.26g ± 36.61g, n = 13; P < .001) and unintentional deflections (37.40g ± 34.41g, n = 24; P = .002) resulted in higher mean linear accelerations than purposeful headers (ie, shots, clears, and passes). No differences were seen in linear acceleration across player position or playing scenario. Conclusions: Nonheader impacts, including head-to-head impacts and unintentional deflections, resulted in higher mean linear accelerations than purposeful headers, including shots, clears, and passes, but occurred infrequently on the field. Therefore, these unanticipated impacts may not add substantially to an athlete's cumulative exposure, which is a function of both frequency and magnitude of impact.
6
Crisco, Joseph J., Bethany J. Wilcox, Jason T. Machan, Thomas W. McAllister, Ann-Christine Duhaime, Stefan M. Duma, Steven Rowson, Jonathan G. Beckwith, Jeffrey J. Chu, and Richard M. Greenwald. "Magnitude of Head Impact Exposures in Individual Collegiate Football Players." Journal of Applied Biomechanics 28, no. 2 (May 2012): 174–83. http://dx.doi.org/10.1123/jab.28.2.174.
Full textAbstract:
The purpose of this study was to quantify the severity of head impacts sustained by individual collegiate football players and to investigate differences between impacts sustained during practice and game sessions, as well as by player position and impact location. Head impacts (N = 184,358) were analyzed for 254 collegiate players at three collegiate institutions. In practice, the 50th and 95th percentile values for individual players were 20.0 g and 49.5 g for peak linear acceleration, 1187 rad/s2 and 3147 rad/s2 for peak rotational acceleration, and 13.4 and 29.9 for HITsp, respectively. Only the 95th percentile HITsp increased significantly in games compared with practices (8.4%, p = .0002). Player position and impact location were the largest factors associated with differences in head impacts. Running backs consistently sustained the greatest impact magnitudes. Peak linear accelerations were greatest for impacts to the top of the helmet, whereas rotational accelerations were greatest for impacts to the front and back. The findings of this study provide essential data for future investigations that aim to establish the correlations between head impact exposure, acute brain injury, and long-term cognitive deficits.
7
DiGuglielmo, Daniella M., Mireille E. Kelley, Mark A. Espeland, Zachary A. Gregory, Tanner D. Payne, Derek A. Jones, Tanner M. Filben, Alexander K. Powers, Joel D. Stitzel, and Jillian E. Urban. "The Effect of Player Contact Characteristics on Head Impact Exposure in Youth Football Games." Journal of Applied Biomechanics 37, no. 2 (April 1, 2021): 145–55. http://dx.doi.org/10.1123/jab.2020-0145.
Full textAbstract:
To reduce head impact exposure (HIE) in youth football, further understanding of the context in which head impacts occur and the associated biomechanics is needed. The objective of this study was to evaluate the effect of contact characteristics on HIE during player versus player contact scenarios in youth football. Head impact data and time-synchronized video were collected from 4 youth football games over 2 seasons in which opposing teams were instrumented with the Head Impact Telemetry (HIT) System. Coded contact characteristics included the player’s role in the contact, player speed and body position, contact height, type, and direction, and head contact surface. Head accelerations were compared among the contact characteristics using mixed-effects models. Among 72 instrumented athletes, 446 contact scenarios (n = 557 impacts) with visible opposing instrumented players were identified. When at least one player had a recorded impact, players who were struck tended to have higher rotational acceleration than players in striking positions. When both players had a recorded impact, lighter players and taller players experienced higher mean head accelerations compared with heavier players and shorter players. Understanding the factors influencing HIE during contact events in football may help inform methods to reduce head injury risk.
8
Kelley, Mireille E., Joeline M. Kane, Mark A. Espeland, Logan E. Miller, Alexander K. Powers, Joel D. Stitzel, and Jillian E. Urban. "Head impact exposure measured in a single youth football team during practice drills." Journal of Neurosurgery: Pediatrics 20, no. 5 (November 2017): 489–97. http://dx.doi.org/10.3171/2017.5.peds16627.
Full textAbstract:
OBJECTIVEThis study evaluated the frequency, magnitude, and location of head impacts in practice drills within a youth football team to determine how head impact exposure varies among different types of drills.METHODSOn-field head impact data were collected from athletes participating in a youth football team for a single season. Each athlete wore a helmet instrumented with a Head Impact Telemetry (HIT) System head acceleration measurement device during all preseason, regular season, and playoff practices. Video was recorded for all practices, and video analysis was performed to verify head impacts and assign each head impact to a specific drill. Eleven drills were identified: dummy/sled tackling, install, special teams, Oklahoma, one-on-one, open-field tackling, passing, position skill work, multiplayer tackle, scrimmage, and tackling drill stations. Generalized linear models were fitted to log-transformed data, and Wald tests were used to assess differences in head accelerations and impact rates.RESULTSA total of 2125 impacts were measured during 30 contact practices in 9 athletes (mean age 11.1 ± 0.6 years, mean mass 44.9 ± 4.1 kg). Open-field tackling had the highest median and 95th percentile linear accelerations (24.7g and 97.8g, respectively) and resulted in significantly higher mean head accelerations than several other drills. The multiplayer tackle drill resulted in the highest head impact frequency, with an average of 0.59 impacts per minute per athlete, but the lowest 95th percentile linear accelerations of all drills. The front of the head was the most common impact location for all drills except dummy/sled tackling.CONCLUSIONSHead impact exposure varies significantly in youth football practice drills, with several drills exposing athletes to high-magnitude and/or high-frequency head impacts. These data suggest that further study of practice drills is an important step in developing evidence-based recommendations for modifying or eliminating certain high-intensity drills to reduce head impact exposure and injury risk for all levels of play.
9
Tierney, Gregory, Daniel Weaving, James Tooby, Marwan Al-Dawoud, Sharief Hendricks, Gemma Phillips, Keith A. Stokes, Kevin Till, and Ben Jones. "Quantifying head acceleration exposure via instrumented mouthguards (iMG): a validity and feasibility study protocol to inform iMG suitability for the TaCKLE project." BMJ Open Sport & Exercise Medicine 7, no. 3 (September 2021): e001125. http://dx.doi.org/10.1136/bmjsem-2021-001125.
Full textAbstract:
Instrumented mouthguards (iMGs) have the potential to quantify head acceleration exposures in sport. The Rugby Football League is looking to deploy iMGs to quantify head acceleration exposures as part of the Tackle and Contact Kinematics, Loads and Exposure (TaCKLE) project. iMGs and associated software platforms are novel, thus limited validation studies exist. The aim of this paper is to describe the methods that will determine the validity (ie, laboratory validation of kinematic measures and on-field validity) and feasibility (ie, player comfort and wearability and practitioner considerations) of available iMGs for quantifying head acceleration events in rugby league. Phase 1 will determine the reliability and validity of iMG kinematic measures (peak linear acceleration, peak rotational velocity, peak rotational acceleration), based on laboratory criterion standards. Players will have three-dimensional dental scans and be provided with available iMGs for phase 2 and phase 3. Phase 2 will determine the on-field validity of iMGs (ie, identifying true positive head acceleration events during a match). Phase 3 will evaluate player perceptions of fit (too loose, too tight, bulky, small/thin, held mouth open, held teeth apart, pain in jaw muscles, uneven bite), comfort (on lips, gum, tongue, teeth) and function (speech, swallowing, dry mouth). Phase 4 will evaluate the practical feasibility of iMGs, as determined by practitioners using the system usability scale (preparing iMG system and managing iMG data). The outcome will provide a systematic and robust assessment of a range of iMGs, which will help inform the suitability of each iMG system for the TaCKLE project.
10
Randjelovic, Danijela, and Miroslav Pavlovic. "The effect of acceleration on color vision." Vojnosanitetski pregled 75, no. 6 (2018): 623–31. http://dx.doi.org/10.2298/vsp160622288r.
Full textAbstract:
Background/Aim. Over 80% of all information a pilot receives during the flight is visual with color perception being one of the most important visual functions for managing an aircraft. The reception of color is of high significance in aviation due to the importance of signal tracking on instrument panels as well as the importance of visual stimulus and environment signs. There is no sufficient number of papers and studies that deal with this issue, although recent studies have shown that the connection between acceleration and color perception exists. The aim of this study was to demonstrate the correlation between pilot exposure to +Gz acceleration in human centrifuge and color perception before and after acceleration exposure. Methods. Subjects of the study were 40 military pilots, aged 35?45, with 10 and 20 years of flying experience. Pilots were exposed to +Gz acceleration (inertial force acts from head to feet) in the human centrifuge for pilot training with accelerations of +2Gz, +5.5Gz up to +7Gz. The tests focused on color perception before and after the exposure to the acceleration. Results. Out of 40 pilots examined for color vision, in 35 (87.50%) had normal results in color identification before and after +Gz; 5.00% (2 subjects) had two mistakes ? reading number 5 instead of number 3, which falls within the normal trichomes, and reading number 16 instead of number 26. Three subjects (7.50%) gave their answers slower than the accepted response time. After the +7Gz exposure, 34 (85%) persons had normal results in color identification, 2 (5%) subjects made three mistakes ? at numbers 5, 74 and 26; one (2.50%) pilot made four mistakes on numbers 5, 7, 74 and 26; 7.50% (3 pilots) of the subjects identified colors slower. Conclusion. Color perception in pilots is unstable on high +Gz accelerations. Exposure to +5.5Gz acceleration does not lead to significant changes in color perception, while exposure to +7Gz acceleration showed a significant percentage of reversible disturbance in color perception which lasted for 10 minutes.
11
Urban, Jillian, Mirellie Kelley, Mark Espeland, Elizabeth Davenport, Christopher T. Whitlow, Alexander Powers, Joseph Maldjian, and Joel Stitzel. "In-season variations in head impact exposure among youth football players." Neurology 91, no. 23 Supplement 1 (December 4, 2018): S1.3—S2. http://dx.doi.org/10.1212/01.wnl.0000550621.28386.81.
Full textAbstract:
Sport-related head impacts are of increasing concern as early evidence has demonstrated a relationship between subconcussive head impact exposure (HIE) experienced in contact sports, such as football, and changes in pre-to post-season imaging and cognitive measures. Cumulative HIE is often measured with a single number that amounts to the total exposure measured over the season and does not give any indication as to how the exposure was accumulated, nor how it varies during the season. Therefore, the objective of this study was to compare HIE during preseason, the first and second halves of the regular season, and playoffs in a sample of youth football players (n = 119, ages 9–13). Athletes were divided into 1 of 4 exposure groups based on quartiles computed from the distribution of risk-weighted cumulative exposure (RWECP). The mean 95th percentile linear and rotational accelerations and impacts per session in practices and games were compared across 4 exposure groups and time frames using mixed effects models. Within games, the sample mean 95th percentile linear and rotational accelerations ranged from 47.2 g and 2,331.3 rad/s2 during preseason to 52.1 g and 2,533.4 rad/s2 during the second half of regular season. Mean impacts per practice increased from preseason to the second half of regular season and declined into playoffs among all exposure groups; however, the variation between time frames was not greater than 2 impacts per practice. Time of season had a significant effect on mean 95th percentile linear and rotational acceleration in games (both p = 0.01) but not on practice accelerations or impacts/session. Mean 95th percentile accelerations for games showed significant interaction effects between exposure group and season segment (linear p = 0.05 and rotational p = 0.04). The results of this study improve our understanding of in-season variations in youth football HIE and may inform important opportunities for future interventions.
12
Blouin, Jean-Sébastien, Gunter P. Siegmund, and J. Timothy Inglis. "Interaction between acoustic startle and habituated neck postural responses in seated subjects." Journal of Applied Physiology 102, no. 4 (April 2007): 1574–86. http://dx.doi.org/10.1152/japplphysiol.00703.2006.
Full textAbstract:
Postural and startle responses rapidly habituate with repeated exposures to the same stimulus, and the first exposure to a seated forward acceleration elicits a startle response in the neck muscles. Our goal was to examine how the acoustic startle response is integrated with the habituated neck postural response elicited by forward accelerations of seated subjects. In experiment 1, 14 subjects underwent 11 sequential forward accelerations followed by 5 additional sled accelerations combined with a startling tone (124-dB sound pressure level) initiated 18 ms after sled acceleration onset. During the acceleration-only trials, changes consistent with habituation occurred in the root-mean-square amplitude of the neck muscles and in the peak amplitude of five head and torso kinematic variables. The subsequent addition of the startling tone restored the amplitude of the neck muscles and four of the five kinematic variables but shortened onset of muscle activity by 9–12 ms. These shortened onset times were further explored in experiment 2, wherein 16 subjects underwent 11 acceleration-only trials followed by 15 combined acceleration-tone trials with interstimulus delays of 0, 13, 18, 23, and 28 ms. Onset times shortened further for the 0- and 13-ms delays but did not lengthen for the 23- and 28-ms delays. These temporal and spatial changes in EMG can be explained by a summation of the excitatory drive converging at or before the neck muscle motoneurons. The present observations suggest that habituation to repeated sled accelerations involves extinguishing the startle response and tuning the postural response to the whole body disturbance.
13
Campolettano, Eamon T., Steven Rowson, and Stefan M. Duma. "Drill-specific head impact exposure in youth football practice." Journal of Neurosurgery: Pediatrics 18, no. 5 (November 2016): 536–41. http://dx.doi.org/10.3171/2016.5.peds1696.
Full textAbstract:
OBJECTIVE Although 70% of football players in the United States are youth players (6–14 years old), most research on head impacts in football has focused on high school, collegiate, or professional populations. The objective of this study was to identify the specific activities associated with high-magnitude (acceleration > 40g) head impacts in youth football practices. METHODS A total of 34 players (mean age 9.9 ± 0.6 years) on 2 youth teams were equipped with helmet-mounted accelerometer arrays that recorded head accelerations associated with impacts in practices and games. Videos of practices and games were used to verify all head impacts and identify specific drills associated with each head impact. RESULTS A total of 6813 impacts were recorded, of which 408 had accelerations exceeding 40g (6.0%). For each type of practice drill, impact rates were computed that accounted for the length of time that teams spent on each drill. The tackling drill King of the Circle had the highest impact rate (95% CI 25.6–68.3 impacts/hr). Impact rates for tackling drills (those conducted without a blocker [95% CI 14.7–21.9 impacts/hr] and those with a blocker [95% CI 10.5–23.1 impacts/hr]) did not differ from game impact rates (95% CI 14.2–21.6 impacts/hr). Tackling drills were observed to have a greater proportion (between 40% and 50%) of impacts exceeding 60g than games (25%). The teams in this study participated in tackling or blocking drills for only 22% of their overall practice times, but these drills were responsible for 86% of all practice impacts exceeding 40g. CONCLUSIONS In youth football, high-magnitude impacts occur more often in practices than games, and some practice drills are associated with higher impact rates and accelerations than others. To mitigate high-magnitude head impact exposure in youth football, practices should be modified to decrease the time spent in drills with high impact rates, potentially eliminating a drill such as King of the Circle altogether.
14
Kelley, Mireille E., Mark A. Espeland, William C. Flood, Alexander K. Powers, Christopher T. Whitlow, Joseph A. Maldjian, Joel D. Stitzel, and Jillian E. Urban. "Comparison of head impact exposure in practice drills among multiple youth football teams." Journal of Neurosurgery: Pediatrics 23, no. 3 (March 2019): 381–89. http://dx.doi.org/10.3171/2018.9.peds18314.
Full textAbstract:
OBJECTIVELimiting contact in football practice can reduce the number of head impacts a player receives, but further research is needed to inform the modification of optimal drills that mitigate head impact exposure (HIE) while the player develops the skills needed to safely play the game. This study aimed to compare HIE in practice drills among 6 youth football teams and to evaluate the effect of a team on HIE.METHODSOn-field head impact data were collected from athletes (ages 10–13 years) playing on 6 local youth football teams (teams A–F) during all practices using the Head Impact Telemetry System. Video was recorded and analyzed to verify and assign impacts to a specific drill. Drills were identified as follows: dummy/sled tackling, half install, install, install walk through, multiplayer tackle, Oklahoma, one-on-one, open field tackling, other, passing, position skill work, scrimmage, special teams, tackling drill stations, and technique. HIE was quantified in terms of impacts per player per minute (ppm) and peak linear and rotational head acceleration. Generalized linear models were used to assess differences in head impact magnitude and frequency among drills as well as among teams within the most common drills.RESULTSAmong 67 athlete-seasons, a total of 14,718 impacts during contact practices were collected and evaluated in this study. Among all 6 teams, the mean linear (p < 0.0001) and rotational (p < 0.0001) acceleration varied significantly among all drills. Open field tackling had significantly (p < 0.001) higher mean linear acceleration than all other drills. Multiplayer tackle had the highest mean impact rate (0.35 ppm). Significant variations in linear acceleration and impact rate were observed among teams within specific drills. Team A had the highest mean linear acceleration in install, one-on-one, and open field tackling and the highest mean impact rate in Oklahoma and position skill work. Although team A spent the greatest proportion of their practice on minimal- or no-player versus player contact drills (27%) compared to other teams, they had the highest median (20.2g) and 95th percentile (56.4g) linear acceleration in practice.CONCLUSIONSFull-speed tackling and blocking drills resulted in the highest HIE. Reducing time spent on contact drills relative to minimal or no contact drills may not lower overall HIE. Instead, interventions such as reducing the speed of players engaged in contact, correcting tackling technique, and progressing to contact may reduce HIE more effectively.
15
Lempke, Landon B., A. Faith Bartello, Melissa N. Anderson, Rachel S. Johnson, Julianne D. Schmidt, and Robert C. Lynall. "COMPARISON OF HEAD IMPACT BIOMECHANICS BETWEEN TACKLE AND FLAG YOUTH FOOTBALL." Orthopaedic Journal of Sports Medicine 7, no. 3_suppl (March 1, 2019): 2325967119S0000. http://dx.doi.org/10.1177/2325967119s00001.
Full textAbstract:
Background: There is growing fear among healthcare professionals and parents regarding youth tackle football, likely due to highly publicized concerns about potential long-term physical and cognitive health of professional football players. Parents and advocacy groups are pushing for state legislation to ban youth tackle football in favor of flag football to avoid repetitive head impacts that are potentially associated with late-life cognitive deficits. Although the head impact burden experienced during flag football is likely lower than tackle, no research has compared head impact exposure between youth tackle and flag football. Therefore, our purpose was to examine head impact exposure and magnitudes between youth tackle and flag football players. Methods: Twenty-seven tackle (age=11.0±1.5y, height=145.8±11.9 cm, mass=45.0±14.9 kg) and 29 flag football players (age=8.6±1.1y, height=133.9±8.4 cm, mass=33.9±9.5 kg) were enrolled in this prospective cohort study. Participants were fitted with head impact sensors (Triax Sim-G) worn throughout the entire 2017 season that recorded impact frequency and magnitude (linear [g] and rotational acceleration [rad/s2]). Athlete exposure was defined as one player participating in one session. Impact rates (IR) were calculated as impacts per one athlete exposure. Game, practice, and combined IR were compared between groups using impact rate ratios (IRR). IRR with 95% confidence intervals (CI) not containing 1.0 were considered statistically significant. Acceleration values were binned into low- and high-magnitude categories (linear split at 40 g, rotational split at 4,600rad/s2). Magnitude category frequencies were compared between groups using Chi-square test of association (p<0.05), and 90th percentile acceleration values are presented. Results: One-thousand nine-hundred and eight tackle (735 game, 1173 practice; 70.66 impacts/player) and 169 flag (101 game, 68 practice; 5.83 impacts/player) football head impacts were recorded. Tackle players experienced a higher impact rate during games versus practices (IRR=1.41; 95%CI:1.29 -1.55) while flag players experienced a lower impact rate (IRR=0.60; 95%CI:0.44-0.81). Practice and game head impacts combined resulted in tackle players (IR=3.06) accruing 4.61 times the impact rate (95%CI:3.94-5.40) of flag players (IR=0.66). Tackle players sustained a significantly greater head impact rate than flag players during games (tackle IR=3.83, flag IR=0.55; IRR=6.90; 95%CI:5.60-8.49) and practices (tackle IR=2.72, flag IR=0.93; IRR=2.91; 95%CI:2.28-3.72). Tackle 90th percentile linear acceleration was 53.32 g (median=32.50 g) and flag was 53.32 g (median=32.65 g). Tackle 90th percentile rotational acceleration was 7,000 rad/s2 (median=3,200rad/s2) while flag was 8,300 rad/s2 (median=4,100rad/s2). Tackle experienced a significantly higher frequency of low-magnitude rotational acceleration impacts (71.6% vs. 57.4%) and lower frequency of high-magnitude impacts than flag (28.4% vs 42.6%;?2=15.15, p<0.001). There were no significant associations for linear acceleration (p=0.75). Conclusions/Significance: Our results indicate youth flag football head impact rates are 82%-88% lower compared to tackle. Contrary to general belief, youth flag football players experienced numerous head impacts with a greater tendency for high-magnitude rotational acceleration head impacts. Although fewer head impacts occur during youth flag football, parents and coaches should be aware that head impacts do occur during practices and games. Whether high-magnitude or high-frequency head impacts influence long-term health remains unknown. Our findings provide novel evidence into the head impact exposure occurring during youth tackle and flag football. Longitudinal studies examining head impact biomechanics and advanced neuroimaging in youth tackle and flag football players nationwide is warranted to ensure long term cognitive health.
16
Urban, Jillian E., William C. Flood, Barret J. Zimmerman, Mireille E. Kelley, Mark A. Espeland, Liam McNamara, Elizabeth M. Davenport, et al. "Evaluation of head impact exposure measured from youth football game plays." Journal of Neurosurgery: Pediatrics 24, no. 2 (August 2019): 190–99. http://dx.doi.org/10.3171/2019.2.peds18558.
Full textAbstract:
OBJECTIVEThere is a growing body of literature informing efforts to improve the safety of football; however, research relating on-field activity to head impacts in youth football is limited. Therefore, the objective of this study was to compare head impact exposure (HIE) measured in game plays among 3 youth football teams.METHODSHead impact and video data were collected from athletes (ages 10–13 years) participating on 3 youth football teams. Video analysis was performed to verify head impacts and assign each to a specific play type. Each play was categorized as a down, punt, kickoff, field goal, or false start. Kickoffs and punts were classified as special teams. Downs were classified as running, passing, or other. HIE was quantified by play type in terms of mean, median, and 95th percentile linear and rotational acceleration. Mixed-effects models were used to assess differences in acceleration among play types. Contact occurring on special teams plays was evaluated using a standardized video abstraction form.RESULTSA total of 3003 head impacts over 27.5 games were analyzed and paired with detailed video coding of plays. Most head impacts were attributed to running (79.6%), followed by passing (14.0%), and special teams (6.4%) plays. The 95th percentile linear acceleration measured during each play type was 52.6g, 50.7g, and 65.5g, respectively. Special teams had significantly greater mean linear acceleration than running and passing plays (both p = 0.03). The most common kick result on special teams was a deep kick, of which 85% were attempted to be returned. No special teams plays resulted in a touchback, and one resulted in a fair catch. One-third of all special teams plays and 92% of all nonreturned kicks resulted in athletes diving toward the ball.CONCLUSIONSThe results demonstrate a trend toward higher head impact magnitudes on special teams than for running and passing plays, but a greater number of impacts were measured during running plays. Deep kicks were most common on special teams, and many returned and nonreturned kicks resulted in athletes diving toward the ball. These results support policy changes to youth special teams plays, including modifying the yard line the ball is kicked from and coaching proper return technique. Further investigation into biomechanical exposure measured during game impact scenarios is needed to inform policy relevant to the youth level.
17
Pritchard, N. Stewart, and Jillian E. Urban. "AN ANALYSIS OF HEAD KINEMATICS IN WOMEN'S ARTISTIC GYMNASTICS." Science of Gymnastics Journal 12, no. 3 (November 3, 2022): 229–42. http://dx.doi.org/10.52165/sgj.12.3.229-242.
Full textAbstract:
Concussions in gymnastics have scarcely been researched; however, current evidence suggests that concussion rates may be higher than previously reported due to underreporting among coaches, athletes, and parents. The purpose of this study was to outline a method for collecting head impact data in gymnastics, and to provide the first measurements of head impact exposure within gymnastics. Three optional level women’s artistic gymnasts (ages 11-16) were instrumented with a mouthpiece sensor that measured linear acceleration, rotational velocity, and rotational acceleration of the head during contact and aerial phases of skills performed during practice. Peak linear acceleration, peakrotational velocity, peak rotational acceleration, duration, and time to peak linearacceleration were calculated from sensor data. Kinematic data was time-synchronized to videoand then sensor data was segmented into contact scenarios and skills characterized by theevent rotation, apparatus, landing mat type, skill type, skill phase, landing stability, andbody region contacted. The instrumented gymnasts were exposed to 1,394 contact scenarios(41 per gymnast per session), of which 114 (3.9 per gymnast per session) contained headcontact. Peak kinematics varied across skill type, apparatuses, and landing mats. The medianduration of impacts with head contact (177 ms) was longer than measured impacts in youth andcollegiate level soccer. Results from this study help provide a foundation for future researchthat may seek to examine head impact exposure within gymnastics to better informconcussion prevention and post-concussion return to play protocols within the sport.
18
Brooks, Jeffrey S., Kody R. Campbell, Wayne Allison, Andrew M. Johnson, and James P. Dickey. "Career Head Impact Exposure Profile of Canadian University Football Players." Journal of Applied Biomechanics 38, no. 1 (February 1, 2022): 47–57. http://dx.doi.org/10.1123/jab.2020-0228.
Full textAbstract:
This study quantified head impact exposures for Canadian university football players over their varsity career. Participants included 63 players from one team that participated in a minimum of 3 seasons between 2013 and 2018. A total of 127,192 head impacts were recorded from 258 practices and 65 games. The mean (SD) number of career impacts across all positions was 2023.1 (1296.4), with an average of 37.1 (20.3) impacts per game and 7.4 (4.4) impacts per practice. The number of head impacts that players experienced during their careers increased proportionally to the number of athletic exposures (P < .001, r = .57). Linebackers and defensive and offensive linemen experienced significantly more head impacts than defensive backs, quarterbacks, and wide receivers (P ≤ .014). Seniority did not significantly affect the number of head impacts a player experienced. Mean linear acceleration increased with years of seniority within defensive backs and offensive linemen (P ≤ .01). Rotational velocity increased with years of seniority within defensive backs, defensive and offensive linemen, running backs, and wide receivers (P < .05). These data characterize career metrics of head impact exposure for Canadian university football players and provide insights to reduce head impacts through rule modifications and contact regulations.
19
Blaxter, Laurence, Mildrid Yeo, Donal McNally, John Crowe, Caroline Henry, Sarah Hill, Neil Mansfield, Andrew Leslie, and Don Sharkey. "Neonatal head and torso vibration exposure during inter-hospital transfer." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 231, no. 2 (January 5, 2017): 99–113. http://dx.doi.org/10.1177/0954411916680235.
Full textAbstract:
Inter-hospital transport of premature infants is increasingly common, given the centralisation of neonatal intensive care. However, it is known to be associated with anomalously increased morbidity, most notably brain injury, and with increased mortality from multifactorial causes. Surprisingly, there have been relatively few previous studies investigating the levels of mechanical shock and vibration hazard present during this vehicular transport pathway. Using a custom inertial datalogger, and analysis software, we quantify vibration and linear head acceleration. Mounting multiple inertial sensing units on the forehead and torso of neonatal patients and a preterm manikin, and on the chassis of transport incubators over the duration of inter-site transfers, we find that the resonant frequency of the mattress and harness system currently used to secure neonates inside incubators is [Formula: see text]. This couples to vehicle chassis vibration, increasing vibration exposure to the neonate. The vibration exposure per journey (A(8) using the ISO 2631 standard) was at least 20% of the action point value of current European Union regulations over all 12 neonatal transports studied, reaching 70% in two cases. Direct injury risk from linear head acceleration (HIC15) was negligible. Although the overall hazard was similar, vibration isolation differed substantially between sponge and air mattresses, with a manikin. Using a Global Positioning System datalogger alongside inertial sensors, vibration increased with vehicle speed only above 60 km/h. These preliminary findings suggest there is scope to engineer better systems for transferring sick infants, thus potentially improving their outcomes.
20
Gellner, Ryan A., Eamon T. Campolettano, and Steven Rowson. "Does tackling form affect head acceleration in youth football players?" Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology 234, no. 3 (March 24, 2020): 257–67. http://dx.doi.org/10.1177/1754337120911497.
Full textAbstract:
To reduce head impact exposure, a number of youth football organizations have begun teaching tackling technique. This study sought to develop and utilize a set of tackling form grading criteria for both tacklers and ball carriers as well as to relate tackling form to head acceleration outcome. It was hypothesized that players exhibiting better form would experience lower head accelerations in individual tackles. Three teams consisting of 67 players (20, 29, and 18 players per team; age 12.7 ± 0.95, age range 11–14 years, body mass 55.1 ± 16.2 kg) were instrumented with helmet-mounted accelerometer arrays for one season. Videos of close-range tackling drills were used to develop tackling form criteria. Two raters used these criteria to each score 105 impacts. Six of the seven categories were found to have good inter-rater reliability metrics (total percent agreement ≥ 79%, agreement coefficient ≥ 0.65). Bending at both the hips and knees, leading with the shoulder or arm, and initiating contact were found to reduce risk of high-magnitude (>40 g) head impacts in tacklers. Keeping the eyes up and avoiding dropping the head reduced the risk of high-magnitude head impacts in ball carriers. This study shows the potential effectiveness of training both tacklers and ball carriers in proper technique for collisions in youth football to minimize head impacts.
21
Combs, Patricia R., Cassie B. Ford, Elizabeth F. Teel, Erin B. Wasserman, Michael J. Cools, and Jason P. Mihalik. "THE EFFECT OF A BODY CHECKING RULE CHANGE ON HEAD IMPACT BIOMECHANICS IN BANTAM ICE HOCKEY ATHLETES." Orthopaedic Journal of Sports Medicine 8, no. 4_suppl3 (April 1, 2020): 2325967120S0021. http://dx.doi.org/10.1177/2325967120s00215.
Full textAbstract:
Background: Body checking is the most common injury mechanism in ice hockey. Rule changes have sought to mitigate body checking exposure among youth players. In 2011, USA Hockey changed the legal body checking age from Pee Wee (11/12-year-olds) to Bantam (13/14-year-olds). Interestingly, Bantam players with checking experience during Pee Wee had a lower concussion risk relative to Bantam players without checking experience in a sample of Canadian youth hockey players. Understanding the head impact biomechanics underlying these findings could further elucidate the consequences of this rule change. Purpose: To determine the association between Pee Wee checking exposure and head impact biomechanics in a cohort of Bantam players. Methods: We prospectively collected data on Bantam ice hockey players during the 2006/07-2009/10 seasons and the 2012-2013 season. The 2006/07-2009/10 cohort (n= 61, age=13.9±0.5 years, height=168.2±8.7 cm, mass=59.9±10.4 kg) was allowed to body check (BC) as a Pee Wee player. The 2012-2013 cohort (n=15, age=13.3±0.4 years, height=167.5±7.4 cm, mass=57.5±8.6 kg) was not permitted to body check (NBC) as a Pee Wee player. Over the course of each season, head impacts were measured using in-helmet accelerometers. Only head impacts with linear acceleration ≥10 g were included in our analysis. Main outcome measures were mean linear acceleration (g) and rotational acceleration (rad/s2). Levene’s tests assessed equality of variance between groups. We employed mixed effects models to assess group differences in mean linear and rotational acceleration between BC and NBC groups. Results: The BC and NBC groups did not differ in height (t74=0.28, p=0.78) or mass (t74=0.84, p=0.40). When assessing group differences in head impact biomechanics, the NBC experienced significantly greater linear acceleration (F1,74=4.36, p=0.04) and greater rotational acceleration (F1,74=21.2, p<0.001) relative to the BC group. On average, the NBC group experienced 23.1 ± 0.87 g linear acceleration and 1993.5 ± 68.4 rad/s2 rotational acceleration compared to the BC group, which experienced 21.2 ± 0.30 g linear acceleration and 1615.9 ± 45.2 rad/s2 rotational acceleration. Conclusions: Bantam ice hockey players without body checking experience during their Pee Wee years experienced greater average linear and rotational acceleration relative to players with Pee Wee body checking experience. While removing body checking from Pee Wee ice hockey may reduce short-term injury risk, these athletes may demonstrate more high-risk head impact biomechanics when legally allowed to body check. Future research should continue to examine the influence of policy changes on head impact biomechanics and injury risk in youth ice hockey. [Figure: see text]
22
Huber, Colin M., Declan A. Patton, Susan Margulies, Christina Master, and Kristy Arbogast. "Head Impact Exposure and Mechanisms in Female High School Lacrosse via an Instrumented Mouthguard." Neurology 98, no. 1 Supplement 1 (December 27, 2021): S13.2—S14. http://dx.doi.org/10.1212/01.wnl.0000801856.45976.d2.
Full textAbstract:
ObjectiveTo quantify the head impact biomechanics, by impact mechanism, of female high school lacrosse players during games using an instrumented mouthguard.BackgroundThere is growing concern for the neurologic effects of repetitive head impacts in sports, which have been linked with several short-term neurophysiologic deficits. Girls' lacrosse represents a popular but understudied sport with regard to head impact exposure and current debate exists as to the need for enhanced protective equipment.Design/MethodsA female high school varsity lacrosse team wore the Stanford Instrumented Mouthguard during competitive games for the 2019 season. Video footage was reviewed to confirm head impact events and remove false-positive recordings. For each impact event, the mechanism was coded as stick contact, player contact, fall, or ball contact. Head impact rates were calculated per athlete exposure (AE, defined as a single player participating in a single game).ResultsSensor data were recorded for 15 female varsity lacrosse players for 14 games and 97 AEs. During games, 31 sensor-recorded head impacts were video-confirmed resulting in a pooled average head impact rate of 0.32 impacts/AE. The video-confirmed impacts were distributed between stick contact (17, 54.8%), player contact (12, 38.7%), and falls (2, 6.5%). There were no ball impacts. Overall peak kinematics were 34.0 ± 26.6 g, 12.0 ± 9.1 rad/s, and 3,666.5 ± 2,987.6 rad/s2. Stick contacts had the highest peak linear acceleration (42.7 ± 32.2 g), angular velocity (14.5 ± 11.1 rad/s), and angular acceleration (4,242.4 ± 3,634.9 rad/s2).ConclusionsStick impacts were the most common impact mechanism and resulted in the highest peak linear and angular kinematics, which may help explain why they are the most common cause of head injury in female lacrosse. By quantifying the head impact exposure, kinematics and mechanisms in female high school lacrosse, targeted injury preventions can be developed, such as rule changes and protective equipment.
23
Sandmo, Stian Bahr, Andrew S. McIntosh, Thor Einar Andersen, Inga Katharina Koerte, and Roald Bahr. "Evaluation of an In-Ear Sensor for Quantifying Head Impacts in Youth Soccer." American Journal of Sports Medicine 47, no. 4 (February 25, 2019): 974–81. http://dx.doi.org/10.1177/0363546519826953.
Full textAbstract:
Background: Wearable sensor systems have the potential to quantify head kinematic responses of head impacts in soccer. However, on-field use of sensors (eg, accelerometers) remains challenging, owing to poor coupling to the head and difficulties discriminating low-severity direct head impacts from inertial loading of the head from human movements, such as jumping and landing. Purpose: To test the validity of an in-ear sensor for quantifying head impacts in youth soccer. Study Design: Descriptive laboratory study. Methods: First, the sensor was mounted to a Hybrid III headform and impacted with a linear impactor or a soccer ball. Peak linear acceleration (PLA), peak rotational acceleration (PRA), and peak rotational velocity (PRV) were obtained from both systems; random and systematic errors were calculated with Hybrid III as reference. Then, 6 youth soccer players wore sensors and performed a structured training protocol, including heading and nonheading exercises; they also completed 2 regular soccer sessions. For each accelerative event recorded, PLA, PRA, and PRV outputs were compared with video recordings. Receiver operating characteristic curves were used to determine the sensor’s discriminatory capacity in both on-field settings, establishing cutoff values for predicting outcomes. Results: For the laboratory tests, the random error was 11% for PLA, 20% for PRA, and 5% for PRV; the systematic error was 11%, 19%, and 5%, respectively. For the structured training protocol, heading events resulted in higher absolute values (PLA = 15.6 g± 11.8 g) than nonheading events (PLA = 4.6 g± 1.2 g); the area under the curve was 0.98 for PLA. In regular training sessions, the area under the curve was >0.99 for PLA. A 9 g cutoff value yielded a positive predictive value of 100% in the structured training protocol versus 65% in the regular soccer sessions. Conclusion: The in-ear sensor displayed considerable random error and substantially overestimated head impact exposure. Despite the sensor’s excellent on-field accuracy for discriminating headings from other accelerative events in youth soccer, absolute values must be interpreted with caution, and there is a need for secondary means of verification (eg, video analysis) in real-life settings. Clinical Relevance: Wearable sensor systems can potentially provide valuable insights into head impact exposures in contact sports, but their limitations require careful consideration.
24
Broglio, Steven P., Richelle M. Williams, Kathryn L. O'Connor, and Jason Goldstick. "Football Players' Head-Impact Exposure After Limiting of Full-Contact Practices." Journal of Athletic Training 51, no. 7 (July 1, 2016): 511–18. http://dx.doi.org/10.4085/1062-6050-51.7.04.
Full textAbstract:
Context: Sporting organizations limit full-contact football practices to reduce concussion risk and based on speculation that repeated head impacts may result in long-term neurodegeneration. Objective: To directly compare head-impact exposure in high school football players before and after a statewide restriction on full-contact practices. Design: Cross-sectional study. Setting: High school football field. Patients or Other Participants: Participants were varsity football athletes from a single high school. Before the rule change, 26 athletes (age = 16.2 ± 0.8 years, height = 179.6 ± 6.4 cm, weight = 81.9 ± 13.1 kg) participated. After the rule change, 24 athletes (age = 15.9 ± 0.8 years, height = 178.3 ± 6.5 cm, weight = 76.2 ± 11.6 kg) participated. Nine athletes participated in both years of the investigation. Main Outcome Measure(s): Head-impact exposure was monitored using the Head Impact Telemetry System while the athletes participated in football games and practices in the seasons before and after the rule change. Head-impact frequency, location, and magnitude (ie, linear acceleration, rotational acceleration, and Head Impact Telemetry severity profile [HITsp], respectively) were measured. Results: A total of 15 398 impacts (592 impacts per player per season) were captured before the rule change and 8269 impacts (345 impacts per player per season) after the change. An average 42% decline in impact exposure occurred across all players, with practice-exposure declines occurring among linemen (46% decline); receivers, cornerbacks, and safeties (41% decline); and tight ends, running backs (including fullbacks), and linebackers (39% decline). Impact magnitudes remained largely unchanged between the years. Conclusions: A rule change limiting full-contact high school football practices appears to have been effective in reducing head-impact exposure across all players, with the largest reduction occurring among linemen. This finding is likely associated with the rule modification, particularly because the coaching staff and offensive scheme remained consistent, yet how this reduction influences concussion risk and long-term cognitive health remains unknown.
25
Eckner, James T., Kathryn L. O’Connor, Steven P. Broglio, and James A. Ashton-Miller. "Comparison of Head Impact Exposure Between Male and Female High School Ice Hockey Athletes." American Journal of Sports Medicine 46, no. 9 (June 1, 2018): 2253–62. http://dx.doi.org/10.1177/0363546518777244.
Full textAbstract:
Background: Concussion incidence rates are higher among female than male athletes in sports played by both sexes. Biomechanical factors may play a role in observed sex-based differences in concussion incidence. Purpose: To compare head impact counts and magnitudes during sports participation between male and female high school ice hockey athletes. Study Design: Cohort study; Level of evidence, 2. Methods: Over 2 seasons, a total of 21 male and 19 female ice hockey athletes from a single high school were instrumented with impact-sensing adhesive skin patches worn over the mastoid process while participating in games and practices. The impact sensors recorded the number, magnitude (peak linear acceleration [PLA, g] and peak angular acceleration [PAA, rad/s2] of the head; Head Impact Telemetry severity profile [HITsp]), and location of impacts sustained during each instrumented session. Head impact counts, magnitudes, and locations were compared between the sexes. Results: Males experienced more head impacts than females during games (mean ± SD: 7.7 ± 3.0 vs 5.3 ± 2.0, P < .001) as well as practices (4.3 ± 1.6 vs 3.8 ± 1.1, P = .002). Mean impact magnitudes were greater for females for PLA (18.8 g ± 1.7 g vs 17.1 g ± 1.6 g, P < .001) and HITsp (19.7 ± 1.5 vs 17.7 ± 1.4, P < .001), while mean PAA was greater for males (3057.6 ± 2.0 rad/s2 vs 2778.3 ± 2.7 rad/s2, P < .001). Female athletes experienced higher PLA, PAA, and HITsp magnitudes for the top 10%, 5%, and 1% of impacts (all P < .050). Males experienced more impacts to the front (34.3%) and back (31.7%) of the head, while females experienced more impacts to the side (43.1%) and top (4.1%) (χ2 = 295.70, df = 3, P < .001). Conclusion: While male high school ice hockey athletes experienced more head impacts than females, impact magnitudes tended to be higher for females.
26
Marks, Madison E., William C. Flood, Mireille E. Kelley, Mark A. Espeland, Christopher M. Miles, Alexander K. Powers, Christopher T. Whitlow, Joseph A. Maldjian, Joel D. Stitzel, and Jillian E. Urban. "Relationship between Aggressiveness, Self-Confidence, and Perceived Coach Support and Head Impact Exposure in Youth Football." Sports 10, no. 8 (July 29, 2022): 115. http://dx.doi.org/10.3390/sports10080115.
Full textAbstract:
This study evaluated head impact exposure (HIE) metrics in relation to individual-level determinants of HIE. Youth (n = 13) and high school (n = 21) football players were instrumented with the Head Impact Telemetry (HIT) system during one season. Players completed the Trait-Robustness of Self-Confidence Inventory (TROSCI), Sports Climate Questionnaire (SCQ), and Competitive Aggressiveness and Anger Scale (CAAS), measuring self-confidence, perceived coach support, and competitive aggressiveness, respectively. Relationships between HIE metrics (number of impacts, median and 95th percentile accelerations, and risk-weighted exposure (RWE)) and survey scores were evaluated using linear regression analysis. For middle school athletes, TROSCI scores were significantly negatively associated with the number of competition impacts and the mean number of impacts per player per competition. SCQ scores were significantly positively associated with median linear acceleration during practice. CAAS scores were not significantly associated with biomechanical metrics at either level of play. Perceived coach support and self-confidence might influence HIE among middle school football players. Football athletes’ competitive aggressiveness may have less influence their HIE than other factors.
27
Jansen, A. Elizabeth, Morgan McGrath, Sergey Samorezov, Joshua Johnston, Adam Bartsch, and Jay Alberts. "Characterizing Head Impact Exposure in Men and Women During Boxing and Mixed Martial Arts." Orthopaedic Journal of Sports Medicine 9, no. 12 (December 1, 2021): 232596712110598. http://dx.doi.org/10.1177/23259671211059815.
Full textAbstract:
Background: The accumulation of subconcussive impacts has been implicated in permanent neurological impairment. A gap in understanding the relationship between head impacts and neurological function is the lack of precise characterization and quantification of forces that individuals experience during sports training and competition. Purpose: To characterize impact exposure during training and competition among male and female athletes participating in boxing and mixed martial arts (MMA) via an instrumented custom-fit Impact Monitoring Mouthguard (IMM). Study Design: Cross-sectional study; Level of evidence, 3. Methods: Twenty-three athletes (n = 4 women) were provided a custom-fit IMM. The IMM monitored impacts during sparring and competition. All training and competition sessions were videotaped. Video and IMM data were synchronized for post hoc data verification of true positives and substantiation of impact location. IMM data were collected from boxing and MMA athletes at a collaborating site. For each true-positive impact, peak linear acceleration and peak angular acceleration were calculated. Wilcoxon rank sum tests were used to evaluate potential differences in sport, activity type, and sex with respect to each outcome. Differences in impact location were assessed via Kruskal-Wallis tests. Results: IMM data were collected from 53 amateur training sessions and 6 competitions (session range, 5-20 minutes). A total of 896 head impacts (men, n = 786; women, n = 110) were identified using IMM data and video verification: 827 in practice and 69 during competition. MMA and boxers experienced a comparable number of impacts per practice session or competition. In general, MMA impacts produced significantly higher peak angular acceleration than did boxing impacts ( P < .001) and were more varied in impact location on the head during competitions. In terms of sex, men experienced a greater number of impacts than women per practice session. However, there was no significant difference between men and women in terms of impact magnitude. Conclusion: Characteristic profiles of head impact exposure differed between boxing and MMA athletes; however, the impact magnitudes were not significantly different for male and female athletes.
28
Huibregtse, Megan E., Jonathan T. Macy, Jesse A. Steinfeldt, and Keisuke Kawata. "87842 The Effects of Head Impact Exposure on Changes in Neurocognitive and Oculomotor Function Across a High School American Football Season: A Pilot Study." Journal of Clinical and Translational Science 5, s1 (March 2021): 112. http://dx.doi.org/10.1017/cts.2021.687.
Full textAbstract:
ABSTRACT IMPACT: This work reveals the influence of a season of American football-related head impact exposure on two functional outcome measures in a cohort of adolescent boys, shedding light on the chronic effects of 'subconcussive head impacts.' OBJECTIVES/GOALS: To examine the influence of a season of exposure to head impacts in American football on changes in neurocognitive and oculomotor function in adolescent male athletes. METHODS/STUDY POPULATION: Participants were recruited from a local high school: the football group (FB; n = 26) was instrumented with sensor-installed mouthguards to track impact exposure during games and practices, and members of the men’s cross-country team were recruited to the control group (CON; n = 9). All participants were administered Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) and were assessed for near point of convergence (NPC) at pre- and post-season. Linear models will be fit for changes in the five ImPACT composite scores and NPC values, with group and one of the head impact variables as predictors for each model. In a secondary within-group analysis, correlation coefficients will be calculated for the relationships between the head impact variables and the functional change scores for the FB group. RESULTS/ANTICIPATED RESULTS: The two groups did not differ significantly on age or number of previous concussions; the CON group had significantly lower BMI. Group assignment was significantly associated with change in NPC (p < 0.05 for all three models); no significant associations were observed for any of the head impact variables with change in NPC. Group and each of the head impact variables (total impacts, sum of peak linear acceleration [PLA], and sum of peak rotational acceleration [PRA]) were not significantly associated with change in any of the five ImPACT composite scores. Change in visual memory composite score was negatively correlated with total impacts (r = -0.37, p = 0.034) and sum of PRA (r = -0.36, p = 0.040). DISCUSSION/SIGNIFICANCE OF FINDINGS: Significant, albeit relatively weak, correlations between change in visual memory composite score and two head impact kinematic variables, coupled with significant increases in NPC in the FB group compared to the CON group, suggest that a season of exposure to football-related head impacts has the potential to elicit minor functional impairments.
29
Reynolds, Bryson B., James Patrie, Erich J. Henry, Howard P. Goodkin, Donna K. Broshek, Max Wintermark, and T. Jason Druzgal. "Practice type effects on head impact in collegiate football." Journal of Neurosurgery 124, no. 2 (February 2016): 501–10. http://dx.doi.org/10.3171/2015.5.jns15573.
Full textAbstract:
OBJECT This study directly compares the number and severity of subconcussive head impacts sustained during helmet-only practices, shell practices, full-pad practices, and competitive games in a National Collegiate Athletic Association (NCAA) Division I-A football team. The goal of the study was to determine whether subconcussive head impact in collegiate athletes varies with practice type, which is currently unregulated by the NCAA. METHODS Over an entire season, a cohort of 20 collegiate football players wore impact-sensing mastoid patches that measured the linear and rotational acceleration of all head impacts during a total of 890 athletic exposures. Data were analyzed to compare the number of head impacts, head impact burden, and average impact severity during helmet-only, shell, and full-pad practices, and games. RESULTS Helmet-only, shell, and full-pad practices and games all significantly differed from each other (p ≤ 0.05) in the mean number of impacts for each event, with the number of impacts being greatest for games, then full-pad practices, then shell practices, and then helmet-only practices. The cumulative distributions for both linear and rotational acceleration differed between all event types (p < 0.01), with the acceleration distribution being similarly greatest for games, then full-pad practices, then shell practices, and then helmet-only practices. For both linear and rotational acceleration, helmet-only practices had a lower average impact severity when compared with other event types (p < 0.001). However, the average impact severity did not differ between any comparisons of shell and full-pad practices, and games. CONCLUSIONS Helmet-only, shell, and full-pad practices, and games result in distinct head impact profiles per event, with each succeeding event type receiving more impacts than the one before. Both the number of head impacts and cumulative impact burden during practice are categorically less than in games. In practice events, the number and cumulative burden of head impacts per event increases with the amount of equipment worn. The average severity of individual impacts is relatively consistent across event types, with the exception of helmet-only practices. The number of hits experienced during each event type is the main driver of event type differences in impact burden per athletic exposure, rather than the average severity of impacts that occur during the event. These findings suggest that regulation of practice equipment could be a fair and effective way to substantially reduce subconcussive head impact in thousands of collegiate football players.
30
Nawayseh, Naser, Hawra Al Sinan, Shamma Alteneiji, and Sadeque Hamdan. "Effect of gender on the biodynamic responses to vibration induced by a whole-body vibration training machine." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 233, no. 3 (March 2019): 383–92. http://dx.doi.org/10.1177/0954411919830122.
Full textAbstract:
Whole-body vibration training machines are used by both male and female users. However, studies investigating the biodynamic responses to vibration during training have used either mixed-gender subjects or male subjects. No study has investigated the effect of gender on the biodynamic responses under vibration training conditions. The objective of this study is to investigate the effect of gender on the apparent mass and the vibration of the head of standing people during exposure to vibration. A total of 40 subjects (20 females and 20 males) were exposed to vertical vibration at six frequencies in the range 20–45 Hz and vibration acceleration in the range 10.8–20.9 m/s2 (peak). The subjects stood on a force platform mounted on the vibrating plate of the machine adopting an upright standing posture with their knees unlocked and their arms straight along their bodies. The vertical acceleration and force at the interface between the vibrating plate and the feet were measured and used to calculate the apparent mass. The accelerations of the head in the x-, y- and z-directions were also measured and used to calculate the transmissibility to the head. The apparent mass of males was found higher than that of females. The transmissibility to the head in all directions was found higher in females than males. The differences in the biodynamic responses between males and females were attributed to the differences in body properties and structure of the two genders. The results of this study imply the need for gender-specific vibration training programmes.
31
Cross, Matthew J., Ross Tucker, Martin Raftery, Ben Hester, Sean Williams, Keith A. Stokes, Craig Ranson, Prav Mathema, and Simon Kemp. "Tackling concussion in professional rugby union: a case–control study of tackle-based risk factors and recommendations for primary prevention." British Journal of Sports Medicine 53, no. 16 (October 11, 2017): 1021–25. http://dx.doi.org/10.1136/bjsports-2017-097912.
Full textAbstract:
Background/aimConcussion, the most common injury in professional rugby union, occurs most commonly during the tackle. Thus, we investigated the association between tackle characteristics and concussion.Methods182 video clips of tackles leading to clinically diagnosed concussion and 4619 tackles that did not were coded across three professional rugby union competitions. A variable selection process was undertaken to identify the most important variables for interpretation. A multivariate generalised linear model was used to model the association between retained variables and concussion risk. Magnitude-based inferences provided an interpretation of the real-world relevance of the outcomes.ResultsThe four retained variables were: accelerating player, tackler speed, head contact type and tackle type. Overall, 70% of concussions occurred to the tackler and 30% to the ball carrier. There was a higher risk of concussion if the tackler accelerated into the tackle (OR: 2.49, 95% CI 1.70 to 3.64) or the tackler was moving at high speed (OR: 2.64, 95% CI 1.92 to 3.63). Head contact with the opposing player’s head (OR: 39.9, 95% CI 22.2 to 71.1) resulted in a substantially greater risk of concussion compared with all other head contact locations.ConclusionsInterventions that reduce the speed and acceleration of the tackler and reduce exposure to head-to-head contact would likely reduce concussion risk in professional rugby union.
32
Caccese, Jaclyn B., Lindsey C. Lamond, Thomas A. Buckley, and Thomas W. Kaminski. "Reducing purposeful headers from goal kicks and punts may reduce cumulative exposure to head acceleration." Research in Sports Medicine 24, no. 4 (September 6, 2016): 407–15. http://dx.doi.org/10.1080/15438627.2016.1230549.
Full text
33
Tooby, James, Dan Weaving, Marwan Al-Dawoud, and Gregory Tierney. "Quantification of Head Acceleration Events in Rugby League: An Instrumented Mouthguard and Video Analysis Pilot Study." Sensors 22, no. 2 (January 13, 2022): 584. http://dx.doi.org/10.3390/s22020584.
Full textAbstract:
Instrumented mouthguards (iMG) were used to collect head acceleration events (HAE) in men’s professional rugby league matches. Peak linear acceleration (PLA), peak angular acceleration (PAA) and peak change in angular velocity (ΔPAV) were collected using custom-fit iMG set with a 5 g single iMG-axis recording threshold. iMG were fitted to ten male Super League players for thirty-one player matches. Video analysis was conducted on HAE to identify the contact event; impacted player; tackle stage and head loading type. A total of 1622 video-verified HAE were recorded. Approximately three-quarters of HAE (75.7%) occurred below 10 g. Most (98.2%) HAE occurred during tackles (59.3% to tackler; 40.7% to ball carrier) and the initial collision stage of the tackle (43.9%). The initial collision stage resulted in significantly greater PAA and ΔPAV than secondary contact and play the ball tackle stages (p < 0.001). Indirect HAE accounted for 29.8% of HAE and resulted in significantly greater ΔPAV (p < 0.001) than direct HAE, but significantly lower PLA (p < 0.001). Almost all HAE were sustained in the tackle, with the majority occurring during the initial collision stage, making it an area of focus for the development of player protection strategies for both ball carriers and tacklers. League-wide and community-level implementation of iMG could enable a greater understanding of head acceleration exposure between playing positions, cohorts, and levels of play.
34
Shim, Sung Bo, Yeonghwan Bae, and Young Mo Koo. "Agility Comparison of Stabilizer and Direct Head Systems Mounted on an Unmanned Agricultural Helicopter." Transactions of the ASABE 61, no. 6 (2018): 1813–21. http://dx.doi.org/10.13031/trans.12650.
Full textAbstract:
Abstract. Recently, there has been increasing interest in using unmanned aerial vehicles (UAVs) to reduce the labor required for pest control and to protect farmers from exposure to pesticides. Unmanned aerial application has become a new paradigm in pesticide application; however, a uniform speed must be maintained within a short accelerating distance when spraying small plots, and this depends on the skill of the operator, which is difficult to rely on. In this study, the agility of a direct head system mounted on an unmanned agricultural helicopter was compared with that of a conventional stabilizer head system by using a pitch sweep test in CIFER, a dynamic analysis software program. The controllable frequency range of the unmanned agricultural helicopter with the direct head was analyzed to range between 0.06 and 5 Hz, and the responsiveness of the helicopter with the conventional stabilizer head was observed in a relatively low frequency range of 0.06 to 1.6 Hz. In addition, in comparing the equivalent time delay between the representative transfer functions from the pitch direction input to the surge acceleration obtained using NAVFIT analysis, the time delay of the direct head was shorter than that of the stabilizer head, although the extent of the enhancement was not satisfactory because of the tail gyroscope used for intrinsic attitude stability. Keywords: Agility, Agricultural unmanned helicopter, CIFER, Flight dynamics, Swash head system.
35
Hansson, Hans-Arne, Ulrika Krave, Svante Höjer, and Johan Davidsson. "Neck Flexion Induces Larger Deformation of the Brain Than Extension at a Rotational Acceleration, Closed Head Trauma." Advances in Neuroscience 2014 (November 3, 2014): 1–13. http://dx.doi.org/10.1155/2014/945869.
Full textAbstract:
A closed head trauma induces incompletely characterized temporary movement and deformation of the brain, contributing to the primary traumatic brain injury. We used the pressure patterns recorded with light-operated miniature sensors in anaesthetized adult rabbits exposed to a sagittal plane rotational acceleration of the head, lasting 1 ms, as a measure of brain deformation. Two exposure levels were used and scaled to correspond to force levels reported to cause mild and moderate diffuse injury in an adult man, respectively. Flexion induced transient, strong, extended, and predominantly negative pressures while extension generated a short positive pressure peak followed by a minor negative peak. Low level flexion caused as strong, extended negative pressures as did high level extension. Time differences were demonstrated between the deformation of the cerebrum, brainstem, and cerebellum. Available X-ray and MRI techniques do not have as high time resolution as pressure recordings in demonstrating complex, sequential compression and stretching of the brain during a trauma. The exposure to flexion caused more protracted and extensive deformation of the brain than extension, in agreement with a published histopathological report. The severity and extent of the brain deformation generated at a head trauma thus related to the direction at equal force.
36
Nooij, Suzanne A. E., Jelte E. Bos, and Eric L. Groen. "Orientation of Listing's plane after hypergravity in humans." Journal of Vestibular Research 18, no. 2-3 (December 26, 2008): 97–105. http://dx.doi.org/10.3233/ves-2008-182-303.
Full textAbstract:
Adaptation to a novel gravitational state involves adaptation of vestibular mediated responses, in particular those mediated by the otolith organs. The present paper investigates whether the orientation of Listing's plane, which is under control of otolith signals, is affected by sustained exposure to hypergravity. Subjects were exposed to four G-loads differing in duration (45 or 90 min) and magnitude (2 or 3G). During centrifugation subjects were in a supine position, directing the gravito-inertial acceleration along the naso-occipetal axis. We determined the orientation of Listing's plane before and after each centrifuge run, with the head erect and tilted in pitch. Head tilt in pitch induced a counter-pitch of Listing's plane, which was found to be less pronounced after centrifugation. In addition, exposure to 3G for 90~min induced a small backward tilt of Listing's plane compared to the pretest orientation (head erect). In order to explain these results a hypothesis is discussed, proposing that the orientation of Listing's plane in the head is governed by a head fixed orientation vector that is modulated by the direction of gravity relative to the head. Sustained centrifugation is proposed to decrease this gravitational modulation, leading to the effects observed. This could reflect a shift towards a more body centered frame of reference.
37
Reed, Nick, Tim Taha, Richard Greenwald, and Michelle Keightley. "Player and Game Characteristics and Head Impacts in Female Youth Ice Hockey Players." Journal of Athletic Training 52, no. 8 (August 1, 2017): 771–75. http://dx.doi.org/10.4085/1062-6050-52.5.04.
Full textAbstract:
Context: Despite the growing popularity of ice hockey among female youth and interest in the biomechanics of head impacts in sport, the head impacts sustained by this population have yet to be characterized. Objectives: To describe the number of, biomechanical characteristics of, and exposure to head impacts of female youth ice hockey players during competition and to investigate the influences of player and game characteristics on head impacts. Design: Cohort study. Methods: Twenty-seven female youth ice hockey players (mean age = 12.5 ± 0.52 years) wore instrumented ice hockey helmets during 66 ice hockey games over a 3-year period. Data specific to player, game, and biomechanical head impact characteristics were recorded. A multiple regression analysis identified factors most associated with head impacts of greater frequency and severity. Results: A total of 436 total head impacts were sustained during 6924 minutes of active ice hockey participation (0.9 ± 0.6 impacts per player per game; range, 0–2.1). A higher body mass index (BMI) significantly predicted a higher number of head impacts sustained per game (P = .008). Linear acceleration of head impacts was greater in older players and those who played the forward position, had a greater BMI, and spent more time on the ice (P = .008), whereas greater rotational acceleration was present in older players who had a greater BMI and played the forward position (P = .008). During tournament games, increased ice time predicted increased severity of head impacts (P = .03). Conclusions: This study reveals for the first time that head impacts are occurring in female youth ice hockey players, albeit at a lower rate and severity than in male youth ice hockey players, despite the lack of intentional body checking.
38
Cerruto, Emanuele, and Giuseppe Manetto. "Vibration from Electric Hand-Held Harvesters for Olives." Applied Sciences 12, no. 4 (February 9, 2022): 1768. http://dx.doi.org/10.3390/app12041768.
Full textAbstract:
Olive harvesting is the most expensive cultivation operation in areas where full mechanization is not possible due to structural conditions such as low tree density, old trees, irregular spacing, and terraced fields, which are very frequent in many small Italian farms. Under these conditions the use of hand-held vibrating harvesters is quite wide spread, because they are capable of approximately three times the productivity of workers using manual harvesting methods. Unfortunately, the use of these machines exposes the operators to hand-arm vibration risk and acceleration values are affected by several factors, including harvester kinematics, rod material and geometry, and load conditions. In this study several models of electrical portable harvesters, obtained by combining six harvester heads and four rods (one telescopic), were tested under idling and load conditions, measuring acceleration values on the rod, near the hand positions. Assuming the use of the machinery for 4 h per day, the result is a level of daily vibration exposure A(8) for the most exposed hand ranging from about 11 to 40 m/s2, much higher than the daily exposure limit value of 5 m/s2 stated by the European Directive 2002/44/EC. With the same harvester head, reduction in vibration may be achieved by using carbon fiber rods rather than aluminum ones or by increasing the rod diameter. The most significant reduction is achievable by designing harvester heads whose kinematics inherently incorporate oscillation compensation.
39
O'Connor, Kathryn L., Steven Rowson, Stefan M. Duma, and Steven P. Broglio. "Head-Impact–Measurement Devices: A Systematic Review." Journal of Athletic Training 52, no. 3 (March 1, 2017): 206–27. http://dx.doi.org/10.4085/1062-6050.52.2.05.
Full textAbstract:
Context:With an estimated 3.8 million sport- and recreation-related concussions occurring annually, targeted prevention and diagnostic methods are needed. Biomechanical analysis of head impacts may provide quantitative information that can inform both prevention and diagnostic strategies.Objective:To assess available head-impact devices and their clinical utility.Data Sources:We performed a systematic search of the electronic database PubMed for peer-reviewed publications, using the following phrases: accelerometer and concussion, head impact telemetry, head impacts and concussion and sensor, head impacts and sensor, impact sensor and concussion, linear acceleration and concussion, rotational acceleration and concussion, and xpatch concussion. In addition to the literature review, a Google search for head impact monitor and concussion monitor yielded 15 more devices.Study Selection:Included studies were performed in vivo, used commercially available devices, and focused on sport-related concussion.Data Extraction:One author reviewed the title and abstract of each study for inclusion and exclusion criteria and then reviewed each full-text article to confirm inclusion criteria. Controversial articles were reviewed by all authors to reach consensus.Data Synthesis:In total, 61 peer-reviewed articles involving 4 head-impact devices were included. Participants in boxing, football, ice hockey, soccer, or snow sports ranged in age from 6 to 24 years; 18% (n = 11) of the studies included female athletes. The Head Impact Telemetry System was the most widely used device (n = 53). Fourteen additional commercially available devices were presented.Conclusions:Measurements collected by impact monitors provided real-time data to estimate player exposure but did not have the requisite sensitivity to concussion. Proper interpretation of previously reported head-impact kinematics across age, sport, and position may inform future research and enable staff clinicians working on the sidelines to monitor athletes. However, head-impact–monitoring systems have limited clinical utility due to error rates, designs, and low specificity in predicting concussive injury.
40
Muzzy, William H., Alvah C. Bittner, and Gilbert C. Willems. "Safety Evaluation of Helmet and Other Mass Additions to the Head." Proceedings of the Human Factors Society Annual Meeting 30, no. 13 (September 1986): 1301–5. http://dx.doi.org/10.1177/154193128603001315.
Full textAbstract:
The biodynamic effects of helmet and other mass additions to the head have been of concern for more than two decades. The Naval Biodynamics Laboratory (NBDL) has performed a series of -X acceleration exposure experiments using Navy volunteers in which the dynamic response of the head was measured as a function of mass distribution variations. The kinematic response was measured for each subject with no mass addition, a helmet and weight-carrying frame, and a helmet with weights positioned on the frame symmetrically about the mid-sagittal plane. There was approximately a 30 percent addition to the head mass with these weights. Safety monitoring procedures for this investigation illustrate: (a) Computer-based methods which may apply during helmet design; and (b) experimental procedures which may be applied to assess helmet safety test and evaluation.
41
Kelley, Mirellie, Jillian Urban, Derek Jones, Alexander Powers, Christopher T. Whitlow, Joseph Maldjian, and Joel Stitzel. "Football concussion case series using biomechanical and video analysis." Neurology 91, no. 23 Supplement 1 (December 4, 2018): S2.2—S2. http://dx.doi.org/10.1212/01.wnl.0000550623.36010.20.
Full textAbstract:
Approximately 1.1–1.9 million sport-related concussions among athletes ≤18 years of age occur annually in the United States, but there is limited understanding of the biomechanics and injury mechanisms associated with concussions among lower level football athletes. Therefore, the objective of this study was to combine biomechanical head impact data with video analysis to characterize youth and HS football concussion injury mechanisms. Head impact data were collected from athletes participating on 22 youth and 6 HS football teams between 2012 and 2017. Video was recorded, and head impact data were collected during all practices and games by instrumenting players with the Head Impact Telemetry (HIT) System. For each clinically diagnosed concussion, a video abstraction form was completed, which included questions concerning the context in which the injury occurred. Linear acceleration, rotational acceleration, and impact location were used to characterize the concussive event and each injured athlete's head impact exposure on the day of the concussion. A total of 9 (5 HS and 4 youth) concussions with biomechanics and video of the event were included in this study. The mean [range] linear and rotational acceleration of the concussive impacts were 62.9 [29.3–118.4] g and 3,056.7 [1,046.8–6,954.6] rad/s2, respectively. Concussive impacts were the highest magnitude impacts for 6 players and in the top quartile of impacts for 3 players on the day of injury. Concussions occurred in both practices (N = 4) and games (N = 5). The most common injury contact surface was helmet-to-helmet (N = 5), followed by helmet-to-ground (N = 3) and helmet-to-body (N = 1). All injuries occurred during player-to-player contact scenarios, including tackling (N = 4), blocking (N = 4), and collision with other players (N = 1). The biomechanics and injury mechanisms of concussions varied among athletes in our study; however, concussive impacts were among the highest severity for each player and all concussions occurred as a result of player-to-player contact.
42
Stewart, C. E., D. S. Bauer, A. C. Kanicki, R. A. Altschuler, and W. M. King. "Intense noise exposure alters peripheral vestibular structures and physiology." Journal of Neurophysiology 123, no. 2 (February 1, 2020): 658–69. http://dx.doi.org/10.1152/jn.00642.2019.
Full textAbstract:
The otolith organs play a critical role in detecting linear acceleration and gravity to control posture and balance. Some afferents that innervate these structures can be activated by sound and are at risk for noise overstimulation. A previous report demonstrated that noise exposure can abolish vestibular short-latency evoked potential (VsEP) responses and damage calyceal terminals. However, the stimuli that were used to elicit responses were weaker than those established in previous studies and may have been insufficient to elicit VsEP responses in noise-exposed animals. The goal of this study was to determine the effect of an established noise exposure paradigm on VsEP responses using large head-jerk stimuli to determine if noise induces a stimulus threshold shift and/or if large head-jerks are capable of evoking VsEP responses in noise-exposed rats. An additional goal is to relate these measurements to the number of calyceal terminals and hair cells present in noise-exposed vs. non-noise-exposed tissue. Exposure to intense continuous noise significantly reduced VsEP responses to large stimuli and abolished VsEP responses to small stimuli. This finding confirms that while measurable VsEP responses can be elicited from noise-lesioned rat sacculi, larger head-jerk stimuli are required, suggesting a shift in the minimum stimulus necessary to evoke the VsEP. Additionally, a reduction in labeled calyx-only afferent terminals was observed without a concomitant reduction in the overall number of calyces or hair cells. This finding supports a critical role of calretinin-expressing calyceal-only afferents in the generation of a VsEP response. NEW & NOTEWORTHY This study identifies a change in the minimum stimulus necessary to evoke vestibular short-latency evoked potential (VsEP) responses after noise-induced damage to the vestibular periphery and reduced numbers of calretinin-labeled calyx-only afferent terminals in the striolar region of the sacculus. These data suggest that a single intense noise exposure may impact synaptic function in calyx-only terminals in the striolar region of the sacculus. Reduced calretinin immunolabeling may provide insight into the mechanism underlying noise-induced changes in VsEP responses.
43
Reyes, Jonathan, Biswadev Mitra, Andrew McIntosh, Patrick Clifton, Michael Makdissi, Jack V. K. Nguyen, Peter Harcourt, et al. "An Investigation of Factors Associated With Head Impact Exposure in Professional Male and Female Australian Football Players." American Journal of Sports Medicine 48, no. 6 (April 7, 2020): 1485–95. http://dx.doi.org/10.1177/0363546520912416.
Full textAbstract:
Background: Exposure to head acceleration events (HAEs) has been associated with player sex, player position, and player experience in North American football, ice hockey, and lacrosse. Little is known of these factors in professional Australian football. Video analysis allows HAE verification and characterization of important determinants of injury. Purpose: To characterize verified HAEs in the nonhelmeted contact sport of professional Australian football and investigate the association of sex, player position, and player experience with HAE frequency and magnitude. Study Design: Descriptive epidemiology study. Methods: Professional Australian football players wore a nonhelmeted accelerometer for 1 match, with data collected across 14 matches. HAEs with peak linear accelerations (PLAs) ≥30 g were verified with match video. Verified HAEs were summarized by frequency and median PLA and compared between the sexes, player position, and player experience. Characterization of match-related situations of verified HAEs was conducted, and the head impact rate per skill execution was calculated. Results: 92 male and 118 female players were recruited during the 2017 season. Male players sustained more HAEs (median, 1; IQR, 0-2) than female players (median, 0; IQR, 0-1; P = .007) during a match. The maximum PLAs incurred during a match were significantly higher in male players (median, 61.8 g; IQR, 40.5-87.1) compared with female players (median, 44.5 g; IQR, 33.6-74.8; P = .032). Neither player position nor experience was associated with HAE frequency. Of all verified HAEs, 52% (n = 110) occurred when neither team had possession of the football, and 46% (n = 98) were caused by contact from another player attempting to gain possession of the football. A subset of HAEs (n = 12; 5.7%) resulted in players seeking medical aid and/or being removed from the match (median PLA, 58.8 g; IQR, 34.0-89.0), with 2 (male) players diagnosed with concussion after direct head impacts and associated PLAs of 62 g and 75 g, respectively. In the setting of catching (marking) the football, female players exhibited twice the head impact rate (16 per 100 marking contests) than male players (8 per 100 marking contests). Conclusion: Playing situations in which players have limited control of the football are a common cause of impacts. Male players sustained a greater exposure to HAEs compared with female players. Female players, however, sustained higher exposure to HAEs than male players during certain skill executions, possibly reflecting differences in skill development. These findings can therefore inform match and skill development in the emerging professional women’s competition of Australian football.
44
Miyashita, Theresa L., and Paul A. Ullucci. "Correlation of Head Impact Exposures With Vestibulo-Ocular Assessments." Journal of Sport Rehabilitation 29, no. 3 (March 1, 2020): 310–14. http://dx.doi.org/10.1123/jsr.2017-0282.
Full textAbstract:
Context: Managing a concussion injury should involve the incorporation of a multifaceted approach, including a vision assessment. The frontoparietal circuits and subcortical nuclei are susceptible to trauma from a concussion injury, leading to dysfunction of the vestibulo-ocular system. Research investigating the effect of cumulative subconcussive impacts on neurological function is still in its infancy, but repetitive head impacts may result in vestibular system dysfunction. This dysfunction could create visual deficits, predisposing the individual to further head trauma. Objective: The purpose of this study was to investigate the cumulative effect of subconcussive impacts on minimum perception time, static visual acuity, gaze stability, and dynamic visual acuity scores. Design: Prospective cohort. Setting: Division I university. Patients: Thirty-three Division I men’s lacrosse players (age = 19.52 [1.20] y). Intervention: Competitive lacrosse season. Main Outcome Measures: At the beginning and end of the season, the players completed a vestibulo-ocular reflex assessment, using the InVision™ system by Neurocom® to assess perception, static acuity, gaze stability, and dynamic visual acuity. Score differentials were correlated with the head impact exposure data collected via instrumented helmets. Results: A significant correlation was found between change in perception scores and total number of head impacts (r = .54), and between changes in dynamic visual acuity loss scores on the rightside and maximum rotational acceleration (r = .36). No statistical differences were found between preseason and postseason vestibulo-ocular reflex variables. Conclusions: Cumulative subconcussive impacts may negatively affect vestibulo-ocular reflex scores, resulting in decreased visual performance. This decrease in vestibulo-ocular function may place the athlete at risk of sustaining additional head impacts or other injuries.
45
Besch, E. L., P. M. Werchan, J. F. Wiegman, T. E. Nesthus, and A. R. Shahed. "Effect of hypoxia and hyperoxia on human +Gz duration tolerance." Journal of Applied Physiology 76, no. 4 (April 1, 1994): 1693–700. http://dx.doi.org/10.1152/jappl.1994.76.4.1693.
Full textAbstract:
To determine the effects of varying inspired O2 on positive radial acceleration (+Gz; i.e., head-to-foot inertial load) duration tolerance, seven men were exposed to the +4.5- to +7.0-Gz simulated aerial combat maneuver (SACM) by use of the Armstrong Laboratory (Brooks Air Force Base) centrifuge. Exposures were repeated on different days while subjects breathed gas mixtures of fractional concentration of O2 in inspired air (FIO2) between 0.12 and 0.6. SACM duration tolerance was positively related to inspired O2 of FIO2 between 0.12 and 0.2 but was unchanged at FIO2 between 0.2 and 0.6. SACM exposure decreased arterial O2 saturation and increased heart rates; SACM-induced changes were additive to FIO2 effects. The positive relationship between blood lactate and SACM duration tolerance at all FIO2 indicated an anaerobic component. It is concluded that SACM duration tolerance is limited by reduced FIO2 but not enhanced by hyperoxia. Thus the aerobic component of +4.5- to +7.0-Gz SACM duration tolerance is much greater than previously believed.
46
Jang, Ikbeom, Il Yong Chun, Jared R. Brosch, Sumra Bari, Yukai Zou, Brian R. Cummiskey, Taylor A. Lee, et al. "Every hit matters: White matter diffusivity changes in high school football athletes are correlated with repetitive head acceleration event exposure." NeuroImage: Clinical 24 (2019): 101930. http://dx.doi.org/10.1016/j.nicl.2019.101930.
Full text
47
Ivnev, Alexander Andreevich, Vladimir Anatoljevich Zhukov, Yuriy Evgenievich Khryashchyev, and Alexander Ivanovich Yamanin. "Thermal tension of cylinder covers of transport diesel engines converted to marine diesels." Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2021, no. 2 (May 31, 2021): 55–64. http://dx.doi.org/10.24143/2073-1574-2021-2-55-64.
Full textAbstract:
The article describes the characteristics of thermal loading of the cylinder covers of transport diesel engines during their conversion to marine diesels. The engines of the CHN14/14 type produced by the Yaroslavl Motor Plant are proposed as promising for use in marine power plants. A special feature of the engine design is the individual four-valve cylinder heads, which have a complex geometric shape. The conversion of automobile engines, the cylinder heads of which were made of aluminum alloys, to marine ones is accompanied by an increase in the degree of their acceleration. The cylinder heads in operation experience significant thermal and mechanical loads, which causes the need for increased requirements for the materials of the cylinder heads. The rational choice of the cylinder head material is one of the most important tasks to be solved when upgrading and boosting engines. Experience in the operation of marine diesel engines shows that in order to ensure the required reliability under prolonged exposure to elevated temperatures due to forcing, it is necessary to choose cast iron as a structural material. A three-dimensional model of the cylinder head is developed. When performing the calculations, the boundary conditions are justified, taking into account the local nature of the distribution of thermal and mechanical effects on the diesel cylinder head. As a result of numerical modeling, the stress-strain states of cylinder heads made of high-strength cast iron, ductile iron and cast iron with vermicular graphite are determined and analyzed. There has been proved the preference for using cast irons with vermicular graphite, which have satisfactory casting and physical and mechanical properties. The advantages of using cast iron with vermicular graphite include a decrease in the temperature of the cylinder head in the area of the inter-valve bridge. The possibility of increasing the engine power from 330 to 560 kW when replacing aluminum alloys with cast iron with vermicular graphite for the manufacture of cylinder heads is proved.
48
Gallagher, Maria, Reno Choi, and Elisa Raffaella Ferrè. "Multisensory Interactions in Virtual Reality: Optic Flow Reduces Vestibular Sensitivity, but Only for Congruent Planes of Motion." Multisensory Research 33, no. 6 (June 17, 2020): 625–44. http://dx.doi.org/10.1163/22134808-20201487.
Full textAbstract:
Abstract During exposure to Virtual Reality (VR) a sensory conflict may be present, whereby the visual system signals that the user is moving in a certain direction with a certain acceleration, while the vestibular system signals that the user is stationary. In order to reduce this conflict, the brain may down-weight vestibular signals, which may in turn affect vestibular contributions to self-motion perception. Here we investigated whether vestibular perceptual sensitivity is affected by VR exposure. Participants’ ability to detect artificial vestibular inputs was measured during optic flow or random motion stimuli on a VR head-mounted display. Sensitivity to vestibular signals was significantly reduced when optic flow stimuli were presented, but importantly this was only the case when both visual and vestibular cues conveyed information on the same plane of self-motion. Our results suggest that the brain dynamically adjusts the weight given to incoming sensory cues for self-motion in VR; however this is dependent on the congruency of visual and vestibular cues.
49
Caswell, Shane V., Andrew E. Lincoln, Hannah Stone, Patricia Kelshaw, Margot Putukian, Lisa Hepburn, Michael Higgins, and Nelson Cortes. "Characterizing Verified Head Impacts in High School Girls’ Lacrosse." American Journal of Sports Medicine 45, no. 14 (September 18, 2017): 3374–81. http://dx.doi.org/10.1177/0363546517724754.
Full textAbstract:
Background: Girls’ high school lacrosse players have higher rates of head and facial injuries than boys. Research indicates that these injuries are caused by stick, player, and ball contacts. Yet, no studies have characterized head impacts in girls’ high school lacrosse. Purpose: To characterize girls’ high school lacrosse game-related impacts by frequency, magnitude, mechanism, player position, and game situation. Study Design: Descriptive epidemiology study. Methods: Thirty-five female participants (mean age, 16.2 ± 1.2 years; mean height, 1.66 ± 0.05 m; mean weight, 61.2 ± 6.4 kg) volunteered during 28 games in the 2014 and 2015 lacrosse seasons. Participants wore impact sensors affixed to the right mastoid process before each game. All game-related impacts recorded by the sensors were verified using game video. Data were summarized for all verified impacts in terms of frequency, peak linear acceleration (PLA), and peak rotational acceleration (PRA). Descriptive statistics and impact rates were calculated. Results: Fifty-eight verified game-related impacts ≥20 g were recorded (median PLA, 33.8 g; median PRA, 6151.1 rad/s2) during 467 player-games. The impact rate for all game-related verified impacts was 0.12 per athlete-exposure (AE) (95% CI, 0.09-0.16), equivalent to 2.1 impacts per team game, indicating that each athlete suffered fewer than 2 head impacts per season ≥20 g. Of these impacts, 28 (48.3%) were confirmed to directly strike the head, corresponding with an impact rate of 0.05 per AE (95% CI, 0.00-0.10). Overall, midfielders (n = 28, 48.3%) sustained the most impacts, followed by defenders (n = 12, 20.7%), attackers (n = 11, 19.0%), and goalies (n = 7, 12.1%). Goalies demonstrated the highest median PLA and PRA (38.8 g and 8535.0 rad/s2, respectively). The most common impact mechanisms were contact with a stick (n = 25, 43.1%) and a player (n = 17, 29.3%), followed by the ball (n = 7, 12.1%) and the ground (n = 7, 12.1%). One hundred percent of ball impacts occurred to goalies. Most impacts occurred to field players within the attack area of the field (n = 32, 55.2%) or the midfield (n = 18, 31.0%). Most (95%) impacts did not result in a penalty. Conclusion: The incidence of verified head impacts in girls’ high school lacrosse was quite low. Ball to head impacts were associated with the highest impact magnitudes. While stick and body contacts are illegal in girls’ high school lacrosse, rarely did such impacts to the head result in a penalty. The verification of impact mechanisms using video review is critical to collect impact sensor data.
50
Goggins, Katie A., Elizabeth A. Kelly, Taryn J. Thompson, and Tammy R. Eger. "Examining the Impact of Rotated Neck and Trunk Postures on Vertical Seat-to-Head Vibration Transmissibility and Self-Reported Discomfort." Vibration 5, no. 2 (May 16, 2022): 306–25. http://dx.doi.org/10.3390/vibration5020018.
Full textAbstract:
Adopting non-neutral sitting postures while exposed to whole-body vibration (WBV) can put heavy equipment operators at an increased risk for lower back pain and may cause damage to the spinal tissue. A laboratory experiment involving 11 participants (5 females, 6 males) completing four 45-min test sessions incorporating different seated conditions (vibration versus no vibration, and rotation versus no rotation) was used to assess seat-to-head transmissibility (STHT) and self-reported discomfort while in four rotated neck and trunk postures. The vibration exposure profile was a constant vertical sinusoidal signal with a frequency of 3 Hz and 0.7 m/s2 acceleration. Vibration measured at the head was greater than at the seat under all conditions, with a statistically significant effect of time (F1,10 = 101.73, p < 0.001, Eta2 = 0.910) and posture (F3,8 = 5.64, p = 0.023, Eta2 = 0.679). Mean self-reported discomfort ratings revealed increased participant discomfort in rotated neck and trunk positions in both vibration and non-vibration conditions. Increasing time also had a significant (F(1,10) = 15.53, p = 0.003) impact on higher rates of participant discomfort. Overall, it was found that increasing the degree of rotated neck and trunk position from neutral amplified the STHT and self-reported discomfort.