In Vivo Study of Head Impacts in Football

Schnebel, Brock; Gwin, Joseph T.; Anderson, Scott; Gatlin, Ron

doi:10.1227/01.neu.0000249286.92255.7f

Cited by 179 publications

(97 citation statements)

References 17 publications

(29 reference statements)

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“…Recently, the development of HITS, which collects impact information from the acceleration sensor attached inside the helmet and the sideline response system, which transmits the data, has made it possible to collect collision data from players on actual fields [9][10][11][12][13][19][20][21][22][23][24][25][26][27][28] . However, HITS only measures LA, and RA had to be estimated 28) .…”

Section: Discussionmentioning

confidence: 99%

“…Crisco reported that a university player experienced 6.3 and 14.3 impacts during a practice session and a game, respectively 10) . Also, Schnebel reported that the number of impacts per player during a training session was approximately 13 22) . These findings and our results were similar in terms of the number of collisions during the games.…”

Section: Discussionmentioning

confidence: 99%

“…These findings and our results were similar in terms of the number of collisions during the games. While a single game is on the results 22,24) . However, unlike the finding that the ratio of total number of impacts for backs to linemen was 1:3 10,22) , this study showed that the ratio is closer to 1:1.3.…”

Section: Discussionmentioning

confidence: 99%

“…While a single game is on the results 22,24) . However, unlike the finding that the ratio of total number of impacts for backs to linemen was 1:3 10,22) , this study showed that the ratio is closer to 1:1.3. In this study, the numbers of participating backs and linemen were different (backs: 14, linemen: 9), so we took the average per person and still obtained a 1:2 (262:516) ratio.…”

Section: Discussionmentioning

confidence: 99%

“…In the 2000s, many researchers started to use a headimpact telemetry system (HITS, Simbex, Lebanon NH) equipped with an acceleration sensor installed inside a Riddell (Elyria, OH) helmet to collect real-time headacceleration data during head collisions between American football players [9][10][11][12][13][19][20][21][22][23][24][25][26][27][28] . The data collected by HITS is transmitted to a PC application in real time via a sideline response system (Riddell, Chicago, IL).…”

Section: Introductionmentioning

confidence: 99%

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Impact on the head during collisions between university American football players - focusing on the number of head impacts and linear head acceleration -

Fukuda

Koike

Miyakawa

et al. 2017

JPFSM

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The aim of this study is to understand the head impact during actual collisions between American football players from Japanese universities. The subjects of this study were 23 players who belonged to T university in the Kantoh Collegiate American Football Association Division 2. We used a Vector Mouthguard (i1 Biometrics Inc.) equipped with 6 degrees of freedom (DOF) to measure the head linear acceleration (LA) and rotational acceleration (RA) as well as the head injury criterion (HIC), impact location, and number of impacts during collisions. The average number of collisions per player during a practice and during a game was 14.3 and 15.7, respectively. In terms of positions, the ratio (1:1.3) of total number of impacts for backs to linemen in Japan is lower than that (1:3) in the USA. Both during the games and practices, the range of 10 g < X ≤ 15 g in the average peak LA values was the most frequent, and the distributions were largely skewed toward low values (p < 0.05). The medians during the games and practices were 16.77 g and 15.87 g, respectively. The number of collisions during practices in Japan was significantly higher than that in the USA. Particularly, linemen undergo more head collisions than those of backs. Another common factor is that the impact of head collision during a game is significantly higher than that during a practice. However, data on Japanese university players is limited, and further data collection should be done before determining an accurate estimate of the practical concussion risk threshold.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Impact on the head during collisions between university American football players - focusing on the number of head impacts and linear head acceleration -

Fukuda

Koike

Miyakawa

et al. 2017

JPFSM

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Association of Football Subconcussive Head Impacts With Ocular Near Point of Convergence

et al. 2016

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IMPORTANCE An increased understanding of the relationship between subconcussive head impacts and near point of convergence (NPC) ocular-motor function may be useful in delineating traumatic brain injury.OBJECTIVE To investigate whether repetitive subconcussive head impacts during preseason football practice cause changes in NPC. DESIGN, SETTING, AND PARTICIPANTSThis prospective, observational study of 29 National Collegiate Athletic Association Division I football players included baseline and preseason practices (1 noncontact and 4 contact), and postseason follow-up and outcome measures were obtained for each time. An accelerometer-embedded mouthguard measured head impact kinematics. Based on the sum of head impacts from all 5 practices, players were categorized into lower (n = 7) or higher (n = 22) impact groups.EXPOSURES Players participated in regular practices, and all head impacts greater than 10g from the 5 practices were recorded using the i1Biometerics Vector mouthguard (i1 Biometrics Inc). MAIN OUTCOMES AND MEASURES Near point of convergence measures and symptom scores.RESULTS A total of 1193 head impacts were recorded from 5 training camp practices in the 29 collegiate football players; 22 were categorized into the higher-impact group and 7 into the lower-impact group. There were significant differences in head impact kinematics between lower-and higher-impact groups (number of impacts, 6 vs 41 [lower impact minus higher impact = 35; 95% CI, 21-51; P < .001]; linear acceleration, 99g vs 1112g [lower impact minus higher impact= 1013; 95% CI, 621 -1578; P < .001]; angular acceleration, 7589 radian/s 2 vs 65 016 radian/s 2 [lower impact minus higher impact= 57 427; 95% CI , 31 123-80 498; P < .001], respectively). The trajectory and cumulative burden of subconcussive impacts on NPC differed by group (F for group × linear trend 1, 238 = 12.14, P < .001 and F for group × quadratic trend 1, 238 = 12.97, P < .001). In the higher-impact group, there was a linear increase in NPC over time (B for linear trend, unstandardized coefficient [SE]: 0.76 [0.12], P < .001) that plateaued and resolved by postseason follow-up (B for quadratic trend [SE]: −0.06 [0.008], P < .001). In the lower-impact group, there was no change in NPC over time. Group differences were first observed after the first contact practice and remained until the final full-gear practice. No group differences were observed postseason follow-up. There were no differences in symptom scores between groups over time. CONCLUSIONS AND RELEVANCEAlthough asymptomatic, these data suggest that repetitive subconcussive head impacts were associated with changes in NPC. The increase in NPC highlights the vulnerability and slow recovery of the ocular-motor system following subconcussive head impacts. Changes in NPC may become a useful clinical tool in deciphering brain injury severity.

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Neuro-Ophthalmologic Response to Repetitive Subconcussive Head Impacts

et al. 2020

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IMPORTANCE Subconcussive head impacts have emerged as a complex public health concern. The oculomotor system is sensitive to brain trauma; however, neuro-ophthalmologic response to subconcussive head impacts remains unclear.OBJECTIVE To examine whether subconcussive head impacts cause impairments in neuro-ophthalmologic function as measured by the King-Devick test (KDT) and oculomotor function as measured by the near point of convergence. DESIGN, SETTING, AND PARTICIPANTSIn this randomized clinical trial, adult soccer players were randomized into either a heading group or kicking (control) group. The heading group executed 10 headers with soccer balls projected at a speed of 25 mph. The kicking-control group followed the same protocol but with 10 kicks. Peak linear and rotational head accelerations were assessed with a triaxial accelerometer. The KDT speed and error and near point of convergence were assessed at baseline (preheading or prekicking) and at 0, 2, and 24 hours after heading or kicking.EXPOSURES Ten soccer-ball headings or kicks. MAIN OUTCOMES AND MEASURESThe primary outcome was the group-by-time interaction of KDT speed at 0 hours after heading or kicking. The secondary outcomes included KDT speed at 2 hours and 24 hours after heading or kicking, KDT error, and near point of convergence.RESULTS A total of 78 individuals enrolled (heading group, n = 40; kicking-control group, n = 38). Eleven individuals (heading group: 4 women; mean [SD] age, 22.5 [1.0] years; kicking-control group, 3 women and 4 men; mean [SD] age, 20.9 [1.1] years) voluntarily withdrew from the study. Data from 67 participants with a mean (SD) age of 20.6 (1.7) years were eligible for analysis (heading, n = 36; kicking-control, n = 31). Mean (SD) peak linear accelerations and peak rotational accelerations per impact for the heading group were 33.2 (6.8) g and 3.6 (1.4) krad/s 2 , respectively. Conversely, soccer kicking did not induce a detectable level of head acceleration. Both groups showed improvements in KDT speed (heading group: 0

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In Vivo Study of Head Impacts in Football

Cited by 179 publications

References 17 publications

Impact on the head during collisions between university American football players - focusing on the number of head impacts and linear head acceleration -

Impact on the head during collisions between university American football players - focusing on the number of head impacts and linear head acceleration -

Association of Football Subconcussive Head Impacts With Ocular Near Point of Convergence

Neuro-Ophthalmologic Response to Repetitive Subconcussive Head Impacts

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