Human Impact Tolerance and

Transcription

1 Human Impact Tolerance and The STAR Helmet Rating System Stefan M. Duma, Steven Rowson, Joel Stitzel, Ray Daniel, Bryan Cobb, Tyler Young, Brock Strom, Craig McNally, Anna MacAlister, Gunnar Brolinson, Mike Goforth, Mark Rogers, John Shifflett, Alex Powers, Chris Whitlow, Jill Urban, Joseph Maldjian, Elizabeth Davenport Massachusetts Secondary Schools Athletic Directors Association March 20, 2013

2 VT WFU Brain Injury Research Team Virginia Tech Duma Rowson Daniel Cobb VT-VCOM / Sports Med MacAlister Young Strom McNally Brolinson Goforth Rogers Shifflett Wake Forest Stitzel Powers Whitlow Maldjian Urban Davenport

3 Financial Disclaimer No financial interest in SIMBEX, HITS, or any other helmet related sensor or product No financial interest in Riddell, or any helmet manufacturer No helmet expert witness consulting Speaking fees donated to buy new helmets for youth teams in south-west Virginia.

4 Funding Sources National Institutes of Health National Inst. Of Child Health & Human Development, R01HD Department of Transportation National Highway Traffic Safety Administration Department of Defense US Medical Research and Material Command Toyota Motor Corporation Toyota Central Research and Development Labs

5 Presentation Outline Part 1: Injury Biomechanics Background Reducing injuries in auto-safety, sports, military Part 2: STAR Helmet Rating System Fundamental Questions Review of exposure and risk analysis Part 3: Youth Football Data

6 Duma Research Group Projects Helmet, Brain Toy Projectiles Toy Sword (Nerf) Toy Helicopter Eye Blast Military DOD Projects Child Dummy Thorax, Rib Fractures Facial Fracture Automobile DOT Projects Pregnant Neck Brain Blast

7 VT-WFU Research Experience Head: FOCUS Headform Eye Modeling/Experimental Skull Fracture Restraint Evaluation Helicopter Airbags Upper Limb Injuries Neck Head Supported Mass Crash Pulse and Parachuting Chest Lung Tissue Rib Fractures Sponsors: Army Research Office, US Army Aeromedical Research Laboratory, US Army Medical Research and Materiel Command

8 Pregnant Occupant Research

9 Toy Design

10 Toy Design

11 My Future Career Brock Duma Age 8

12 Automobile Analogy

13 Federal Motor Vehicle Safety Standards (FMVSS) are pass / fail FMVSS 208 Frontal Impact FMVSS 214 Side Impact Fixed Barrier 30 mph 33.5 mph 20 mph MDB

14

15 New Car Assessment Program(NCAP) NHTSA rates safety on 5 star scale 20 mph Fixed Barrier 35 mph Injury risk to the head, neck, chest, and femur frontal and side tests (rollover is ratio calculation) 38.5 mph Total Risk = 1 (1 Risk head )*(1 Risk neck ) *(1 Risk chest )*(1 Risk femur ) Overall risk = 5/12 * frontal + 4/12 * side + 3/12 * rollover

16 New Car Assessment Program (NCAP) NHTSA rates safety on 5 star scale Injury risk to the head, neck, chest, and Fixed Barrier femur are considered for frontal and side A star rating is assigned based the overall tests (rollover is ratio calculation) 20 mph risk of serious injury from all tests combined 35 mph A total injury risk for each testing configuration is computed Stars Each 2 overall injury risk 1 is weighted based on exposure and summed to compute 0% 10% 15% 20% overall risk40% 100% Overall Risk 38.5 mph Total Risk = 1 (1 Risk head )*(1 Risk neck ) *(1 Risk chest )*(1 Risk femur ) Overall risk = 5/12 * frontal + 4/12 * side + 3/12 * rollover

17 ~1968 FMVSS 208 (pass/fail) ~1978 NCAP frontal (stars) 44,525 ~1997 NCAP side 33,808

18 Active Research in all Current and Future Body Regions Head injury (HIC) Neck injury (Nij) Chest compression Abdomen Femur loads Pelvis Tibia Ankle complex We do not know 100% about everything, but know enough to make safety advances

19 Active Research in all Current and Future Body Regions Head injury (HIC) Neck injury (Nij) Chest compression Femur loads Accelerations Loads Abdomen Pelvis Injury Risk Tibia Ankle complex We do not know 100% about everything, but know enough to make safety advances

20 Presentation Outline Part 1: Injury Biomechanics Background Reducing injuries in auto-safety, sports, military Part 2: STAR Helmet Rating System Fundamental Questions Review of exposure and risk analysis Part 3: Youth Football Data

21 Concussion Incidence Minimization Rule Changes 3 Strategies: Reduce exposure to head impact Rule changes Proper technique Most Eff ti Proper Technique Effective Reduce concussion risk for remaining head impacts Improve helmet design Better Equipment + Fewest Concussions

22 Age Definitions Generalized ed Football Values: League e Rules May Vary Age IOM Youth Definition 21 Helmet Type: Youth Football Adult Football Level of Play: Elementary Middle High School School School Football Football Football College Football 21 NFL

23 Fundamental Questions:

24 Is head acceleration correlated with concussion risk?

25 Experimental Concussion Research Cadaver Data Animal Data NFL Data Volunteer Data

26 Experimental Concussion Research Cadaver Data Animal Data NFL Data Volunteer Data 1954 Ford funds WSU 1961 Gurdjian, Lissner origin of WSTC 1966 Gadd: GSI or SI (General Motors) 1971 Versace: HIC (Ford) 1997 Mertz: scaling 2007 Hardy: brain strain and pressure

27 Cadaver Data Hardy: In Situ Brain Strain Football helmet impacts Linear and Rotational Accelerations Neutral Density Targets As accelerations increase, brain pressure and motion increase 5 mm Hardy et al (2007)

28 Experimental Concussion Research Cadaver Data Animal Data NFL Data Volunteer Data 1954 Ford funds WSU 1961 Gurdjian, Lissner origin of WSTC 1966 Gadd: GSI or SI (General Motors) 1971 Versace: HIC (Ford) 1997 Mertz: scaling 2007 Hardy: brain strain and pressure As linear acceleration increases, risk of injury increases. As linear and rotational acceleration increase, brain pressure and motion increase

29 Experimental Concussion Research Cadaver Data Animal Data NFL Data Volunteer Data 1954 Ford funds WSU 1961 Gurdjian, Lissner origin of WSTC Over 200 Primate tests performed in six sets from Gadd: GSI or SI (General Motors) 1966 Ommaya, Hirsch first primate tests 1971 Versace: HIC (Ford) 1997 Mertz: scaling 2007 Hardy: brain strain and pressure As linear acceleration increases, risk of injury increases. As linear and rotational acceleration increase, brain pressure and motion increase

30 Animal Data Summary of Six Sets of Primate Tests 1966 Ommaya, Hirsch Rotation alone could not cause concussion, needed impact 1980 Ono JARI Human Tolerance Curve Skull fracture and concussion curves 1971 Ommaya, Hirsch Rotation accounts for ½ of brain injury, linear accounts for the other half 1971 Gennarelli, Ommaya, Thibault linear and rotational acceleration relating to concussion 1972 Gennarelli, Thibault, Ommaya Rotation related to diffuse brain injury 1981 Gennarelli Directional dependence of brain injury 1982 Gennarelli, Thibault DAI and coma 1982 Gennarelli, Thibault Sub-dural hematoma 1985 Thibault, Gennarelli Rotation and diffuse brain injury 1971 Unterharnscheidt Both linear and rotational acceleration are important for brain injury 1983 Hodgson Higher linear and rotational acceleration associated with increase brain injury

31 Experimental Concussion Research Cadaver Data Animal Data NFL Data Volunteer Data 1954 Ford funds WSU 1961 Gurdjian, Lissner origin of WSTC Over 200 Primate tests performed in six sets from Gadd: GSI or SI (General Motors) 1971 Versace: HIC (Ford) 1997 Mertz: scaling 2007 Hardy: brain strain and pressure As linear acceleration increases, risk of injury increases Ommaya, Hirsch first primate tests More recent analysis: 1985 Ommaya:4500r/s2 concussion 1992 Margulies,Thibault DAI at 16,000 r/s Arbogast, and Margulies: properties 2003 Gennarelli: concussion values 2009 Davidsson: DAI As linear and rotational acceleration increase, brain pressure and motion increase

32 Animal Data Ommaya: Tolerance to Concussion Scaled from Primates 10, Pulse Duration Time in ms Velocity (rad d/s) 1, Rhesus Monkey Rotational 100 Man Chimpanzee 10 1,000 10, , ,000, Rotational Acceleration (rad/s 2 ) (Ommaya, 1985)

33 Animal Data Gennarelli: Rotational Acceleration and Concussion Ro otational Acc celeration (ra ad/s 2 ) Pure Sagittal Pure Lateral 30 Oblique None Mild Concussion Classical Concussion Severe Concussion Mild DAI Moderate DAI Severe DAI (Gennarelli, 1985; Gennarelli, 2003)

34 Animal Data Rotational Acceleration Comparison Concussion DAI NFL Volunteer DAI

35 Experimental Concussion Research Cadaver Data Animal Data NFL Data Volunteer Data 1954 Ford funds WSU 1961 Gurdjian, Lissner origin of WSTC Over 200 Primate tests performed in six sets from Gadd: GSI or SI (General Motors) 1971 Versace: HIC (Ford) 1997 Mertz: scaling 2007 Hardy: brain strain and pressure As linear acceleration increases, risk of injury increases. As linear and rotational acceleration increase, brain pressure and motion increase 1966 Ommaya, Hirsch first primate tests More recent analysis: 1985 Ommaya:4500r/s2 concussion 1992 Margulies,Thibault DAI at 16,000 r/s Arbogast, and Margulies: properties 2003 Gennarelli: concussion values 2009 Davidsson: DAI As linear and rotational accelerations increase, brain injury in primates increases

36 Experimental Concussion Research Cadaver Data Animal Data NFL Data Volunteer Data 1954 Ford funds WSU 1961 Gurdjian, Lissner origin of WSTC Over 200 Primate tests performed in six sets from Gadd: GSI or SI (General Motors) 1971 Versace: HIC (Ford) 1997 Mertz: scaling 2007 Hardy: brain strain and pressure As linear acceleration increases, risk of injury increases. As linear and rotational acceleration increase, brain pressure and motion increase 1966 Ommaya, Hirsch first primate tests More recent analysis: 1985 Ommaya:4500r/s2 concussion 1992 Margulies,Thibault DAI at 16,000 r/s Arbogast, and Margulies: properties 2003 Gennarelli: concussion values 2009 Davidsson: DAI As linear and rotational accelerations increase, brain injury in primates increases Mid-90s to present: extensive research utilizing dummy reconstructions and other evaluations 2003: Pellman, Viano HIII reconstructions 2003: King, analysis of tests with model

37 NFL Video Reconstructions (Pellman, 2003)

38 NFL Data King: Linear and Rotational Acceleration 53 NFL Cases: 22 injury and 31 Non-injury Injury Prob bability P < Injury Prob bability P < Linear Acceleration (m/s 2 ) Angular Acceleration (rad/s 2 ) Pellman: Linear and Rotational Acceleration 58 NFL Cases: 25 injury and 33 Non-injury (King, 2003) (Pellman, 2003)

39 Experimental Concussion Research Cadaver Data Animal Data NFL Data Volunteer Data 1954 Ford funds WSU 1961 Gurdjian, Lissner origin of WSTC Over 200 Primate tests performed in six sets from Gadd: GSI or SI (General Motors) 1971 Versace: HIC (Ford) 1997 Mertz: scaling 2007 Hardy: brain strain and pressure As linear acceleration increases, risk of injury increases. As linear and rotational acceleration increase, brain pressure and motion increase 1966 Ommaya, Hirsch first primate tests More recent analysis: 1985 Ommaya:4500r/s2 concussion 1992 Margulies,Thibault DAI at 16,000 r/s Arbogast, and Margulies: properties 2003 Gennarelli: concussion values 2009 Davidsson: DAI As linear and rotational accelerations increase, brain injury in primates increases Mid-90s to present: extensive research utilizing dummy reconstructions and other evaluations 2003: Pellman, Viano HIII reconstructions 2003: King, analysis of tests with model Linear and rotational ti accelerations are significantly correlated to concussion risk

40 Experimental Concussion Research Cadaver Data Animal Data NFL Data Volunteer Data 1954 Ford funds WSU 1961 Gurdjian, Lissner origin of WSTC Over 200 Primate tests performed in six sets from Gadd: GSI or SI (General Motors) 1971 Versace: HIC (Ford) 1997 Mertz: scaling 2007 Hardy: brain strain and pressure As linear acceleration increases, risk of injury increases Ommaya, Hirsch first primate tests More recent analysis: 1985 Ommaya:4500r/s2 concussion 1992 Margulies,Thibault DAI at 16,000 r/s Arbogast, and Margulies: properties 2003 Gennarelli: concussion values 2009 Davidsson: DAI Mid-90s to present: extensive research utilizing dummy reconstructions and other evaluations 2003: Pellman, Viano HIII reconstructions 2003: King, analysis of tests with model 2003 Present, instrumented high school and college football players As linear and rotational acceleration increase, brain pressure and motion increase As linear and rotational accelerations increase, brain injury in primates increases Linear and rotational ti accelerations are significantly correlated to concussion risk

41 Helmet Instrumentation Two parallel systems during past 10 years HIT System 6DOF Device (VT) Volunteer Data 6 Accelerometers mounted normal to the skull 3 Linear and Resultant Rotational Accelerations ~$1,000/helmet Validated by NFL, others 12 Accelerometers mounted tangential ti 3 Linear and 3 Rotational Accelerations (6DOF) ~$10,000/helmet000/helmet Validates HIT System

42 Volunteer Data Cumulative HITS Data Collection Total Numb ber of Impa acts Collected at Virginia Tech 200, , , , , ,000 80,000 60,000 40,000 20, ,000+ impacts recorded at Virginia Tech 2,000,000+ impacts recorded at all institutions Virginia Tech Virginia Tech Virginia Tech Virginia Tech Virginia Tech Virginia Tech Virginia Tech Virginia Tech Virginia Tech Virginia Tech North Carolina North Carolina North Carolina North Carolina North Carolina North Carolina North Carolina North Carolina North Carolina Teams Using the HIT System Oklahoma Oklahoma Dartmouth Arizona State 1 High School 5 High Schools Oklahoma Dartmouth Arizona State Indiana Illinois 5 High Schools Oklahoma Dartmouth Brown Indiana Minnesota 2 High Schools Oklahoma Dartmouth Brown Indiana 3 High Schools Oklahoma Dartmouth Brown Indiana 4 High Schools Oklahoma Dartmouth Brown Indiana Wake Forest 4 High Schools Oklahoma Dartmouth Brown Indiana Wake Forest 4 High Schools Oklahoma Dartmouth Brown Indiana 4 High Schools 1 Youth Team 5 Youth Teams

43 Head Acceleration Data Collection Up to 64 Virginia Tech players instrumented for each season Data collected for every game and practice - instrumented helmet

44 Wireless Coverage Base Unit 120 Impact Onboard Memory

45 Example MTBI Event

46 Example MTBI Event Peak G = 136 G Clinically diagnosed concussion

47 Linear Acceleration Comparison NFL Data Volunteer Data 25 Concussions 105 Concussions 98 +/- 27 g 105 +/- 27 g Two very different methodologies, resulting concussion values nearly identical Strong evidence in determination of accelerations involving concussions (Pellman, 2003; Broglio, 2010; Guskiewicz 2007, 2011; Mihalik, 2007; Rowson, 2011)

48 Rotational Acceleration Comparison Concussion DAI NFL Volunteer DAI

49 Experimental Concussion Research Cadaver Data Animal Data NFL Data Volunteer Data 1954 Ford funds WSU 1961 Gurdjian, Lissner origin of WSTC Over 200 Primate tests performed in six sets from Gadd: GSI or SI (General Motors) 1971 Versace: HIC (Ford) 1997 Mertz: scaling 2007 Hardy: brain strain and pressure As linear acceleration increases, risk of injury increases Ommaya, Hirsch first primate tests More recent analysis: 1985 Ommaya:4500r/s2 concussion 1992 Margulies,Thibault DAI at 16,000 r/s Arbogast, and Margulies: properties 2003 Gennarelli: concussion values 2009 Davidsson: DAI Mid-90s to present: extensive research utilizing dummy reconstructions and other evaluations 2003: Pellman, Viano HIII reconstructions 2003: King, analysis of tests with model 2003 Present, instrumented high school and college football players As linear and rotational acceleration increase, brain pressure and motion increase As linear and rotational accelerations increase, brain injury in primates increases Linear and rotational ti accelerations are significantly correlated to concussion risk Linear and rotational ti accelerations are significantly correlated to concussion risk

50 Is head acceleration correlated with concussion risk? Yes, as shown by the evidence.

51 Concussions and Head Impact NFL Data 25 Concussions Volunteer Data 105 Concussions 100% from head impact 100% from head impact Evidence clearly illustrates concussions are caused by head impacts Non-head impact related symptoms are very rare and not the primary problem (Pellman, 2003; Broglio, 2010; Guskiewicz 2007, 2011; Mihalik, 2007; Rowson, 2011)

52 Do helmets differ in their ability to reduce head acceleration?

53 NOCSAE Drop Test Linear acceleration only NOCSAE headform Various drop heights Various directions

54 Helmet Comparison: Top Impact from 60 inch Drop Height VS Adams A2000 Riddell Severity Index 200 Peak Acceleration (g) NOCSAE Pass / Fail Threshold Adams A2000 Riddell Adams A2000 Riddell 360

55 Linear Impactor Style Test HIII Head and Neck Linear and Rotational Accelerations Various impact speed and directions

56 NFL Extensive Helmet Testing (Viano, 2006): 10 newer helmets compare against the standard VSR-4 Found 6%- 14% reduction in linear acceleration Found 10% - 23% reduction in rotational acceleration (Viano, 2011a): 2010 helmets compared to those in the 1970s Linear and rotational accelerations dramatically reduced, variation by helmet type (Viano, 2011b): Modern helmet performance 4 of 17 showed significant improvement in reduction of head accelerations

57 STAR Rating System for Football Helmets STAR: Summation of Tests for the Analysis of Risk 4 6 STAR = E ( h ) R ( a ) L= 1 H= 1 Combines true impact exposure with an unbiased risk analysis using real world biomechanical data to assess helmet safety for consumers. (Rowson and Duma, 2011)

58 STAR Rating System for Football Helmets STAR: Summation of Tests for the Analysis of Risk 4 6 STAR = E ( h ) R ( a ) L= 1 H= 1 L: Impact Location L: Impact Location Helmet location, of which, 4 will be tested: front, rear, side, and top

59 Helmet Testing Protocol Test 4 impact locations: Front Rear Side Top Test t5i impact energies: 12in, 24i in, 36i in, 48i in, 60i in

60 Impact Location Analysis used to determine the weighting of each impact location to better represent what athletes experience Subset of in situ head acceleration collected at Virginia Tech 62,974 impacts collected throughout 2009 and 2010 References: VT Data Mihalik et al Front 34.7% 35.9% Rear 31.9% 30.9% Side 16.3% 14.4% Top 17.1% 18.8% Crisco, J. J., Fiore, R., Beckwith, J. G., Chu, J. J., Brolinson, P. G., Duma, S., Mcallister, T. W., Duhaime, A. C., and Greenwald, R. M., 2010, "Frequency and Location of Head Impact Exposures in Individual Collegiate Football Players," J Athl Train, 45(6), pp Mihalik, J. P., Bell, D. R., Marshall, S. W., and Guskiewicz, K. M., 2007, "Measurement of Head Impacts in Collegiate Football Players: An Investigation of Positional and Event-Type Differences," Neurosurgery, 61(6), pp ; discussion 1235.

61 Head Impact Exposure Comparison to published head impact exposure data: Study Impacts per Season Subjects VT Data (Crisco et al. 2010) 1000 Collegiate Guskiewicz et al Collegiate Schnebel et al Collegiate and High School Broglio et al High School References: Broglio, S. P., Sosnoff, J. J., Shin, S., He, X., Alcaraz, C., and Zimmerman, J., 2009, "Head Impacts During High School Football: A Biomechanical Assessment," J Athl Train, 44(4), pp Crisco, J. J., Fiore, R., Beckwith, J. G., Chu, J. J., Brolinson, P. G., Duma, S., Mcallister, T. W., Duhaime, A. C., and Greenwald, R. M., 2010, "Frequency and Location of Head Impact Exposures in Individual Collegiate Football Players," J Athl Train, 45(6), pp Guskiewicz, K. M., Mihalik, J. P., Shankar, V., Marshall, S. W., Crowell, D. H., Oliaro, S. M., Ciocca, M. F., and Hooker, D. N., 2007, "Measurement of Head Impacts in Collegiate Football Players: Relationship between Head Impact Biomechanics and Acute Clinical Outcome after Concussion," Neurosurgery, 61(6), pp Schnebel, B., Gwin, J. T., Anderson, S., and Gatlin, R., 2007, "In Vivo Study of Head Impacts in Football: A Comparison of National Collegiate Athletic Association Division I Versus High School Impacts," Neurosurgery, 60(3), pp ; discussion

62 Head Impact Exposure While we have the overall exposure that 1 player experiences throughout 1 season, we must define exposure on an impact location basis Percent of Impacts Number of Impacts Front 34.7% 347 Rear 31.9% 319 Side 16.3% 163 Top 17.1% 171 Total 100% 1000 Must determine impact severity exposure for each location so that each can be weighted to reflect what a player actually experiences throughout a season

63 Head Impact Exposure: Front Location Drop Height: none 0 in to 6 in 164 Impacts Drop Height: 12 in 6 in to 18 in 138 Impacts Drop Height: 24 in 18 in to 30 in 31 Impacts Drop Height: 36 in 30 in to 42 in Drop Height: 48 in Drop Height: 60 in 10 Impacts 42 in to 54 in 54 in and above 3 Impacts 1 Impact This analysis is done for each impact location distribution

64 Head Impact Exposure Exposure is defined as a function of drop height and impact location Front Rear Side Top < 19 g in in in in in Total impacts per season

65 STAR Rating System for Football Helmets STAR: Summation of Tests for the Analysis of Risk 4 6 STAR = E ( h ) R ( a ) L= 1 H= 1 R(a): Injury Risk Injury risk as a function of peak linear acceleration

66 ration (rad d/s/s) Rotation nal Accele Volunteer Data Combined Linear and Rotational Risk Risk Contours 1% 50% 25% 10% 5% 75% 90% Linear Acceleration (g) (Rowson and Duma, ABME, 2013) True Positive Rat te Tr rue Positive Rate ROC Curves AUC = HITS Data 63,011 Impacts 244 Concussions False Positive Rate AUC = NFL Data 58 Impacts 25 Concussions False Positive Rate

67 STAR Testing Process For each model, 3 new helmets are tested twice at the 20 STAR matrix (2x20x3 = 120) The two peak accelerations for each testing configuration are averaged. A STAR value for each helmet is determined from the average accelerations for that helmet. The overall STAR value is determined by averaging the three Individual STAR values. Statistical significance between helmet models is determined using the average and variance in the three individual STAR values.

68 STAR Ratings of Current Helmets 5 Stars: Best Available STAR Value: Rawlings Quantum Riddell 360 Rawlings Quantum Plus STAR Value: Cost: $ STAR Value: Cost: $ Riddell Revolution IQ 3 Stars: Good Cost: $ STAR Value: Cost: $ Riddell Revolution Speed STAR Value: Cost: $ Schutt Air XP STAR Value: Cost: $ Stars: Very Good Schutt ION 4D STAR Value: Cost: $ Stars: Adequate Xenith X2 STAR Value: Cost: $ Schutt DNA Pro + STAR Value: Cost: $ Schutt Air Advantage STAR Value: Cost: $ Rawlings Impulse Xenith X1 STAR Value: Cost: $ STAR Value: Cost: $ Star: Marginal Riddell VSR4 NR: Not Recommended STAR Value: Cost: Not Applicable Used helmets were tested to provide a reference Riddell Revolution STAR Value: Cost: $ Adams A2000 Pro Elite STAR Value: Cost: $

69 Do helmets differ in their ability to reduce head acceleration? Yes, as shown by the evidence.

70 Compare Two Popular Helmets Riddell Revolution Riddell VSR4 Acceleration Metrics: NFL: Top group VT: 4 STARs (54% risk reduction) = > < Acceleration Metrics NFL: 2 nd Group VT: 1 STAR (Viano, 2011b; Rowson and Duma, 2011)

71 Clinical Evidence Part 1 Collins et al. (2006) Studied over 2141 high school players Revolution reduced risk of concussion by 31% Peer reviewed, 5 of 6 comments positive (p = 0.03) Primary criticism from Dr. Cantu s letter Older VSR4 helmets compared to newer Revolution helmets, and that older helmets test worse than newer This is not supported by any evidence: there are no publications or data sets that show older helmets are worse

72 Clinical Evidence Part 2 Rowson and Duma, 2012a 9 year study of Virginia Tech football players All new helmets Same team physician Controlled for exposure All helmets were instrumented with sensors 153,486 head impacts for 308 players Revolution reduced risk of concussion by 85% y (p = 0.03) Eliminates only previous criticisms of the Collins work By accounting for exposure, more accurate comparison of helmet performance

73 Clinical Evidence Part 3 Current study, to be published in 2013 (Due to IOM copyright, cannot show all details) 8 college teams All instrumented to account for impact exposure All good/new equipment All have very ygood medical oversight Revolution significantly reduces the risk of Revolution significantly reduces the risk of concussion compared to the VSR4

74 Clinical Validation of STAR 3 different studies show differences between helmets in ability to reduce concussion risk with Revolution Riddell Revolution Riddell VSR4 > STAR Value STAR Value Collins 31% STAR 54% VT 85%

75 Five Year Helmet Rating Plan Using Linear and Rotational Acceleration For Predicting Concussion Risk Adult Football Spring 2013: Ratings Updated** Spring 2014: New Methods Released Spring 2015: New Ratings Spring 2017: Ratings Updated Hockey Youth Football Fall 2013: New Methods Released Baseline Ratings Data Collection Spring 2014: New Methods Released Fall 2015: Ratings Updated Spring 2015: New Ratings Released Fall 2017: Ratings Updated Spring 2017: Ratings Updated Baseball Data Collection Summer 2015: New Methods Released Summer 2016: Ratings Released*** Softball Data Collection Summer 2015: New Methods Released Summer 2016: Ratings Released*** Lacrosse Data Collection Summer 2015: New Methods Released Summer 2016: Ratings Released*** Additional Sports Possible For More Information: *Any player in any sport can sustain a head injury with even the best protection. No helmet can prevent all concussions; however, some helmets better manage the impact energies and result in lower head accelerations, which are correlated to concussion risk. Rating schedule may change depending on data availability. **2013 adult football ratings will use the original S TAR methodology given the three year history and design schedule. The 2014 adult football ratings will utilize the new linear and rotational acceleration risk curve and associated testing methodology (Rowson and Duma 2013, ABME). ***These ratings will be updated on the two-year schedule in 2018

76 Presentation Outline Part 1: Injury Biomechanics Background Reducing injuries in auto-safety, sports, military Part 2: STAR Helmet Rating System Fundamental Questions Review of exposure and risk analysis Part 3: Youth Football Data

77 5,000,000 Football Players in US NFL 2,000 Players College 100, Players High School 1,300, Players 6 to 13 years old 3,500,000 Players Majority of football players are between 6 and 13 years old

78 VT-WFU Youth Study 6 8 Year Olds Auburn Mites 12 Instrumented Players 9 11 Year Olds Blacksburg Juniors 17 Instrumented Players Year Olds Blacksburg Middle School 12 Instrumented Players Age Year Olds South Fork Jr Pee Wee 22 Instrumented Players Year Olds South Fork Pee Wee 21 Instrumented Players Year Olds Ronald Wilson Reagan High School 40 Instrumented Players Head Impact Biomechanics Game and Practice Data Collection Cognitive Testing Pediatric ImPACT Testing for 12.5 years old and under Imaging Baseline, Injury, and Post-Season Instrumentation transmitted impact data to computer during play Helmets were instrumented for each game and practice Adult ImPACT Testing for 12.5 year old and over Linear and Rotational Head Acceleration Measurements FE Modeling for Tissue Response Investigating Correlations fmri: MEG:

79 Youth Football Helmets There are very few differences between adult football helmet and youth football helmets Adult Helmet Youth Helmet Data has not previously been available to design youthspecific helmets

80 Helmet Instrumentation Two parallel systems during past 10 years HIT System 6DOF Device (VT) 6 Accelerometers mounted normal to the skull 3 Linear and Resultant Rotational Accelerations ~$1,000/helmet et Validated by NFL, others 12 Accelerometers mounted tangential 3 Linear and 3 Rotational Accelerations (6DOF) ~$10,000/helmet et Validates HIT System

81 Child Head Acceleration Measurement Data collected wirelessly for every game and practice

82 Game Impact: 20g 40g Range

83 Practice Impact: 50g+ Impact

84 Pediatric Head Impact Data 6 8 Year Olds Auburn Mites 12 Instrumented Players 9 11 Year Olds Blacksburg Juniors 17 Instrumented Players Year Olds Blacksburg Middle School 12 Instrumented Players Age Year Olds Year Olds Year Olds South Fork Jr Pee Wee South Fork Pee Wee Ronald Wilson Reagan High School 22 Instrumented Players 21 Instrumented Players 40 Instrumented Players Players Impacts 3,061 11,978 3,414 16, th 95 th 119 instrumented players under 18 years old 16 g 34,96019 head g impacts recorded 21 g 8 players sustained concussions 37 g 46 g 60 g 22 g 58 g Injuries

85 Conclusions 1. Injury biomechanics involves reducing risk 2. Head acceleration is correlated to concussion risk 3. Helmets vary in their ability to reduce head acceleration 4. Helmets that reduce head acceleration result in lower risk of concussion on the field 5. Youth head impact exposure can be high, especially in practices Much more biomechanical research is needed relative to youth programs in three key areas: regulations, coaching, equipment

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89 Human Impact Tolerance and The STAR Helmet Rating System Stefan M. Duma, Steven Rowson, Joel Stitzel, Ray Daniel, Bryan Cobb, Tyler Young, Brock Strom, Craig McNally, Anna MacAlister, Gunnar Brolinson, Mike Goforth, Mark Rogers, John Shifflett, Alex Powers, Chris Whitlow, Jill Urban, Joseph Maldjian, Elizabeth Davenport Massachusetts Secondary Schools Athletic Directors Association March 20, 2013