Concussion in Professional Football: Biomechanics of the Striking Player—Part 8

OBJECTIVE:Concussive impacts in professional football were simulated in laboratory tests to determine the collision mechanics resulting in injury to the struck player and the biomechanics of the striking players, who were not concussed or neck-injured in the tackle. METHODS:Twenty-seven helmet-to-helmet collisions were reconstructed in laboratory tests using Hybrid III dummies. The head impact velocity, direction, and kinematics matched game video. Translational and rotational head accelerations and six-axis upper neck loads and moments were used to evaluate how the striking player delivered the concussive blow. The neck injury criterion, Nij, was calculated to assess neck injury risks in the striking player. RESULTS:The time-averaged impact force reached 6372 ± 2486 N at 7.2 milliseconds because of 46.8 ± 21.7g head acceleration and 3624 ± 1729 N neck compression force in the striking player. Fifty-seven percent of the load was contributed by neck compression. The striking players had their heads down and lined up the impact axis through their necks and torsos. This allowed momentum transfer with minimal neck bending and increased the effective mass of the striking player to 1.67 times that of the struck player at peak load. The impact caused 94.3 ± 27.5g head acceleration in the concussed players and 67.9 ± 14.5g without concussion (t = 2.06, df = 25, P = 0.025). The striking player's Nij was greater than tolerance in 9 of 27 cases by exceeding the 4000 N neck compression limit. For these cases, the average neck compression force was 6631 ± 977 N (range, 5210–8194 N). Nij was 1.25 ± 0.16 for eight cases above the tolerance Nij = 1.0. CONCLUSION:In the NFL, striking players line up their heads, necks, and torsos to deliver maximum force to the other player in helmet-to-helmet impacts. The concussive force is from acceleration of the striking player's head and torso load through the neck. Even though neck responses exceeded tolerances, no striking player experienced neck injury or concussion. A head-up stance at impact would reduce the torso inertial load in the collision and the risk of concussion in the struck player.

[1]  A. King,et al.  Measurement of Angular Acceleration of a Rigid Body Using Linear Accelerometers , 1975 .

[2]  A I King,et al.  Correlation of field injuries and GM hybrid III dummy responses for lap-shoulder belt restraint. , 1980, Journal of biomechanical engineering.

[3]  L. Thibault,et al.  The pathomechanics and pathophysiology of cervical spinal cord injury , 1995 .

[4]  V. R. Hodgson,et al.  Mechanisms of Cervical Spine Injury During Impact to the Protected Head , 1980 .

[5]  Funk Ff,et al.  Injuries of the cervical spine in football. , 1975 .

[6]  J. Heck.  The Incidence of Spearing During a High School's 1975 and 1990 Football Seasons. , 1996, Journal of athletic training.

[7]  D. Viano,et al.  Concussion in Professional Football: Location and Direction of Helmet Impacts—Part 2 , 2003, Neurosurgery.

[8]  J. Heck.  A survey of new jersey high school football officials regarding spearing rules. , 1995, Journal of athletic training.

[9]  M. P. Weis,et al.  National Athletic Trainers' Association Position Statement: Head-Down Contact and Spearing in Tackle Football. , 2004, Journal of athletic training.

[10]  W C Hayes,et al.  In vitro hyperextension injuries in the human cadaveric cervical spine , 1992, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[11]  B. Sennett,et al.  The National Football Head and Neck Injury Registry: 14-Year Report on Cervical Quadriplegia, 1971 Through 1984 , 1985 .

[12]  Jarrod W. Carter,et al.  Tolerance of the cervical spine to eccentric axial compression. , 2002, Stapp car crash journal.

[13]  B. Sennett,et al.  Spinal injury at the level of the third and fourth cervical vertebrae resulting from the axial loading mechanism: an analysis and classification. , 1987, Clinics in sports medicine.

[14]  J. Maroon,et al.  Football head and neck injuries--an update. , 1980, Clinical neurosurgery.

[15]  C. S. Blyth,et al.  Catastrophic Spine Injuries in Football. , 1989, The Physician and sportsmedicine.

[16]  J S Torg,et al.  The National Football Head and Neck Injury Registry. 14-year report on cervical quadriplegia, 1971 through 1984. , 1986, JAMA.

[17]  N Shewchenko,et al.  Verification of biomechanical methods employed in a comprehensive study of mild traumatic brain injury and the effectiveness of American football helmets. , 2005, Journal of biomechanics.

[18]  John W. Melvin,et al.  RESPONSE OF THE CERVICAL SPINE TO SUPERIOR-INFERIOR HEAD IMPACT , 1981 .

[19]  R. Ching,et al.  Compressive tolerance of the maturing cervical spine. , 2002, Stapp car crash journal.

[20]  L. Thibault,et al.  The Nicolas Andry Award. The pathomechanics and pathophysiology of cervical spinal cord injury. , 1995, Clinical orthopaedics and related research.

[21]  A. Kelikian.  The surgical treatment of hallux valgus using the modified Z-osteotomy. , 1988, Clinics in Sports Medicine.

[22]  N Yoganandan,et al.  Human head-neck biomechanics under axial tension. , 1996, Medical engineering & physics.

[23]  J. Kraus,et al.  Mortality and morbidity from injuries in sports and recreation. , 1984, Annual review of public health.

[24]  Michael Kleinberger,et al.  THE DYNAMIC RESPONSES OF THE CERVICAL SPINE: BUCKLING, END CONDITIONS, AND TOLERANCE IN COMPRESSIVE IMPACTS , 1997 .

[25]  E. McAuley,et al.  Head and neck injuries in college football: An eight-year analysis , 1985, The American journal of sports medicine.

[26]  F. Dimasi,et al.  TRANSFORMATION OF NINE-ACCELEROMETER-PACKAGE (NAP) DATA FOR REPLICATING HEADPART KINEMATICS AND DYNAMIC LOADING. , 1995 .

[27]  J S Torg,et al.  The National Football Head and Neck Injury Registry: 14-year report on cervical quadriplegia (1971-1984). , 1987, Clinics in sports medicine.

[28]  Robert C Cantu,et al.  Brain Injury-related Fatalities in American Football, 1945–1999 , 2003, Neurosurgery.

[29]  Harold J. Mertz,et al.  Hybrid III: The First Human-Like Crash Test Dummy , 1994 .

[30]  F. F. Funk,et al.  Injuries of the cervical spine in football. , 1975, Clinical orthopaedics and related research.

[31]  L. M. Patrick,et al.  Strength and response of the human neck , 1971 .

[32]  A. Gordon.  Concussion in professional football: reconstruction of game impacts and injuries. , 2004, Neurosurgery.

[33]  A. Sances,et al.  Dynamic Characteristics of the Human Cervical Spine , 1995 .

[34]  Elliot J. Pellman.  Background on the National Football League's research on concussion in professional football. , 2003, Neurosurgery.

[35]  Erik G. Takhounts,et al.  DEVELOPMENT OF IMPROVED INJURY CRITERIA FOR THE ASSESSMENT OF ADVANCED AUTOMOTIVE RESTRAINT SYSTEMS - II , 1999 .

[36]  J. Heck.  The incidence of spearing by high school football ball carriers and their tacklers. , 1992, Journal of athletic training.

[37]  C. S. Blyth,et al.  Fatalities from head and cervical spine injuries occurring in tackle football: 40 years' experience. , 1987, Clinics in sports medicine.

[38]  W Goldsmith,et al.  Biomechanics and neuropathology of adult and paediatric head injury , 2002, British journal of neurosurgery.

[39]  J. Torg.  Epidemiology, pathomechanics, and prevention of athletic injuries to the cervical spine. , 1985, Medicine and science in sports and exercise.

[40]  Bernard Saltzberg,et al.  Experimental studies of brain and neck injury , 1981 .

[42]  M. Schneider.  Head and Neck Injuries in Football: Mechanisms, Treatment, and Prevention , 1973 .

[43]  V. Frankel,et al.  Biomechanics of hyperextension injuries to the cervical spine in football , 1980, The American journal of sports medicine.

[44]  R. Truex,et al.  Spinal injury at the level of the third and fourth cervical vertebrae from football. , 1977, The Journal of bone and joint surgery. American volume.

[45]  J S Torg,et al.  The epidemiologic, pathologic, biomechanical, and cinematographic analysis of football-induced cervical spine trauma , 1990, The American journal of sports medicine.

[46]  H J Mertz,et al.  An Assessment of Compressive Neck Loads Under Injury-Producing Conditions. , 1978, The Physician and sportsmedicine.

[47]  N Yoganandan,et al.  Effect of Age and Loading Rate on Human Cervical Spine Injury Threshold , 1998, Spine.