The performance characteristics of football helmets are currently evaluated by simulating head impacts in the laboratory using a linear drop test method. To encourage development of helmets designed to protect against concussion, the National Operating Committee for Standards in Athletic Equipment recently proposed a new headgear testing methodology with the goal of more closely simulating in vivo head impacts. This proposed test methodology involves an impactor striking a helmeted headform, which is attached to a nonrigid neck. The purpose of the present study was to compare headform accelerations recorded according to the current (n=30) and proposed (n=54) laboratory test methodologies to head accelerations recorded in the field during play. In-helmet systems of six single-axis accelerometers were worn by the Dartmouth College men’s football team during the 2005 and 2006 seasons (n=20,733 impacts; 40 players). The impulse response characteristics of a subset of laboratory test impacts (n=27) were compared with the impulse response characteristics of a matched sample of in vivo head accelerations (n=24). Second- and third-order underdamped, conventional, continuous-time process models were developed for each impact. These models were used to characterize the linear head/headform accelerations for each impact based on frequency domain parameters. Headform linear accelerations generated according to the proposed test method were less similar to in vivo head accelerations than headform accelerations generated by the current linear drop test method. The nonrigid neck currently utilized was not developed to simulate sport-related direct head impacts and appears to be a source of the discrepancy between frequency characteristics of in vivo and laboratory head/headform accelerations. In vivo impacts occurred 37% more frequently on helmet regions, which are tested in the proposed standard than on helmet regions tested currently. This increase was largely due to the addition of the facemask test location. For the proposed standard, impactor velocities as high as 10.5 m/s were needed to simulate the highest energy impacts recorded in vivo. The knowledge gained from this study may provide the basis for improving sports headgear test apparatuses with regard to mimicking in vivo linear head accelerations. Specifically, increasing the stiffness of the neck is recommended. In addition, this study may provide a basis for selecting appropriate test impact energies for the standard performance specification to accompany the proposed standard linear impactor test method.

1.
Mueller
,
F. O.
, 1998, “
Fatalities From Head and Cervical Spine Injuries Occurring in Tackle Football: 50 Years’ Experience
,”
Clin. Sports Med.
0278-5919,
17
(
1
), pp.
169
182
.
2.
NOCSAE
, 2007, “
Standard Drop Test Method and Equipment Used in Evaluating the Performance Characteristics of Protective Headgear
,” Paper No. 001-06m07.
3.
Gurdjian
,
E. S.
,
Lissner
,
H. R.
,
Latimer
,
F. R.
,
Haddad
,
B. F.
, and
Webster
,
J. E.
, 1953, “
Quantitative Determination of Acceleration and Intracranial Pressure in Experimental Head Injury
,”
Neurology
0028-3878,
3
, pp.
417
423
.
4.
Gurdjian
,
E. S.
,
Webster
,
J. E.
, and
Lissner
,
H. R.
, 1955, “
Observations on the Mechanism of Brain Concussion, Contusion, and Laceration
,”
Surg. Gynecol. Obstet.
0039-6087,
101
, pp.
680
690
.
5.
Gurdjian
,
E. S.
,
Roberts
,
V. L.
, and
Thomas
,
L. M.
, 1966, “
Tolerance Curves of Acceleration and Intracranial Pressure and Protective Index in Experimental Head Injury
,”
J. Trauma
0022-5282,
6
(
5
), pp.
600
604
.
6.
Gadd
,
C. W.
, 1966, “
Use of a Weighted-Impulse Criterion for Estimating Injury Hazard
,”
Proceedings of the 10th Stapp Car Crash Conference
,
Society of Automotive Engineers
.
7.
Hodgson
,
V.
, 1970, “
Testing the Validity and Limitations of the Severity Index
,”
Proceedings of the 14th Stapp Car Crash Conference
,
Society of Automotive Engineers
.
8.
Hodgson
,
V.
, 1975, “
National Operating Committee on Standards for Athletic Equipment Football Helmet Certification Program
,”
Med. Sci. Sports Exercise
0195-9131,
7
, pp.
225
232
.
9.
Langlois
,
J. A.
,
Rutland-Brown
,
W.
, and
Wald
,
M. M.
, 2006, “
The Epidemiology and Impact of Traumatic Brain Injury: A Brief Overview
,”
J. Head Trauma Rehabil.
0885-9701,
21
, pp.
375
378
.
10.
Guskiewicz
,
K. M.
,
Weaver
,
N. L.
,
Padua
,
D. A.
, and
Garrett
,
W. E.
, Jr.
, 2000, “
Epidemiology of Concussion in Collegiate and High School Football Players
,”
Am. J. Sports Med.
0363-5465,
28
, pp.
643
650
.
11.
Brazarian
,
J. J.
,
McClung
,
J.
,
Shah
,
M. N.
,
Cheng
,
Y. T.
,
Flesher
,
W.
, and
Kraus
,
J.
, 2005, “
Mild Traumatic Brain Injury in the United States, 1998–2000
,”
Brain Inj
0269-9052,
19
(
2
), pp.
85
91
.
12.
NIH Consensus Development Panel
, 1999, “
Rehabilitation of Persons With Traumatic Brain Injury
,”
JAMA, J. Am. Med. Assoc.
0098-7484,
282
(
10
), pp.
974
983
.
13.
National Center for Injury Prevention and Control
, 2003, “
Report to Congress on Mild Traumatic Brain Injury in the United States: Steps to Prevent a Serious Public Health Problem
,”
Centers for Disease Control and Prevention
,
Atlanta, GA
.
14.
Ruff
,
R.
, 2005, “
Two Decades of Advance in Understanding of Mild Traumatic Brain Injury
,”
J. Head Trauma Rehabil.
0885-9701,
20
(
1
), pp.
5
18
.
15.
NOCSAE
, 2006, “
Standard Linear Impactor Test Method and Equipment Used in Evaluating the Performance Characteristics of Protective Headgear and Faceguards
,” Paper No. 081-04m04.
16.
Hodgson
,
V.
, 1982, “
A Standard for Protective Equipment
,”
Athletic Injuries to the Head, Neck, and Face
,
J.
Torg
, ed.,
Lea & Febiger
,
Philadelphia
, pp.
27
35
.
17.
Crisco
,
J. J.
,
Chu
,
J. J.
, and
Greenwald
,
R. M.
, 2004, “
An Algorithm for Estimating Acceleration Magnitude and Impact Location Using Multiple Non-Orthogonal Single-Axis Accelerometers
,”
ASME J. Biomech. Eng.
0148-0731,
126
, pp.
849
854
.
18.
Duma
,
S. M.
,
Manoogian
,
S. J.
,
Bussone
,
W. R.
,
Brolinson
,
P. G.
,
Goforth
,
M. W.
,
Donnenwerth
,
J. J.
,
Greenwald
,
R. M.
,
Chu
,
J. J.
, and
Crisco
,
J. J.
, 2005, “
Analysis of Real-Time Head Accelerations in Collegiate Football Players
,”
Clin. J. Sport Med.
1050-642X,
15
(
1
), pp.
3
8
.
19.
Brolinson
,
P. G.
,
Manoogian
,
S.
,
McNeely
,
D.
,
Goforth
,
M.
,
Greenwald
,
R.
, and
Duma
,
S.
, 2006, “
Analysis of Linear Head Accelerations From Collegiate Football Impacts
,”
Curr. Sports Med. Rep.
,
5
, pp.
23
28
. 1537-890X
20.
Schnebel
,
B.
,
Gwin
,
J. T.
,
Anderson
,
S.
, and
Gatlin
,
R.
, 2006, “
In Vivo Study of Head Impacts in Football: A Comparison of NCAA Divison I vs. High School Impacts
,”
Neurosurgery
0148-396X,
60
(
3
), pp.
490
495
.
21.
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
0148-396X,
61
(
6
), pp.
1244
52
.
22.
McCaffrey
,
M. A.
,
Mihalik
,
J. P.
,
Crowell
,
D. H.
,
Shields
,
E. W.
, and
Guskiewicz
,
K. M.
, 2007, “
Measurement of Head Impacts in Collegiate Football Players: Clinical Measures of Concussion After High- and Low-Magnitude Impacts
,”
Neurosurgery
0148-396X,
61
(
6
), pp.
1236
43
.
23.
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
0148-396X,
61
(
6
), pp.
1229
35
.
24.
Greenwald
,
R.
,
Gwin
,
J.
,
Chu
,
J.
, and
Crisco
,
J.
, 2008, “
Head Impact Severity Measures for Evaluating Mild Traumatic Brain Injury Risk Exposure
,”
Neurosurgery
0148-396X,
62
(
4
), pp.
789
98
.
25.
Gwin
,
J. T.
,
Chu
,
J. J.
,
McAllister
,
T. A.
, and
Greenwald
,
R. M.
, 2009, “
In-Situ Measures of Head Impact Acceleration in NCAA Division I Men’s Ice Hockey: Implications for ASTM F1045 and Other Ice Hockey Helmet Standards
,”
J. ASTM Int.
1546-962X,
6
(
6
), p.
101848
.
26.
Manoogian
,
S.
,
McNeely
,
D.
, and
Duma
,
S.
, 2006, “
Head Acceleration is Less Than 10 Percent of Helmet Acceleration in Football Impacts
,”
Biomed. Sci. Instrum.
0067-8856,
42
, pp.
383
388
.
27.
Rowson
,
S.
,
Brolinson
,
G.
,
Goforth
,
M.
,
Dietter
,
D.
, and
Duma
,
S.
, 2009, “
Linear and Angular Head Acceleration Measurements in Collegiate Football
,”
ASME J. Biomech. Eng.
0148-0731,
131
(
6
), p.
061016
.
28.
NOCSAE
, 2005, “
Standard Performance Specification for Newly Manufactured Football Helmets
,” Paper No. 002-98m05.
29.
Newman
,
J. A.
,
Beusenberg
,
M. C.
,
Shewchenko
,
N.
,
Withnall
,
C.
, and
Fournier
,
E.
, 2005, “
Verification of Biomechanical Methods Employed in a Comprehensive Study of Mild Traumatic Brain Injury and the Effectiveness of American Football Helmets
,”
J. Biomech.
0021-9290,
38
(
7
), pp.
1469
1481
.
30.
Pellman
,
E. J.
,
Viano
,
D. C.
,
Tucker
,
A. M.
, and
Casson
,
I. R.
, 2003b, “
Concussion in Professional Football: Location and Direction of Helmet Impacts—Part 2
,”
Neurosurgery
0148-396X,
53
, pp.
1328
1341
.
31.
Rosner
,
B.
, 1990,
Fundamentals of Biostatistics
, 3rd ed.,
Harvard University Press
,
Cambridge, MA
.
32.
Zerbe
,
G. O.
,
Archer
,
P. G.
,
Banchero
,
N.
, and
Lechner
,
A. J.
, 1982, “
On Comparing Regression Lines With Unequal Slopes
,”
Am. J. Physiol.
0002-9513,
242
, pp.
178
180
.
33.
Committee on Head Injury Nomenclature of the Congress of Neurological Surgeons
, 1966, “
Glossary of Head Injury Including Some Definitions of Injury to the Cervical Spine
,”
Clin. Neurosurg.
0069-4827,
12
, pp.
386
394
.
34.
Versace
,
J.
, 1971, “
A Review of the Severity Index
,”
Proceedings of the 15th Stapp Car Crash Conference
, Warrendale, SAE Paper No. 710881, pp.
771
796
.
35.
Pellman
,
E. J.
,
Viano
,
D. C.
,
Tucker
,
A. M.
,
Casson
,
I. R.
, and
Waeckerle
,
J. F.
, 2003a, “
Concussion in Professional Football: Reconstruction of Game Impacts and Injuries
,”
Neurosurgery
0148-396X,
53
, pp.
799
814
.
36.
Foster
,
J. K.
,
Kortge
,
J. O.
, and
Wolanin
,
M. J.
, 1977, “
Hybrid III-A Biomechanically Based Crash Test Dummy
,”
Proceedings of the 21st Stapp Car Crash Conference
. SAE Paper No. 770938.
37.
Cantu
,
R. C.
, 2000, “
Biomechanics of Head Injury
,”
Neurologic Athletic Head and Spine Injuries
,
R.
Cantu
, ed.,
W.B. Saunders Co.
,
Philadelphia
, pp.
1
5
.
38.
King
,
A. I.
,
Yang
,
K. H.
,
Zhang
,
L.
, and
Hardy
,
W.
, 2003, “
Is Head Injury Caused by Linear or Angular Acceleration?
,”
International Research Council on the Biomechanics of Impact Annual Conference
, Lisbon, Portugal.
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