RELIABILITY AND SEX DIFFERENCES OF CHOICE VISUAL-MOTOR REACTION TIME AND FORCE CHARACTERISTICS OF NECK MUSCLES USING A NOVEL TEST
Main Article Content
Abstract
Introduction
Sensorimotor characteristics such as visual-motor reaction time (VMRT), peak force, and rate of force development (RFD) of the neck muscles play an important role in sports-related concussions (SRC). The purpose of this study was to establish reliability and sex differences of neck-specific VMRT and force characteristics of neck muscles using a novel test.
Methods
This is a two-part study. A total of 15 subjects and 49 subjects participated to examine test–retest reliability and sex differences in multidirectional choice VMRT and peak force and RFD values, respectively.
Results
Reliability was moderate for VMRT (Intraclass Correlation Coefficient, ICC = 0.406–0.624) and moderate to excellent for peak force and RFD (ICC = 0.443–0.948). Females had significantly slower VMRT (P < 0.001–0.012), while no sex differences were found in peak force and RFD (P = 0.079–0.763).
Discussion
Future investigations should incorporate these characteristics during baseline testing and examine if they can be identified as prospective risk factors of SRC.
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References
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2. Covassin T, Moran R, Elbin RJ. Sex differ-ences in reported concussion injury rates and time loss from participation: An update of the National Collegiate Athletic Association Injury Surveillance Program from 2004–2005 through 2008–2009. J Athl Train. 2016;51(3):189–94. http://dx.doi.org/10.4085/1062-6050-51.3.05
3. Eckner JT, O’Connor KL, Broglio SP, Ashton-Miller JA. Comparison of head impact exposure between male and female high school ice hockey athletes. Am J Sports Med. 2018;46(9):2253–62. http://dx.doi.org/10.1177/0363546518777244
4. Wallace J, Covassin T, Beidler E. Sex differences in high school athletes’ knowledge of sport-related concussion symptoms and reporting behaviors. J Athl Train. 2017;52(7):682–8. http://dx.doi.org/10.4085/1062-6050-52.3.06
5. Covassin T, Swanik CB, Sachs M, Kendrick Z, Schatz P, Zillmer E, et al. Sex differences in base-line neuropsychological function and concussion symptoms of collegiate athletes. Br J Sports Med. 2006;40(11):923–7; discussion 927. http://dx.doi.org/10.1136/bjsm.2006.029496
6. Collins CL, Fletcher EN, Fields SK, Kluchurosky L, Rohrkemper MK, Comstock RD, et al. Neck strength: A protective factor reducing risk for concussion in high school sports. J Prim Prev. 2014;35(5):309–19. http://dx.doi.org/10.1007/s10935-014-0355-2
7. Mihalik JP, Guskiewicz KM, Marshall SW, Greenwald RM, Blackburn JT, Cantu RC. Does cervical muscle strength in youth ice hockey players affect head impact biomechanics? Clin J Sport Med. 2011;21(5):416–21. http://dx.doi.org/10.1097/JSM.0B013E31822C8A5C
8. Schmidt JD, Guskiewicz KM, Blackburn JT, Mihalik JP, Siegmund GP, Marshall SW. The influence of cervical muscle characteristics on head impact biomechanics in football. Am J Sports Med. 2014;42(9):2056–66. http://dx.doi.org/10.1177/0363546514536685
9. Black SR. Neck strength and concussion in NCAA division I football. Lubbock, TX: Exercise and Sport Science, Texas Tech University; 2007.
10. Nagai T, Ueno R, Rigamonti L, Bates NA, Krause DA, Crowley E, et al. Multidirectional neck strength characteristics in high school football athletes with and without history of sports-related concussion. Ann Sports Med Res. 2020;7(6):1167.
11. Engelman G, Carry P, Sochanska A, Daoud AK, Wilson J, Provance A. Isometric cervical muscular strength in pediatric athletes with multiple concussions. Clin J Sport Med. 2021;31(1):36–41. http://dx.doi.org/10.1097/JSM.0000000000000681
12. Esopenko C, de Souza N, Conway F, Todaro SM, Brostrand K, Womack J, et al. Bigger necks are not enough: An examination of neck circumference in incoming college athletes. J Prim Prev. 2020;41(5):421–9. http://dx.doi.org/10.1007/s10935-020-00600-5
13. Eckner JT, Oh YK, Joshi MS, Richardson JK, Ashton-Miller JA. Effect of neck muscle strength and anticipatory cervical muscle activation on the kinematic response of the head to impulsive loads. Am J Sports Med. 2014;42(3):566–76. http://dx.doi.org/10.1177/0363546513517869
14. Jin X, Feng Z, Mika V, Li H, Viano DC, Yang KH. The role of neck muscle activities on the risk of mild traumatic brain injury in American football. J Biomech Eng. 2017;139(10):101002. http://dx.doi.org/10.1115/1.4037399
15. Eckner JT, Lipps DB, Kim H, Richardson JK, Ashton-Miller JA. Can a clinical test of reaction time predict a functional head-protective response? Med Sci Sports Exerc. 2011;43(3):382–7. http://dx.doi.org/10.1249/MSS.0b013e3181f1cc51
16. Nagai T, Schilaty ND, Bates NA, Bies NJ, McPherson AL, Hewett TE. High school female basketball athletes exhibit decreased knee-specific choice visual-motor reaction time. Scand J Med Sci Sports. 2021;31(8):1699–707. http://dx.doi.org/10.1111/sms.13978
17. Vartiainen MV, Holm A, Lukander J, Lukander K, Koskinen S, Bornstein R, et al. A novel approach to sports concussion assessment: Computerized multilimb reaction times and balance control testing. J Clin Exp Neuropsychol. 2016;38(3):293–307. http://dx.doi.org/10.1080/13803395.2015.1107031
18. Silverman IW. Sex differences in simple visual reaction time: A historical meta-analysis. Sex Roles. 2006;54:57–68. http://dx.doi.org/10.1007/s11199-006-8869-6
19. Ingalhalikar M, Smith A, Parker D, Satterthwaite TD, Elliot MA, Ruparel K, et al. Sex differences in the structural connectome of the human brain. Proc Natl Acad Sci U S A. 2014;111(2):823–8. http://dx.doi.org/10.1073/pnas.1316909110
20. Ristanis S, Tsepis E, Giotis D, Stergiou N, Cerulli G, Georgoulis AD. Electromechanical delay of the knee flexor muscles is impaired after harvesting hamstring tendons for anterior cruciate ligament reconstruction. Am J Sports Med. 2009;37(11):2179–86. http://dx.doi.org/10.1177/0363546509340771
21. Hulsdunker T, Gunasekara N, Mierau A. Short- and long-term stroboscopic training effects on visuo-motor performance in elite youth sports. Part 1: Reaction and behavior. Med Sci Sports Exerc. 2021;53(5):960–72. http://dx.doi.org/10.1249/MSS.0000000000002541
22. Lempke LB, Howell DR, Eckner JT, Lynall RC. Examination of reaction time deficits follow-ing concussion: A systematic review and meta-analysis. Sports Med. 2020;50(7):1341–59. http:// dx.doi.org/10.1007/s40279-020-01281-0
23. Churchill NW, Hutchison MG, Graham SJ, Schweizer TA. Brain function associated with reaction time after sport-related concussion. Brain Imaging Behav. 2021;15(3):1508–17. http://dx.doi.org/10.1007/s11682-020-00349-9
24. Valkeinen H, Ylinen J, Malkia E, Alen M, Hakkinen K. Maximal force, force/time and activation/coactivation characteristics of the neck muscles in extension and flexion in healthy men and women at different ages. Eur J Appl Physiol. 2002;88(3):247–54. http://dx.doi.org/10.1007/s00421-002-0709-y
25. Nagai T, Crowley EM, Manuell E, Bates NA, Stuart MJ, Schilaty ND. Sex differences in multidirectional neck muscular strength characteristics in high school soccer athletes. Arch Sports Med. 2020;4(2):224–32. http://dx.doi.org/10.36959/987/257
26. Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33(1):159–74. http://dx.doi.org/ 10.2307/2529310
27. MacDonald J, Wilson J, Young J, Duerson D, Swisher G, Collins CL, et al. Evaluation of a simple test of reaction time for baseline concussion testing in a population of high school athletes. Clin J Sport Med. 2015;25(1):43–8. http://dx.doi.org/10.1097/JSM.0000000000000096
28. Gaudet CE, Konin J, Faust D. Immediate post-concussion and cognitive testing: Ceiling effects, reliability, and implications for interpretation. Arch Clin Neuropsychol. 2021;36(4):561–9. http://dx.doi.org/10.1093/arclin/acaa074
29. Bujang MA, Baharum N. A simplified guide to determination of sample size requirements for estimating the value of intraclass correlation coef-ficient: A review. Arch Orofac Sci. 2017;12(1):1–11.
30. Furlan L, Sterr A. The applicability of standard error of measurement and minimal detectable change to motor learning research – A behavioral study. Front Hum Neurosci. 2018;12:95. http://dx.doi.org/10.3389/fnhum.2018.00095
31. Nagai T, Abt JP, Sell TC, Clark NC, Smalley BW, Wirt MD, et al. Neck proprioception, strength, flexibility, and posture in pilots with and with-out neck pain history. Aviat Space Environ Med. 2014;85(5):529–35. http://dx.doi.org/10.3357/ASEM.3874.2014
32. Krause DA, Hansen KA, Hastreiter MJ, Kuhn TN, Peichel ML, Hollman JH. A comparison of various cervical muscle strength testing methods using a handheld dynamometer. Sports Health. 2019;11(1):59–63. http://dx.doi.org/10.1177/1941738118812767
33. Almosnino S, Pelland L, Stevenson JM. Retest reliability of force-time variables of neck muscles under isometric conditions. J Athl Train. 2010;45(5):453– 8. http://dx.doi.org/10.4085/1062-6050-45.5.453
34. Broglio SP, Katz BP, Zhao S, McCrea M, McAllister T, Investigators CC. Test–retest reli-ability and interpretation of common concussion assessment tools: Findings from the NCAA-DoD CARE Consortium. Sports Med. 2018;48(5): 1255–68. http://dx.doi.org/10.1007/s40279-017-0813-0
35. Howell DR, Osternig LR, Chou LS. Detection of acute and long-term effects of concussion: Dual-task gait balance control versus computerized neu-rocognitive test. Arch Phys Med Rehabil. 2018; 99(7):1318–24. http://dx.doi.org/10.1016/j.apmr. 2018.01.025
36. Eckner JT, Kutcher JS, Broglio SP, Richardson JK. Effect of sport-related concussion on clinically measured simple reaction time. Br J Sports Med. 2014;48(2):112–8. http://dx.doi.org/10.1136/bjsports-2012-091579
37. Colvin AC, Mullen J, Lovell MR, West RV, Collins MW, Groh M. The role of concussion his-tory and gender in recovery from soccer-related concussion. Am J Sports Med. 2009;37(9):1699– 704. http://dx.doi.org/10.1177/0363546509332497
38. Covassin T, Elbin R, Kontos A, Larson E. Investigating baseline neurocognitive perfor-mance between male and female athletes with a history of multiple concussion. J Neurol Neurosurg Psychiatry. 2010;81(6):597–601. http://dx.doi.org/10.1136/jnnp.2009.193797
39. Tsushima WT, Tsushima VG, Murata NM. ImPACT normative data of ethnically diverse ad-lescent athletes. Clin J Sport Med. 2020;30(1):52–9. http://dx.doi.org/10.1097/JSM.0000000000000567
40. Lavallee AV, Ching RP, Nuckley DJ. Developmental biomechanics of neck musculature. J Biomech. 2013;46(3):527–34. http://dx.doi.org/10.1016/j.jbiomech.2012.09.029
41. Vasavada AN, Danaraj J, Siegmund GP. Head and neck anthropometry, vertebral geometry and neck strength in height-matched men and women. J Biomech. 2008;41(1):114–21. http://dx.doi.org/10.1016/j.jbiomech.2007.07.007
42. Nagai T, Keenan KA, Abt JP, Sell T, Smalley B, Wirt M, et al. A comparison of cervical and trunk musculoskeletal characteristics between female and male army helicopter pilots. Int J Aviat Aeronautics Aerospace. 2016;3(3):1–14. http://dx.doi.org/10.15394/ijaaa.2016.1136
43. Jordan A, Mehlsen J, Bulow PM, Ostergaard K, Danneskiold-Samsoe B. Maximal isometric strength of the cervical musculature in 100 healthy volunteers. Spine (Phila Pa 1976). 1999;24(13):1343–8. http://dx.doi.org/10.1097/00007632-199907010-00012
44. McNair PJ, Depledge J, Brettkelly M, Stanley SN. Verbal encouragement: Effects on maxi-mum effort voluntary muscle action. Br J Sports Med. 1996;30(3):243–5. http://dx.doi.org/10.1136/bjsm.30.3.243
45. Campenella B, Mattacola CG, Kimura IF. Effect of visual feedback and verbal encouragement on con-centric quadriceps and hamstrings peak torque of males and females. Isokinet Exerc Sci. 2000;8:1–6. http://dx.doi.org/10.3233/IES-2000-0033
46. Andersen LL, Aagaard P. Influence of maximal muscle strength and intrinsic muscle contractile properties on contractile rate of force development. Eur J Appl Physiol. 2006;96(1):46–52. http://dx.doi.org/10.1007/s00421-005-0070-z
47. Kroshus E, Baugh CM, Stein CJ, Austin SB, Calzo JP. Concussion reporting, sex, and conformity to traditional gender norms in young adults. J Adolesc. 2017;54:110–9. http://dx.doi.org/10.1016/j.adolescence.2016.11.002
48. Burman E, Lysholm J, Shahim P, Malm C, Tegner Y. Concussed athletes are more prone to injury both before and after their index concussion: A data base analysis of 699 concussed contact sports athletes. BMJ Open Sport Exerc Med. 2016;2(1):e000092. http://dx.doi.org/10.1136/bmjsem-2015-000092
49. Clark JF, Betz BE, Borders LT, Kuehn-Himmler A, Hasselfeld KA, Divine JG. Vision training and reaction training for improving performance and reducing injury risk in athletes. J Sports Perf Vis. 2020;1(1):e8–16. http://dx.doi.org/10.22374/jspv. v2i1.4
50. Clark JF, Graman P, Ellis JK, Mangine RE, Rauch JT, Bixenmann B, et al. An exploratory study of the potential effects of vision training on concussion incidence in football. Optom Vis Perf. 2015;3(2):116–25.
2. Covassin T, Moran R, Elbin RJ. Sex differ-ences in reported concussion injury rates and time loss from participation: An update of the National Collegiate Athletic Association Injury Surveillance Program from 2004–2005 through 2008–2009. J Athl Train. 2016;51(3):189–94. http://dx.doi.org/10.4085/1062-6050-51.3.05
3. Eckner JT, O’Connor KL, Broglio SP, Ashton-Miller JA. Comparison of head impact exposure between male and female high school ice hockey athletes. Am J Sports Med. 2018;46(9):2253–62. http://dx.doi.org/10.1177/0363546518777244
4. Wallace J, Covassin T, Beidler E. Sex differences in high school athletes’ knowledge of sport-related concussion symptoms and reporting behaviors. J Athl Train. 2017;52(7):682–8. http://dx.doi.org/10.4085/1062-6050-52.3.06
5. Covassin T, Swanik CB, Sachs M, Kendrick Z, Schatz P, Zillmer E, et al. Sex differences in base-line neuropsychological function and concussion symptoms of collegiate athletes. Br J Sports Med. 2006;40(11):923–7; discussion 927. http://dx.doi.org/10.1136/bjsm.2006.029496
6. Collins CL, Fletcher EN, Fields SK, Kluchurosky L, Rohrkemper MK, Comstock RD, et al. Neck strength: A protective factor reducing risk for concussion in high school sports. J Prim Prev. 2014;35(5):309–19. http://dx.doi.org/10.1007/s10935-014-0355-2
7. Mihalik JP, Guskiewicz KM, Marshall SW, Greenwald RM, Blackburn JT, Cantu RC. Does cervical muscle strength in youth ice hockey players affect head impact biomechanics? Clin J Sport Med. 2011;21(5):416–21. http://dx.doi.org/10.1097/JSM.0B013E31822C8A5C
8. Schmidt JD, Guskiewicz KM, Blackburn JT, Mihalik JP, Siegmund GP, Marshall SW. The influence of cervical muscle characteristics on head impact biomechanics in football. Am J Sports Med. 2014;42(9):2056–66. http://dx.doi.org/10.1177/0363546514536685
9. Black SR. Neck strength and concussion in NCAA division I football. Lubbock, TX: Exercise and Sport Science, Texas Tech University; 2007.
10. Nagai T, Ueno R, Rigamonti L, Bates NA, Krause DA, Crowley E, et al. Multidirectional neck strength characteristics in high school football athletes with and without history of sports-related concussion. Ann Sports Med Res. 2020;7(6):1167.
11. Engelman G, Carry P, Sochanska A, Daoud AK, Wilson J, Provance A. Isometric cervical muscular strength in pediatric athletes with multiple concussions. Clin J Sport Med. 2021;31(1):36–41. http://dx.doi.org/10.1097/JSM.0000000000000681
12. Esopenko C, de Souza N, Conway F, Todaro SM, Brostrand K, Womack J, et al. Bigger necks are not enough: An examination of neck circumference in incoming college athletes. J Prim Prev. 2020;41(5):421–9. http://dx.doi.org/10.1007/s10935-020-00600-5
13. Eckner JT, Oh YK, Joshi MS, Richardson JK, Ashton-Miller JA. Effect of neck muscle strength and anticipatory cervical muscle activation on the kinematic response of the head to impulsive loads. Am J Sports Med. 2014;42(3):566–76. http://dx.doi.org/10.1177/0363546513517869
14. Jin X, Feng Z, Mika V, Li H, Viano DC, Yang KH. The role of neck muscle activities on the risk of mild traumatic brain injury in American football. J Biomech Eng. 2017;139(10):101002. http://dx.doi.org/10.1115/1.4037399
15. Eckner JT, Lipps DB, Kim H, Richardson JK, Ashton-Miller JA. Can a clinical test of reaction time predict a functional head-protective response? Med Sci Sports Exerc. 2011;43(3):382–7. http://dx.doi.org/10.1249/MSS.0b013e3181f1cc51
16. Nagai T, Schilaty ND, Bates NA, Bies NJ, McPherson AL, Hewett TE. High school female basketball athletes exhibit decreased knee-specific choice visual-motor reaction time. Scand J Med Sci Sports. 2021;31(8):1699–707. http://dx.doi.org/10.1111/sms.13978
17. Vartiainen MV, Holm A, Lukander J, Lukander K, Koskinen S, Bornstein R, et al. A novel approach to sports concussion assessment: Computerized multilimb reaction times and balance control testing. J Clin Exp Neuropsychol. 2016;38(3):293–307. http://dx.doi.org/10.1080/13803395.2015.1107031
18. Silverman IW. Sex differences in simple visual reaction time: A historical meta-analysis. Sex Roles. 2006;54:57–68. http://dx.doi.org/10.1007/s11199-006-8869-6
19. Ingalhalikar M, Smith A, Parker D, Satterthwaite TD, Elliot MA, Ruparel K, et al. Sex differences in the structural connectome of the human brain. Proc Natl Acad Sci U S A. 2014;111(2):823–8. http://dx.doi.org/10.1073/pnas.1316909110
20. Ristanis S, Tsepis E, Giotis D, Stergiou N, Cerulli G, Georgoulis AD. Electromechanical delay of the knee flexor muscles is impaired after harvesting hamstring tendons for anterior cruciate ligament reconstruction. Am J Sports Med. 2009;37(11):2179–86. http://dx.doi.org/10.1177/0363546509340771
21. Hulsdunker T, Gunasekara N, Mierau A. Short- and long-term stroboscopic training effects on visuo-motor performance in elite youth sports. Part 1: Reaction and behavior. Med Sci Sports Exerc. 2021;53(5):960–72. http://dx.doi.org/10.1249/MSS.0000000000002541
22. Lempke LB, Howell DR, Eckner JT, Lynall RC. Examination of reaction time deficits follow-ing concussion: A systematic review and meta-analysis. Sports Med. 2020;50(7):1341–59. http:// dx.doi.org/10.1007/s40279-020-01281-0
23. Churchill NW, Hutchison MG, Graham SJ, Schweizer TA. Brain function associated with reaction time after sport-related concussion. Brain Imaging Behav. 2021;15(3):1508–17. http://dx.doi.org/10.1007/s11682-020-00349-9
24. Valkeinen H, Ylinen J, Malkia E, Alen M, Hakkinen K. Maximal force, force/time and activation/coactivation characteristics of the neck muscles in extension and flexion in healthy men and women at different ages. Eur J Appl Physiol. 2002;88(3):247–54. http://dx.doi.org/10.1007/s00421-002-0709-y
25. Nagai T, Crowley EM, Manuell E, Bates NA, Stuart MJ, Schilaty ND. Sex differences in multidirectional neck muscular strength characteristics in high school soccer athletes. Arch Sports Med. 2020;4(2):224–32. http://dx.doi.org/10.36959/987/257
26. Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33(1):159–74. http://dx.doi.org/ 10.2307/2529310
27. MacDonald J, Wilson J, Young J, Duerson D, Swisher G, Collins CL, et al. Evaluation of a simple test of reaction time for baseline concussion testing in a population of high school athletes. Clin J Sport Med. 2015;25(1):43–8. http://dx.doi.org/10.1097/JSM.0000000000000096
28. Gaudet CE, Konin J, Faust D. Immediate post-concussion and cognitive testing: Ceiling effects, reliability, and implications for interpretation. Arch Clin Neuropsychol. 2021;36(4):561–9. http://dx.doi.org/10.1093/arclin/acaa074
29. Bujang MA, Baharum N. A simplified guide to determination of sample size requirements for estimating the value of intraclass correlation coef-ficient: A review. Arch Orofac Sci. 2017;12(1):1–11.
30. Furlan L, Sterr A. The applicability of standard error of measurement and minimal detectable change to motor learning research – A behavioral study. Front Hum Neurosci. 2018;12:95. http://dx.doi.org/10.3389/fnhum.2018.00095
31. Nagai T, Abt JP, Sell TC, Clark NC, Smalley BW, Wirt MD, et al. Neck proprioception, strength, flexibility, and posture in pilots with and with-out neck pain history. Aviat Space Environ Med. 2014;85(5):529–35. http://dx.doi.org/10.3357/ASEM.3874.2014
32. Krause DA, Hansen KA, Hastreiter MJ, Kuhn TN, Peichel ML, Hollman JH. A comparison of various cervical muscle strength testing methods using a handheld dynamometer. Sports Health. 2019;11(1):59–63. http://dx.doi.org/10.1177/1941738118812767
33. Almosnino S, Pelland L, Stevenson JM. Retest reliability of force-time variables of neck muscles under isometric conditions. J Athl Train. 2010;45(5):453– 8. http://dx.doi.org/10.4085/1062-6050-45.5.453
34. Broglio SP, Katz BP, Zhao S, McCrea M, McAllister T, Investigators CC. Test–retest reli-ability and interpretation of common concussion assessment tools: Findings from the NCAA-DoD CARE Consortium. Sports Med. 2018;48(5): 1255–68. http://dx.doi.org/10.1007/s40279-017-0813-0
35. Howell DR, Osternig LR, Chou LS. Detection of acute and long-term effects of concussion: Dual-task gait balance control versus computerized neu-rocognitive test. Arch Phys Med Rehabil. 2018; 99(7):1318–24. http://dx.doi.org/10.1016/j.apmr. 2018.01.025
36. Eckner JT, Kutcher JS, Broglio SP, Richardson JK. Effect of sport-related concussion on clinically measured simple reaction time. Br J Sports Med. 2014;48(2):112–8. http://dx.doi.org/10.1136/bjsports-2012-091579
37. Colvin AC, Mullen J, Lovell MR, West RV, Collins MW, Groh M. The role of concussion his-tory and gender in recovery from soccer-related concussion. Am J Sports Med. 2009;37(9):1699– 704. http://dx.doi.org/10.1177/0363546509332497
38. Covassin T, Elbin R, Kontos A, Larson E. Investigating baseline neurocognitive perfor-mance between male and female athletes with a history of multiple concussion. J Neurol Neurosurg Psychiatry. 2010;81(6):597–601. http://dx.doi.org/10.1136/jnnp.2009.193797
39. Tsushima WT, Tsushima VG, Murata NM. ImPACT normative data of ethnically diverse ad-lescent athletes. Clin J Sport Med. 2020;30(1):52–9. http://dx.doi.org/10.1097/JSM.0000000000000567
40. Lavallee AV, Ching RP, Nuckley DJ. Developmental biomechanics of neck musculature. J Biomech. 2013;46(3):527–34. http://dx.doi.org/10.1016/j.jbiomech.2012.09.029
41. Vasavada AN, Danaraj J, Siegmund GP. Head and neck anthropometry, vertebral geometry and neck strength in height-matched men and women. J Biomech. 2008;41(1):114–21. http://dx.doi.org/10.1016/j.jbiomech.2007.07.007
42. Nagai T, Keenan KA, Abt JP, Sell T, Smalley B, Wirt M, et al. A comparison of cervical and trunk musculoskeletal characteristics between female and male army helicopter pilots. Int J Aviat Aeronautics Aerospace. 2016;3(3):1–14. http://dx.doi.org/10.15394/ijaaa.2016.1136
43. Jordan A, Mehlsen J, Bulow PM, Ostergaard K, Danneskiold-Samsoe B. Maximal isometric strength of the cervical musculature in 100 healthy volunteers. Spine (Phila Pa 1976). 1999;24(13):1343–8. http://dx.doi.org/10.1097/00007632-199907010-00012
44. McNair PJ, Depledge J, Brettkelly M, Stanley SN. Verbal encouragement: Effects on maxi-mum effort voluntary muscle action. Br J Sports Med. 1996;30(3):243–5. http://dx.doi.org/10.1136/bjsm.30.3.243
45. Campenella B, Mattacola CG, Kimura IF. Effect of visual feedback and verbal encouragement on con-centric quadriceps and hamstrings peak torque of males and females. Isokinet Exerc Sci. 2000;8:1–6. http://dx.doi.org/10.3233/IES-2000-0033
46. Andersen LL, Aagaard P. Influence of maximal muscle strength and intrinsic muscle contractile properties on contractile rate of force development. Eur J Appl Physiol. 2006;96(1):46–52. http://dx.doi.org/10.1007/s00421-005-0070-z
47. Kroshus E, Baugh CM, Stein CJ, Austin SB, Calzo JP. Concussion reporting, sex, and conformity to traditional gender norms in young adults. J Adolesc. 2017;54:110–9. http://dx.doi.org/10.1016/j.adolescence.2016.11.002
48. Burman E, Lysholm J, Shahim P, Malm C, Tegner Y. Concussed athletes are more prone to injury both before and after their index concussion: A data base analysis of 699 concussed contact sports athletes. BMJ Open Sport Exerc Med. 2016;2(1):e000092. http://dx.doi.org/10.1136/bmjsem-2015-000092
49. Clark JF, Betz BE, Borders LT, Kuehn-Himmler A, Hasselfeld KA, Divine JG. Vision training and reaction training for improving performance and reducing injury risk in athletes. J Sports Perf Vis. 2020;1(1):e8–16. http://dx.doi.org/10.22374/jspv. v2i1.4
50. Clark JF, Graman P, Ellis JK, Mangine RE, Rauch JT, Bixenmann B, et al. An exploratory study of the potential effects of vision training on concussion incidence in football. Optom Vis Perf. 2015;3(2):116–25.