In previous posts on my sports-related concussion (SRC) series, I’ve discussed the following topics, feel free to take a look at these as a primer!
Today’s post (Part 1) is going to cover sex differences as it pertains to SRC injury risk and risk factors. In these posts, I strive to present the latest literature and a bit of my thoughts. Let’s begin…
A hot topic in the world of SRCs is the role of sex in determining both injury incidence and recovery outcomes. Recent literature suggests that the rates of SRC injuries are greater in females at the adolescent, collegiate, and professional levels. While the greatest number of SRCs are typically sustained during men’s (American) football, female athletes have demonstrated a greater risk for SRC in several sex-comparable sports, including softball/baseball, basketball, soccer, lacrosse, and ice hockey.5,13 Recent epidemiological studies in collegiate athletes suggest that female basketball and soccer players were 53% and 83% more likely to sustain an SRC compared to males.13 In adolescent athletes in which both sexes participated, the overall SRC was 56% greater in females.6 As with other injuries (eg, ACL), we have been able to identify key differentiating factors between sexes that place female athletes at greater risk for injury. So the question to answer now is…why are females at greater risk for SRC? While there are a few hypotheses, we will first discuss SRC reporting behaviors in male and female athletes.
Reporting an SRC
We know with a reasonable amount of certainty that SRCs are generally underreported, as it’s believed that as many as 50% of all SRCs are not reported to proper medical personnel, particularly in younger athletes.7,12 This issue is especially notable in male athletes competing in high contact sports (eg, football, hockey, lacrosse). Compared to their female counterparts, adolescent males are much less likely to report a suspected SRC due to cultural perceptions that the injury is a sign of weakness.11 Specific reasons may include: pressure from coaches and teammates, not believing the injury was serious, and a general unawareness of SRC symptoms. It is very important to consider the psychosocial aspects of SRC because many (whether we like it or not) self-identify as an athlete first; taking away an athlete’s ability to compete due to a concussive injury can be a severe blow to one’s mental health. A full discussion on the psychological aspects of reporting an SRC is for another day, but keep this mind when you are working with a wide variety of athletes.
Along similar lines, female athletes are much more likely to report greater symptom severity after a concussive event compared to males. Recent research suggests that female high school and collegiate athletes reported significantly more symptoms at 2, 7, and 14 days post-SRC than males,4 specifically on reported headache, difficulty concentrating, and irritability.1 Things get a little interesting with regards to actual symptoms. Is it because females are more truthful in reporting? Or do females sustain more severe symptoms? Females are more likely to report an SRC, but are their injuries actually more severe than males? For these questions, let’s examine sex differences as it pertains to 1) head-neck strength and 2) neurophysiological differences in the male and female brain.
Head-Neck Strength Differences
While males and females experience a similar number of head impacts during sport,8 females may be at greater risk for more severe SRC injuries (prolonged recovery) due to strength and stiffness deficits in the head-neck segment when compared to males.10 The neck musculature is like any other in our body in that eccentric muscular action allows us to attenuate high impact forces. The neck is unique in that it is a multiplanar segment with the ability to decelerate head impact forces in all three planes. Decreased head-neck stiffness (29%), head mass (15–43%), and neck girth (12–30%) are believed to play an influential role in females experiencing greater angular accelerations and displacements during known and unknown force applications.10 Investigations into soccer athletes have determined that females exhibit nearly 50% less neck flexor/extensor strength9 and experience greater head-neck rotational velocities during heading maneuvers.2 While more research related to head impacts are clearly needed in sex-comparable sports, females experiencing greater head-neck accelerations (at similar impact rates) may provide a rationale for greater risk for SRC during sport.
As I alluded to in a previous tweet (https://twitter.com/JasonAvedesian/status/1288083510155079683), neck strengthening is one of the most cost-efficient ways we can reduce SRC risk, particularly in our younger athletes. A recent study by Collins et al. (2014) found thatevery one-pound increase in baseline neck strength was associated with a five percent decrease in SRC risk.3
Given that female athletes tend to have weaker necks, it stands to reason that specific targeting of this musculature will be extremely beneficial to reduce the risk of SRC. While the topic of specific neck strengthening for SRC is outside the scope of this particular blog, I would highly recommend taking a deeper look into neck strengthening strategies for your female athletes.
Stay tuned for Part 2 in this SRC series! I’ll discuss neuropsychological and neurophysiological differences between the sexes and how these relate to SRC injury risk and recovery.
Twitter – @JasonAvedesian
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1. Baker JG, Leddy JJ, Darling SR, Shucard J, Makdissi M, Willer BS. Gender Differences in Recovery From Sports-Related Concussion in Adolescents. Clin Pediatr. 2016;55(8):771-775. doi:10.1177/0009922815606417
2. Bretzin AC, Mansell JL, Tierney RT, McDevitt JK. Sex Differences in Anthropometrics and Heading Kinematics Among Division I Soccer Athletes: A Pilot Study. Sports Health. 2017;9(2):6.
3. Collins CL, Fletcher EN, Fields SK, et al. Neck strength: a protective factor reducing risk for concussion in high school sports. J Prim Prev. 2014;35(5):309-319. doi:10.1007/s10935-014-0355-2
4. Covassin, Harris W, Parker T, Kontos A. The Role of Age and Sex in Symptoms, Neurocognitive Performance, and Postural Stability in Athletes After Concussion. Am J Sports Med. 2012;40(6):1303-1312. doi:10.1177/0363546512444554
5. Kerr ZY, Chandran A, Nedimyer AK, Arakkal A, Pierpoint LA, Zuckerman SL. Concussion Incidence and Trends in 20 High School Sports. Pediatrics. 2019;144(5):e20192180. doi:10.1542/peds.2019-2180
6. O’Connor KL, Baker MM, Dalton SL, Dompier TP, Broglio SP, Kerr ZY. Epidemiology of Sport-Related Concussions in High School Athletes: National Athletic Treatment, Injury and Outcomes Network (NATION), 2011-2012 Through 2013-2014. J Athl Train. 2017;52(3):175-185. doi:10.4085/1062-6050-52.1.15
7. Register-Mihalik JK, Guskiewicz KM, McLeod TCV, Linnan LA, Mueller FO, Marshall SW. Knowledge, Attitude, and Concussion-Reporting Behaviors Among High School Athletes: A Preliminary Study. J Athl Train. 2013;48(5):645-653. doi:10.4085/1062-6050-48.3.20
8. Reynolds BB, Patrie J, Henry EJ, et al. Effects of Sex and Event Type on Head Impact in Collegiate Soccer. Orthopaedic Journal of Sports Medicine. 2017;5(4):232596711770170. doi:10.1177/2325967117701708
9. Tierney RT, Higgins M, Caswell SV, et al. Sex Differences in Head Acceleration During Heading While Wearing Soccer Headgear. J Athl Train. 2008;43(6):578-584.
10. Tierney RT, Sitler MR, Swanik CB, Swanik KA, Higgins M, Torg J. Gender differences in head-neck segment dynamic stabilization during head acceleration. Med Sci Sports Exerc. 2005;37(2):272-279. doi:10.1249/01.mss.0000152734.47516.aa
11. Wallace J, Covassin T, Beidler E. Sex Differences in High School Athletes’ Knowledge of Sport-Related Concussion Symptoms and Reporting Behaviors. Journal of Athletic Training. 2017;52(7):682-688. doi:10.4085/1062-6050-52.3.06
12. Wallace J, Covassin T, Nogle S, Gould D, Kovan J. Knowledge of Concussion and Reporting Behaviors in High School Athletes With or Without Access to an Athletic Trainer. J Athl Train. 2017;52(3):228-235. doi:10.4085/1062-6050-52.1.07
13. Zuckerman SL, Kerr ZY, Yengo-Kahn A, Wasserman E, Covassin T, Solomon GS. Epidemiology of Sports-Related Concussion in NCAA Athletes From 2009-2010 to 2013-2014: Incidence, Recurrence, and Mechanisms. Am J Sports Med. 2015;43(11):2654-2662. doi:10.1177/0363546515599634