Head injuries in Judo and possible differences between Judo and BJJ
The studies1 quoted in this answer about head and neck injuries in judo come to the conclusion that:
- severe injuries in judo are rare, but when they do occur they are mostly to the brain and spine, mostly occur during throws (as opposed to chokes), and mostly occur due to 'bad falling'
- repeatedly being thrown or choked (as a competitive judoka) does not result in chronic brain injuries
Two differences between BJJ and Judo which may make contribute to higher injury rates in BJJ:
- neck cranks are permitted in BJJ
- in many clubs breakfalling is not practised to the same extent as in judo
Since the authors of the above study explicitly cite "lack of falling skills" among "inexperienced" judoka (those practising < 3 years) as the most prominent cause for head injuries in judo, this last point seems particularly pertinent.
Choke induced injuries in BJJ
A study of injuries in BJJ5 reported only one injury from choking techniques, being a neck strain:
There was 1 neck injury, a cervical strain, caused by the BJJ “triangle” technique, a type of choke (Figure 2).
There is also a single case study16 of a person suffering a carotid dissection and subsequent permanent weakness on the right side of their body, forcing their retirement. The author of the case study notes that though such arterial dissections have been noted before in other martial arts, they are usually the result of strikes, not chokes. As such, they hypothesize the following:
... this particular dissection involved the origin of internal carotid artery, suggesting the following biomechanical sequence:
- carotid artery compression, creating a point of fixation and
- subsequent hyperextension of the neck, with contralateral head rotation.22)
The resultant traction would suffice to stretch and rupture the intimal layer of carotid artery distal to its point of fixation (Fig. 3).
Artistic rendering of Brazilian Jiu-Jitsu maneuver known as Rear Naked Choke or Lion Killer: combined neck extension and head rotation (as a defense measure) stretches the compressed internal carotid artery at its origin, causing dissection.
Take-down/strike induced head injuries in BJJ
A second study22 found that a quarter of BJJ practitioners reported concussion as a result of practice:
This study provides an initial examination of sports-related concussion in BJJ practitioners. Through retrospective surveys, we have shown that 25.2% of BJJ practitioners reported having a concussion while engaging in BJJ.
Comprehensive analysis of injury rates, types, and causes in BJJ
A more comprehensive study19 of injuries in BJJ vs Judo and MMA finds head injuries to be more prevalent than in Judo, and that the majority of injuries in BJJ were sustained via being struck or take-downs:
From 2008 through 2015, U.S. EDs saw an estimated 12,538 injuries resulting from BJJ participation, and the head (21%) and trunk (20%) were the most commonly injured body regions. Judo participation resulted in an estimated 10,102 injuries nationally, and the leg (21%) and the shoulder (20%) regions were injured most often.
Lastly, among the sub-sample with sufficient data to determine what events lead up to the injury—47% for BJJ and 48% for Judo—a majority of individuals were injured from being struck or landing (BJJ 65% and Judo 57%).
The study reports that the most common head injury in BJJ was lacerations:
Concussions were the most commonly occurring head injuries for MMA (38%) and Judo (37%); lacerations were the most common head injury for BJJ (25%).
Our study found striking to be a leading cause of injury for both the striking
sport, MMA, and non-striking sports, BJJ and Judo. This finding may indicate that
the rules prohibiting striking in BJJ and Judo are not sufficient or require better
monitoring or enforcement.
And that injuries more often occur in training than in competition:
The majority of BJJ (9390 [95% CI 4961, 13,820]) and Judo (5771 [95% CI 4334, 7207]) injuries occurred during non-competitive grappling, while the majority of MMA injuries (9086 [95% CI 4325, 13,848]) occurred during competitions.
The study comes to the conclusion that many injuries could be avoided in BJJ by increased training in ukemi:
The most frequently injured body parts for BJJ that we found were the head, neck
and trunk, which is inconsistent with prior research showing the knee and elbow
were injured most often (Kreiswirth et al., 2014; Scoggin III et al., 2014), but may be explained by the wider variety of takedowns permitted and the dynamic use of one’s core. However, the most injured body parts in BJJ competitions were the arm and shoulder, which may be due to the use of joint locks, but remains ambiguous; most narratives mentioned the patient feeling a ‘‘pop’’ before their injury and only one narrative mentioned a ‘‘wrist bar’’ maneuver contributing to injury. Lastly, a large proportion of competitors’ injuries to the head, neck, and trunk in BJJ were a result of their opponent landing on them or accidently striking them. Our findings indicate that numerous injuries could potentially be avoided by increased training in proper falling techniques as is frequently taught in Judo (Pocecco et al., 2013), as well as protective gear that better absorbs the impact of accidental strikes.
9. Common Injuries of Recreational Jiu-Jitsu, 2016
12. Prevalence of Injuries during Brazilian Jiu-Jitsu Training, 2017
25. Brazilian Jiu-Jitsu Injury in Training Survey, 2019
3. The prevalence of injuries in Jiu-Jitsu according to the report of the athletes participating in 2006 world..., 2012
5. Assessment of Injuries During Brazilian Jiu-Jitsu Competition, 2014
6. Incidence of Injury Among Male Brazilian Jiujitsu Fighters at the World Jiu-Jitsu No-Gi Championship 2009, 2014
11. Sports injuries and ill-health episodes in the Cali 2013 World Games, 2016
20. Injury prevalence in Brazilian jiu-jitsu athletes: comparison between different competitive levels, 2018
7. Chronic low back pain and disability in Brazilian jiu-jitsu athletes, 2015
8. Isolated lateral collateral ligament complex injury in rock climbing and Brazilian Jiu-jitsu, 2015
16. Internal Carotid Artery Dissection in Brazilian Jiu-Jitsu, 2017
18. Analysis of the Pattern and Mechanism of Elbow Injuries Related to Armbar-Type Armlocks in Jiu-Jitsu Fighters, 2017
21. Degenerative Changing in Digits of Brazilian Jiujitsu Fighter, 2018
22. Epidemiology of Sports Related Concussion in Brazilian Jiu-Jitsu: A Cross-Sectional Study, 2019
24. Injuries to the Stomatognathic System in Brazilian Jiu-Jitsu Athletes, 2019
1. Injuries in judo: a systematic literature review including suggestions for prevention, 2013
2. Lesões no jiu-jitsu: estudo em 78 atletas, 2004
4. Gi or No-Gi? – An analysis of injury trends in Gi and No-Gi Brazilian Jiu-Jitsu, 2013
10. Prevalence of Injuries in Jiu-Jitsu and Judo Athletes of Portugal South: Associated Injury Mechanisms, 2016
13. Could current factors be associated with retrospective sports injuries in Brazilian jiu-jitsu? A cross-sectional study, 2017
14. Evaluation of Mechanisms and Types of Injuries in Jiu-Jitsu Athletes, 2017
15. Injury History, Severity, and Medical Care for Athletes Participating in Brazilian Jiu-Jitsu, 2017
17. Assessment of Brazilian jiu-jitsu related injuries by severity, type and area, 2017
19. Brazilian Jiu Jitsu, Judo, and Mixed Martial Arts Injuries Presenting to US Emergency Departments, 2008–2015, 2018
23. Epidemiological Study of Brazilian Judo Injuries, 2019
26. Injury rate and pattern among Brazilian jiu-jitsu practitioners: A survey study, 2019
Tables from study: