Brazilian Jiu-Jitsu (BJJ) is a rapidly growing grappling sport with a wide spectrum of participants. In contrast to combat sports, BJJ focuses on submissions such as joint locks, chokeholds, and control rather than punches and kicks. The goal is to control and submit the opponent as opposed to striking and inducing trauma. This lack of purposeful trauma distinguishes BJJ from combat sports such as boxing and mixed martial arts.
Like other contact grappling sports, there is a risk for concussion. According to the most recent international consensus statement on concussion in sports, a sports-related concussion was defined as “a traumatic brain injury induced by biomechanical forces” [1
]. Sports-related concussion is typically a brief self-resolving impairment in neurologic function. The derangement tends to be functional rather than structural in nature, and therefore is not often seen with neuroimaging studies. The symptoms of a sports-related concussion are broad and varied and do not have to include loss of consciousness (LOC) [1
]. Return to sports and time to recovery from symptoms are also commonly studied among concussed athletes. Athletes with concussions who report more than four symptoms are at an increased risk for symptoms lasting greater than one week [2
There has been limited research of injuries acquired from participation in BJJ. Within the current body of published research, the focus has been on orthopedic injuries and skin infections [3
]. It has been observed that these injuries occur more often during practice than competitions [5
]. Previous research has shown the average BJJ practitioner competes in 2.18 competitions per year and trains 7.63 h per week [5
]. The paucity of competitions relative to practice time is likely a factor in the majority of injuries occurring during practice. The current body of published literature does not include studies that examine the prevalence of concussions among BJJ participants. Exploring the epidemiology of concussion in BJJ may help determine the best strategies for identification, treatment, and prevention of concussions within this sport.
Epidemiological studies on the period prevalence of concussions have been carried out in similar grappling sports such as wrestling. In the National Collegiate Athletic Association (NCAA) wrestling from 2005 to 2006, concussions represented 5.8% of all injuries or 0.42 concussions per 1000 athlete exposures [6
]. During 2011–2015, the concussion rate in NCAA wrestling was reported to be 0.89 per 1000 athlete-exposures [7
]. Data from the NCAA Injury Surveillance System reveal a steady increase in concussion rates across all sports, effectively doubling from 1988 to 2004 [8
]. This increase is most likely to be due to the increasing awareness and reporting; it is, therefore, difficult to compare concussion prevalence estimates over this time period.
A recent study using retrospective self-reporting found the lifetime prevalence of concussion in water polo to be 36% [9
]. The NCAA has carried out similar retrospective self-reporting studies. Among men’s contact sports, the concussion prevalence were 17.8% and 19.5% in lacrosse and wrestling, respectively [10
]. Among women’s contact sports, which did not include grappling sports, the highest concussion prevalence was in ice hockey at 20.9% [10
]. This data set was limited to concussions incurred during an athlete’s NCAA career.
The vast majority of sport-related concussion research focuses on athletes under 30 years of age [8
]. With a significant population of BJJ participants older than 30, there is an opportunity to analyze concussions in a population that are studied less frequently [4
]. It has been shown that musculoskeletal injuries in BJJ occur more frequently in practitioners over age 30, although there has been no research published on brain injuries in this age group [13
]. Outside of BJJ, there is evidence that females are more likely to suffer concussions in a given sport than their male counterparts [12
]. To our knowledge, this phenomenon has yet to be studied within BJJ.
The present study aimed to quantify the lifetime prevalence of concussions among BJJ practitioners to identify factors associated with greater odds of having a concussion. We hypothesize that the lifetime prevalence of concussions will be similar to other grappling sports. We also expect the practitioners who participate in competitions and those who are older to have a greater prevalence of concussions and take longer to return to sports.
As a grappling sport, BJJ puts practitioners at risk for incurring a sports-related concussion. In this retrospective survey, 25.2% of BJJ practitioners report having a concussion while engaging in BJJ in their lifetime. To our knowledge, this is the first study that attempts to record the prevalence of sports-related concussions in BJJ. Several findings were consistent with the recent studies in other sports. For example, the concussion prevalence of 25.2% in this study was similar to the career prevalence of 19.5% reported in NCAA men’s wrestling [10
]. The reported prevalence in NCAA men’s wrestling covers the athletes’ collegiate career, typically ranging from one to five years. It may be more accurate to compare the lifetime prevalence in BJJ to lifetime prevalence in other sports. In a recent study of water polo athletes, 36% of participants reported at least one lifetime concussion in retrospective surveys [9
]. When compared to older national studies, the increase in concussion prevalence found in this study is likely secondary to a more inclusive concussion definition, increased concussion awareness, and the methodology of retrospective surveys. In an anonymous survey, 22% of college athletes indicated that they would be unlikely to report concussion symptoms to a coach or athletic trainer [15
]. Furthermore, it has been estimated that 35–62% of athletes do not report every sustained concussion due to a combination of factors such as lack of knowledge, the pressure to play, and attitudes toward concussion [16
]. Therefore, an anonymous retrospective survey may increase the likelihood of athletes reporting a concussion, particularly given that there is no associated perceived penalty for reporting.
We also found that females were significantly more likely to experience a concussion while participating in BJJ when compared to males (p
< 0.001). In the logistic regression model, gender remained significantly associated with increased odds of suffering a concussion while doing BJJ (Table 2
). This is consistent with previous research, as studies have reported females to have a greater prevalence of concussions in multiple sports [9
]. Our respondent pool consisted of 11.4% female BJJ practitioners (n = 89), which likely reflects the overall proportion in the sport (Table 1
). In future studies, it will be important to follow a greater number of female BJJ practitioners to ensure the significance of observed trends. In contrast to concussions experienced as a result of BJJ participation, there was no significant difference between the reported concussion prevalence of males and females prior to participation in BJJ (X2
(2, n = 774) = 1.930, p
= 0.381). This supports a lack of significant gender bias in reporting concussions within our study. If a gender bias did exist, we would expect to see an increase in reports of both concussions before and while engaging in BJJ.
Incurring a concussion before BJJ was associated with increased odds of having a concussion during BJJ (Table 2
). This is supported in the literature of other non-grappling sports; NCAA football players were shown to have a dose-dependent increased risk of concussion based on their previous self-reported concussion history [17
]. It is also possible that practitioners who are more likely to report a concussion before BJJ are also more likely to report one when participating in BJJ. We attempted to control for this possibility with the anonymity of the survey. In a multiple variable logistic regression model, increased competition density was associated with increased odds for suffering a concussion during BJJ (Table 2
). In a sport that has a wide spectrum of participants, from competitors to casual practitioners, it is likely that those who frequently compete for training also engage with greater intensity. This would be expected to lead to a greater incidence of head trauma.
Among practitioners who had a concussion while engaging in BJJ, there were no increased odds for having a second concussion. We report 21.4% of concussions were recurrent, though this may underestimate the true value as we did not collect data on concussions beyond the second incident. This value is higher than the 8.2% recurrence reported by NCAA wrestling [11
]. The difference may be secondary to sample size or to the enforcement of return to sports guidelines in the NCAA.
The most common reported symptom of a concussion in this study was a headache, as reported by 75.7% of participants (Figure 1
). Headache is typically the most commonly reported symptom by athletes who incur concussions [18
]. Interestingly, the prevalence of concussion symptoms in BJJ was very similar to the results gathered by athletic trainers in high school and college football players. We report 27.6% and 9.9% of participants reporting memory problems and LOC, respectively (Figure 1
). Among football players with concussions, 27.7% and 8.9% experienced amnesia and LOC, respectively [18
]. Similar proportions of concussions with LOC have been seen in prospective studies in rugby [19
]. This suggests that while concussion prevalence may change with data collection methodology, relative symptom prevalence is more consistent across collection methods and sports.
Clinically, the median time participants in this study reported resting after a concussion was three days. The median value was used rather than the mean due to outliers, including three practitioners who reported sitting out six months or greater. Current return to sports guidelines recommended by the Fifth International Conference on Concussion indicates that the amount of time sitting out should include a period of rest followed by the gradual return to sports where the participant remains below a symptom threshold [1
]. Participants’ reported median return to sports time of three days, including 30.3% returning on the same day as being concussed. This suggests that there is a clear need to increase concussion education among BJJ coaches and practitioners (Figure 2
). This is critical in a sport that does not require athletic trainers or medical professionals to monitor practice sessions.
Given the methodology relied on retrospective surveying, there are limitations to this study that are typically seen with retrospective data. With the self-selection involved in survey participation, there is a possibility of systematic bias with over-reporting of concussions in the results. Conversely, by communicating with BJJ coaches and through social media, we may have overlooked individuals who no longer participate in BJJ due to their injury. Because participants are self-reporting injuries, there is a risk of recall bias and response bias. This is amplified by the attempt to gather lifetime concussion history from participants rather than a limited recall period. The fact that 52.2% of concussions before starting BJJ were reported to include a LOC raises concerns of recall bias. Several studies have shown that LOC does not take place in the majority of concussions [18
]. It is likely that participants are underreporting the prevalence of concussions that did not include a LOC. The sample of 778 participants may not be representative of all BJJ practitioners. The survey did not ask BJJ practitioners to report the lifetime total number of concussions sustained. Future analysis should aim to include this value in order to determine the rate of concussions in BJJ. The survey distribution methodology resulted in the inability to estimate the number of participants the survey reached. Thus, we were unable to determine a response rate for the data collected. The study is also limited by the inability to assess the causes of concussions. We are unable to determine if concussions are more commonly associated with the impact onto a surface such as a mat or impact with an opponent. Likewise, we cannot determine if the rate of concussion is higher in practice or in competition. Many of these limitations would be addressed by performing a prospective analysis.
This study provides an initial investigation of concussions within BJJ. There is much research that needs to be done to better understand both concussions and practitioners within the sport. Future research could move in several directions, including a focus on female BJJ practitioners. Although it is difficult to make definitive conclusions without a larger sample size of female practitioners, this study suggests that females may be at an increased risk of concussions. In order to more accurately determine the risk of concussion in BJJ, a prospective injury surveillance study should be carried out using a representative cohort of BJJ practitioners. This will allow for tracking of athlete exposures in order to determine the rate of concussion while identifying risk factors and the mechanisms of concussions incurred while engaging in BJJ. BJJ includes takedowns, grappling while standing, and grappling on the ground. Determining which aspects of the sports may increase the risk of concussion could help determine the safest practices.