Incidence of Injury Among Male Brazilian Jiujitsu Fighters at the World Jiu-Jitsu No-Gi Championship 2009

The World Jiu-Jitsu No-Gi Championship 2009 was held in Long Beach, California. Participant enrollment included a convenience sample of 951 male fighters aged 18 to 50 years. All fighters were eligible and were followed in the study. The belt rank of BJJ fighters consisted of blue (least skill-experienced), purple, brown, and black belt (most skill-experienced) levels. Chart data were collected retrospectively, and the Institutional Review Board of Concordia University, Irvine, California, approved this study.

The tournament director instructed all BJJ fighters who sustained injuries during the tournament to seek medical assessment and clearance from a certified athletic trainer at the medical area (Figure 1). Injury was defined as a situation in which the fighter either requested medical treatment or was unable to continue a contest due to pain or discomfort. The final diagnosis of the injury was triangulated among a certified athletic trainer, physical therapist, and medical doctor for assessment. In addition, any fighter who sustained an injury that was evaluated on the mat area by the certified athletic trainer was evaluated further in the medical area. The proximal location of the medical area to the competition mats ensured high accuracy for capturing each injury sustained during the tournament (Figure 1). Data that met the inclusion criteria were categorized by joint (shoulder, elbow, knee, or ankle) and aggregated. Given that BJJ focuses on submission joint locks to subdue an opponent to achieve match victory, other reported injuries, such as back, rib, and skin injuries, also were recorded but were not included in the musculoskeletal joint analysis.

At the medical tent of the tournament, the certified athletic trainers used a specially designed questionnaire to record each fighter's sex, age, mass, belt level, years of experience in BJJ, number of training days per week, and number of matches in the tournament.

An athlete-exposure (AE) was calculated as any match in which a BJJ fighter was at risk of sustaining an injury. The total number of AEs was determined by multiplying the cumulative number of matches by 2 because 2 competitors were involved in each match.⁶  This method of determining total AEs has been used in previous studies concerning injuries in athletic competitions.^1,9–11 

The incidence rate was defined as the number of injuries per 1000 AEs. Fighters were categorized into belt graduation levels for group comparisons (belt rank progression level: blue, purple, brown, and black). Incidence rate ratios and 95% confidence intervals were calculated to determine differences among sex, belt rank, injury type, and body region or part. The α level was set at .05. All analyses were conducted with STATA (version 5.0; STATA Corp, College Station, TX).

Injury data by body part and belt are presented in Tables 1 and 2, respectively. Of the 951 BJJ fighters who competed during the tournament, 62 injuries (62 athletes) and 1606 AEs were reported, for an overall incidence rate of 38.6 injuries per 1000 AEs. The injured fighters had a mean age of 29.4 ± 5.7 years, height of 69.4 ± 5.7 cm, and mass of 173.7 ± 5.6 lb (78.8 ± 2.5 kg). A total of 40 of the 62 injuries affected the joints, for an incidence rate of 24.9 injuries per 1000 AEs. Other injuries included lacerations, epistaxis, rib pain, and skin abrasions. The incidence rate of joint injury was highest at the elbow and knee (both 7.5 injuries per 1000 AEs). Comparatively, incidence rates at the shoulder and ankle were 5.0 injuries per 1000 AEs. The incidence rate for joint injuries for each belt rank was 21.5 injuries per 1000 AEs for blue, 21.3 injuries per 1000 AEs for purple, 25.2 injuries per 1000 AEs for brown, and 35.1 injuries per 1000 AEs for black (Figure 2). No differences were found for incidence rate ratios of joint injury among individual belt groups (P > .05). In addition, the more skill-experienced (brown belt and black belt) fighters had a higher injury risk than the less skill-experienced (blue belt and purple belt) fighters, but the finding was not significantly different (incidence rate ratio = 1.65, 95% confidence interval = 0.9, 2.9; P = .06). Injuries by location for each belt rank are presented in Figure 3. Percentages of other injuries accounting for the total injury count of each belt rank were 33.3% (n = 7) for blue belt, 27.3% (n = 3) for purple belt, 50% (n = 6) for brown belt, and 22.2% (n = 4) for black belt.

To our knowledge, we provide one of the first large-scale epidemiologic reports describing the risk of injury in BJJ. The elbow and knee had the highest incidences of joint injury. Whereas the more skilled fighters (brown and black belts) had a greater risk of injury in this tournament, few differences were found between fighter experience or skill level and location of joint injury.

Our findings are consistent with those reported in similar sports, such as collegiate wrestling, in which the more experienced wrestlers had higher frequencies of injury than their less experienced counterparts.^1,12,13  Researchers¹⁴  have reported injury incidences and rates that were lower for high school than collegiate wrestlers. Comparably, these data have suggested higher injury rates for more experienced wrestlers and a higher incidence of injury by joint location.

Investigators have indicated the incidence of upper extremity injuries in high school wrestlers was higher^1,9,15  than the incidence of lower extremity injuries in collegiate wrestlers.¹  These contrasting data are similar to those for the BJJ fighters in our report. The incidence of injury to the lower extremities also was greater in the more-experienced college-aged wrestlers.^1,13  Our assumption was that more experience would be related to a reduction in injury risk. However, our data analysis did not support this assumption, as the risk of joint injury was similar for belt ranks or experience levels during tournament competition.

Takedown maneuvers are the most common mechanisms of injury in high school and collegiate wrestling.⁹  Pasque and Hewett⁹  hypothesized that the takedown is a dangerous maneuver due to the defensive nature of the position. Although we did not capture data on injury mechanism, the lack of differences among belt levels or rank may suggest that mechanisms of injury are related more to inherent technique than skill in performing submission wrestling maneuvers. These data suggest that it may be possible to reduce the chance of injury by increasing awareness by and further educating referees, athletes, and mentors and instructors (the latter 2 in particular with respect to defensive-position coaching).⁹  In future studies of injury incidence in BJJ, researchers ought to include mechanisms of injury to support the development of detailed injury-prevention programs.

Yard et al¹³  indicated that injuries were common at both the high school and collegiate levels of wrestling competition, but the rate of injury increased for the more experienced wrestlers. Collegiate wrestlers sustained higher injury rates and more severe injuries as competition experience levels increased. In addition, injury rates were 3 times higher in collegiate than high school wrestlers.¹³ 

Injury data for athletes in combat sports similar to BJJ, such as judo, have indicated an increased frequency of injuries in the upper extremities.^6,16,17  Injuries in judo-style competition occur most often from grip fighting, being thrown, or attempting to throw an athlete.^16,18–20  These outcomes are in contrast to data collected for BJJ fighters.

Although both BJJ and judo are combative sports, data suggesting cervical injury is prevalent in competition are limited.^{16–18,20,21}  Concurrently, researchers^1,15,22,23  have reported that collegiate athletes in wrestling competitions and practice sessions experienced fewer cervical injuries than overall extremity injuries. Whereas wrestling-style arts and judo share features with MMA, the former do not include deliberate striking during practice and competitions, as MMA-style competition does. This dichotomy may lead to increased rates of facial and head injuries in MMA competitions.^2–5,24,25 

A stark difference between collegiate wresting and BJJ grappling is the ability of BJJ fighters to submit opponents via a joint neck choke or joint lock (ie, taking a joint to its terminal end range to finish a match). Collegiate wrestling rules do not allow such joint locks to subdue an opponent. As noted, we did not collect data about the mechanism of injury during this study; however, during our medical staff coverage of BJJ over the past 10 years, we consistently have observed that joint location of injury and its applied joint locks reflect terminal end range of the applied lock. During this study, BJJ injuries were reported as athletes requesting medical treatment or being unable to continue a contest due to pain or discomfort.

Although in its infancy in the United States, BJJ is similar to collegiate wrestling because the participants have similar injury rates and locations of injury when compared by skill level. We postulate that higher-level fighters may have increased injury rates because rules allow competitors at the brown belt and black belt levels (but not at the blue belt and purple belt levels) to attack the lower extremities. Concomitantly, more-experienced fighters may attempt to withstand the potential submission hold due to their experience levels and knowledge of the position. However, given that no data have been reported on these characteristics, future studies are recommended to elucidate these experience factors and rates of injury.

To our knowledge, we are the first to study the musculoskeletal joint injuries at a large BJJ-style championship event. These large events have increased markedly in frequency and location throughout the United States in the past decade.⁸  Thus, the understanding of BJJ and its potential injuries is warranted as the sport continues to grow. Additional strengths of our study are the prospective research design and the medical team's combined 27 years of experience covering the sport of BJJ and observing injuries in its competitors.

Our study had some limitations. First, the definition of injury may vary by study. Our definition reflected any athlete who requested medical treatment during the tournament or who could not continue due to pain or discomfort. Second, whereas the injury mechanism may be synonymous with terminal joint end range, data were not recorded due to multiple possible injury mechanisms. Other researchers^1,13  have discussed injuries as resulting in time missed from participation after a practice or event. In this study, we were unable to capture all injuries resulting in time missed from participation after an event for several reasons.¹  Self-reporting of injuries during the tournament was voluntary. Our medical staff, event referees, and others did their best to identify all competitors perceived to have incurred injuries and recommend that they report to the medical tent during the event; however, it is possible that some athletes still decided not to report their injuries. Last, data for this event were collected only for athletes known to be injured during the competition. A small possibility exists that injuries to joints were not reported to the medical area; however, the proximity of the medical area to competition helped ensure that most reportable joint injuries were captured.

The total injury rates for the World Jiu-Jitsu No-Gi Championship 2009 were similar in joint location and frequency to rates for National Collegiate Athletic Association wrestlers. We found a trend toward athletes at more experienced levels having higher risks of injury. Although speculative, assumptions for increased injury rates at higher belt levels may have been due to a difference in rules among the levels. Last, the elbow and knee joints had higher injury rates than the shoulder and ankle joints.

Based on limited published studies, to our knowledge, no data about the injury incidence in BJJ have been reported. Future research is warranted to determine mechanisms of injury and risk factors in BJJ. Investigators should focus on mapping specific injury patterns. As the number of BJJ competitions continues to increase worldwide, a better understanding of injury frequency and type should be of primary concern. Based on the injury rates and severities we observed, we highly recommend efforts to include qualified sports medicine personnel at all BJJ events for improved prevention, recognition, and treatment of injuries.