To evaluate the self-reported history of concussion in athletes of both Brazilian Jiu-Jitsu (BJJ) and Muay Thai.

Combat sports are widely practiced around the world. They include modalities that involves punches or kicks directed at the opponent's head (Striking sports) or that consists of grabbing an opponent and taking him to the ground (Grappling sports). Due to the objectives and close contact in combat sports, the risk of concussion is significant.

Among BJJ athletes, 61% reported a history of concussion, while among Muay Thai athletes the percentage was more higher (86%). The main mechanisms of head impact were the throw/takedown and elbow-hits to the head in BJJ and punches and knee-hits to the head in Muay Thai. There was no difference in the symptom score between BJJ and Muay Thai concussed athletes (average of 11 vs 10.7, respectively). The most common symptoms were dizziness, headache and nausea in BJJ athletes, and headache, nausea, drowsiness and brain fogginess in Muay Thai ones.

The results presented herein suggest that concussions in Muay Thai and BJJ occur through different mechanisms. The clinical profile of post-concussion symptoms appears to be different between BJJ and Muay Thai athletes.