Kabir Singh Lota: Barts and The London School of Medicine and Dentistry, London, E1 2AD, UK. ORCID
Nikos Malliaropoulos: Centre for Sports and Exercise Medicine, Queen Mary University of London, E1 4DG, UK.
Wiesław Blach: Department of Physical Education and Sport, University School of Physical Education, Wrocław 51-612, Poland.
Takeshi Kamitani: School of Sport and Health Science, Tokai Gakuen University, 21-233 Nishinohora, Ukigai, Miyoshi, Aichi, 470-0207, Japan.
Akira Ikumi: Department of Orthopedic Surgery and Sports Medicine, Tsukuba University Hospital Mito Clinical Education and Training Center, 3-2-7 Miyamachi, Mito, Ibaraki 310-0015, Japan.
Vasileios Korakakis: Aspetar Orthopaedic and Sports Medicine Hospital, 29222, Doha, Qatar.
Nicola Maffulli: Centre for Sports and Exercise Medicine, Queen Mary University of London, E1 4DG, UK.
BACKGROUND: Traumatic brain injury (TBI) in combat sports is relatively common, and rotational acceleration (RA) is a strong biomechanical predictor of TBI. This review summarizes RA values generated from head impacts in combat sport and puts them in the context of present evidence regarding TBI thresholds. SOURCES OF DATA: PubMed, EMBASE, Web of Science, Cochrane Library and Scopus were searched from inception to 31st December 2021. Twenty-two studies presenting RA data from head impacts across boxing, taekwondo, judo, wrestling and MMA were included. The AXIS tool was used to assess the quality of studies. AREAS OF AGREEMENT: RA was greater following direct head strikes compared to being thrown or taken down. RA from throws and takedowns was mostly below reported injury thresholds. Injury thresholds must not be used in the absence of clinical assessment when TBI is suspected. Athletes displaying signs or symptoms of TBI must be removed from play and medically evaluated immediately. AREAS OF CONTROVERSY: Methodological heterogeneity made it difficult to develop sport-specific conclusions. The role of headgear in certain striking sports remains contentious. GROWING POINTS: RA can be used to suggest and assess the effect of safety changes in combat sports. Gradual loading of training activities based on RA may be considered when planning sessions. Governing bodies must continue to work to minimize RA generated from head impacts. AREAS TIMELY FOR DEVELOPING RESEARCH: Prospective research collecting real-time RA data is required to further understanding of TBI in combat sports.
