Quantifying load in the head and neck region and its impact on long and short term head injuries in combat sports

INTRODUCTION: The goal of combat sports is to strike your opponent, and the most frequently struck area of the body is the head and neck region1. A career in combat sports means to be exposed to a large number of impacts to this area. With rising popularity, it becomes increasingly important to quantify forces applied to the athletes’ heads considering realistic conditions. These mechanisms are essential to understand better the cause of short and long-term traumatic brain injuries that may come from head impact exposure. The purpose of this systematic review is to further understand the current state of literature in the field of quantification of head impacts in combat sports. A more comprehensive cause-effect relationship insight is a prerequisite to preserve the athletes’ health.
METHODS: Six electronic databases were searched using a combination of specific keywords to find appropriate sources. Distinct inclusion/exclusion criteria were formulated to specify studies to be reviewed. The screening and study selection process was conducted with Rayyan2. Methodological quality was assessed using a modified checklist by Downs & Black (1998)3. Data extraction included experiment conditions, martial arts discipline, striking parts, load evaluation methodology and traumatic brain injury implications.
RESULTS: The study identification, quality assessment, and full-text screening yielded thirteen studies to be included in the final review (Table 1). Four studies (30%) involved human participants in live competition and six studies (46%) investigated human participants in controlled laboratory settings. Examiners utilized various forms of accelerometers and gyroscopes (46%), pressure and force sensors (15%) implemented in mouthguards, headgears, boxing gloves, a punching bag, a force plate and Hybrid III Dummy. Only two studies presented results considering 3D forces applied to the head following strikes in combat sports. Three articles were in silico studies simulating Von Mises stress (8%) and linear and rotational accelerations (23%) of the head as a result of strikes to the head.
DISCUSSION: Revealing important aspects in terms of load quantification in the head and neck region, current methodological approaches lack the ability to recreate the functional responses typical of a live human. In this regard, recorded data fails to distinguish links between movement and impact data to occurring injuries. The state of impact quantification is still in its infancy and thus full of unrealized potential. Given the complex biological nature of the head and brain, there is a heightened necessity for combat sports athletes to understand the consequences of impact to that area. Future research must seek to develop a deeper understanding of the entire brain and the interactions within possibly leading to the application of meaningful head impact data. Live competition studies show the closest depiction of the impacts and forces that occur to fighters and as such should be further explored compared to laboratory studies. This data can be supplemented using simulations to further comprehend and prevent the injuries that may occur after impact exposure to the head.
REFERENCES:
1. C Kirk; Hum Mov (2018)
2. Rayyan Systems Inc.; https://www.rayyan.ai
3. SH Downs, N. Black; J Epidemiol Community Health (1998)