Examining the Impact of Firearm Recoil During a Round of Trap Shooting on Neurometabolic Changes Associated With Traumatic Brain Injury

Abstract

The CDC identifies concussion as a blunt, blow, or jolt to the head resulting in brain injury. Shooting sports do not impose a direct blow to the head but instead inflict rapid acceleration to the brain via recoil transfer. Exposure to rapid, repetitive recoil may cause physiological disturbances in the brain, therefore resulting in mild traumatic brain injury (TBI). Chronic recoil transfer and overpressure exposure influencing neurometabolic changes of TBI have yet to be measured. The objective of this study was to examine kinetic energy experienced in trap and skeet shooters following one round of shooting in comparison to neurometabolic proteins to assess for TBI. Previous scientific evaluations of peripheral serum glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase-L1 (UCH-L1), and S100B show the proteins’ ability to indicate and measure severity of TBI and therefore, blood samples were obtained 30 minutes pre-shooting, then 30 minutes and 24 hours post-shooting for neurometabolic assessment in shooting sports. If recoil transfer interferes with neurometabolic function, the shooter may be susceptible to TBI. A total of eleven shooters were recruited in this study, with six shooter protein levels detectable for calculation (n = 6). Blood biomarker results revealed an increase in proteins GFAP (p = 0.131) and UCH-L1 (p = 0.034) pre-shooting versus 24 hours post-shooting, however GFAP values were not statistically significant. Participant demographics and GFAP comparisons demonstrate strong, positive correlation to age and body mass index (BMI) when compared to GFAP increase (r = 0.756, r = 0.835); UCH-L1 comparisons show a weak, positive correlation when compared to age and BMI (r = 0.165, r = 0.054). Further analysis suggested firearm recoil values kinetic energy (GFAAP r = -0.549, p = 0.039; UCH-L1 r = -0.715, p = 9.543e-7), force (GFAP r = -0.739, p = 0.119; UCH-L1 r = -0.893, p = 2.833e-6), and velocity (GFAP r = -0.524, p = 0.049; UCH-L1 r = -0.662, p = 2.387e-5) compared to neurometabolic protein increase 24 hours post-shooting yield a negative relationship and are not interrelated. Protein S100B was not analyzed due to testing error. In conclusion, this study promotes readily available blood analysis tools to diagnose TBI in sports. The study results contribute to the literature regarding research prognosis of TBI in all concussion-prone sports, military shooters, and in shooting sports. To further advance this research, larger bouts of shooting, measurement of additional neurometabolic proteins, and blast wave measurement following recoil should be observed to improve TBI observations in shooting sports.