J Athl Train. 2023 Aug 30. doi: 10.4085/1062-6050-0014.23. Online ahead of print.
CONTEXT: The neurocognitive health effects of repetitive head impacts have been examined in many sports. However, a paucity of head impact characterization exists for sliding sport athletes.
OBJECTIVE: To describe head impact kinematics and injury epidemiology in elite athletes during the 2021-2022 Bobsleigh World Cup season.
DESIGN: Cross-sectional study.
SETTING: On-track training and competitions during the Bobsleigh World Cup season.
PARTICIPANTS: Twelve elite bobsleigh athletes (3 pilots (1 female), 9 push athletes (5 females); 30±5y; Female: 173±8cm, 75±5kg; Male: 183±5cm, 101±5kg).
MAIN OUTCOMES: Athletes wore an accelerometer-enabled mouthguard to quantify six-degree-of-freedom head impact kinematics. Isometric absolute and relative neck strength, number of head acceleration events (HAE), workload (J), peak linear velocity (PLV; m·s-1), peak angular velocity (PAV; rad·s-1), peak linear acceleration (PLA; g), and peak angular acceleration (PAA; rad·s-2) were derived from mouthguard manufacturer algorithms. Linear mixed-effect models tested the effect of sex (male vs. female), setting (training vs. competition), and position (pilot vs. push athlete) on kinematic variables.
RESULTS: 1900 HAEs were recorded over 48 training and 53 competition days. There were no differences between the number of HAEs per run per athlete by sex (IRR=0.82, p=0.741), setting (IRR=0.94, p=0.325), or position (IRR=1.64, p=0.463). No sex differences were observed for workload (mean±standard deviation: males=3.3±2.2J, females=3.1±1.9J, p=0.646), PLV (males=1.1±0.3m·s-1, females=1.1±0.3m·s-1, p=0.706), PAV (males=4.2±2.1rad·s-1, females=4.7±2.5rad·s-1, p=0.220), PLA (male=12.4±3.9g, females=11.9±3.5g, p=0.772), or PAA (males=610±353rad·s-2, females=680±423rad·s-2, p=0.547). There were also no effects of setting or position on any kinematic variables. Male athletes had greater peak neck strength than female athletes for all neck movements, aside from right-side flexion (p = 0.085), but no sex differences were observed in relative neck strength.
CONCLUSION: This work provides a foundational understanding of the repetitive HAEs that occur in bobsleigh athletes. Future work should determine the effects of repetitive head impacts on neurocognitive function and mental health.