Head Kinematics and Injury Analysis in Elite Bobsleigh Athletes Throughout a World Cup Tour.

Abstract

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. To describe head impact kinematics and injury epidemiology in elite athletes during the 2021-2022 Bobsleigh World Cup season. Cross-sectional study. On-track training and competitions during the Bobsleigh World Cup season. 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). 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. 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. 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.