Abstract
Motorsport athletes are known for their remarkable driving skills, which require a complex interplay between cognitive and motor processes, particularly efficient visual performance and neck muscle function. The oculomotor system plays a critical role in the driver's visual perception and reaction time, accounting for at least 90% of the information drivers use. Meanwhile, neck muscle function is crucial in withstanding high gravitational forces (G-forces), maintaining postural stability, and head position. Although head and neck injuries remain a significant concern in motorsport, how oculomotor and neck muscle systems interact in motorsport athletes remains unclear, limiting our ability to develop targeted training to enhance performance, prevent injury, and ensure safety in high-speed environments. This thesis addresses that gap by exploring how these systems function in competitive automotive drivers compared to non-competitive automotive drivers.
The research began with a review of the literature on the biomechanical effect of head and neck support devices (HANS) and helmets in motorsport safety (Chapter 2) to identify research gaps. This systematic review found that while HANS and helmets significantly reduce biomechanical injury parameters, a notable gap exists in understanding their neuromechanical impacts on drivers, highlighting the need to investigate the underlying neuromechanical mechanisms contributing to head and neck injuries to enhance athlete safety. This was followed by a review of the literature on oculomotor and neck muscle function relevant to motorsport drivers (Chapter 3). The literature revealed that head and neck injuries can impair oculomotor performance and neck muscle function, yet these areas are under-researched in competitive automotive drivers. This review also informed the selection of appropriate tools for empirical studies to address these gaps. Building upon these findings, the original empirical studies were designed, as detailed in Chapter 4, to investigate the oculomotor performance of competitive automotive drivers and non-competitive automotive drivers (Chapter 5) and the anticipatory and compensatory head adjustments of competitive automotive drivers and non-competitive automotive drivers in response to side impact perturbations (Chapter 6).
In the first empirical study (Chapter 5), a preprogrammed virtual reality technology was used to measure and record baseline oculomotor performance in competitive automotive drivers and non-competitive automotive drivers, including the Active Visual Vestibulo-Ocular Reflex (VOR) in both horizontal and vertical orientations, anti-saccades, optokinetic nystagmus, saccades, smooth pursuit in both head-free and head-fixed conditions. Concurrently, neck muscle activity was measured using electromyography (EMG). In the second empirical study (Chapter 6), neck muscle activity and gaze behaviour were simultaneously recorded by EMG and the eye-tracker throughout the side-on impact test, along with different light stimulation as visual cues in standing and sitting positions in a custom-modified seat replicating the driving posture. Furthermore, the neck strength measures, the head-to-neutral relocation test (to evaluate proprioception), and the postural balance test were conducted to evaluate the baseline sensorimotor system.
In conclusion, the findings of the two empirical studies revealed that there were no significant differences between the groups in baseline oculomotor performance and neck muscle responses. This suggests that general assessments of oculomotor performance and neck muscle function may not capture competitive automotive drivers' specialised skills and adaptations, and/or that current training practices may not effectively enhance the measured variables. This highlights the need for more ecologically valid testing methods and targeted training programs focusing on task-specific abilities relevant to high-speed racing. However, distinct within-group neuromuscular control strategies were observed depending on the timing of visual stimuli and body posture during the perturbation protocol. These differences in neuromuscular control and visual response strategies influence the driver’s ability to anticipate and effectively manage impacts, highlighting a link between efficient oculomotor control, timely and appropriate neck muscle activation, and reduced injury risk. Specifically, inadequate or delayed neck muscle responses can increase head displacement and acceleration during impacts, potentially exacerbating the severity of injuries. Similarly, impaired oculomotor performance could delay hazard detection and reaction times, leading to less effective anticipatory muscle adjustments and higher injury risks. Visual cues are important in optimising these responses, with body position significantly affecting muscle activity efficiency. These findings suggest that environment and context may have a bigger effect on oculomotor and neck muscle function than general differences in driving experience or expertise.
By understanding the intricate interplay between oculomotor performance and neck muscle function, we might uncover opportunities to enhance motorsport safety and performance approaches. For instance, interventions designed to enhance oculomotor capabilities might contribute to quicker visual hazard recognition, enabling more timely anticipatory muscle activations. Likewise, training programmes targeting specific neck muscle groups and their anticipatory activation patterns could minimise head displacement and acceleration during crashes, directly reducing injury risk. Targeted interventions can be developed and tested to assess their effectiveness in helping athletes cope with impacts and reduce head and neck injury risks, especially during crashes or sudden impacts. Such insights might also lead to refinements in training methods that optimise neuromuscular responses and oculomotor control, thereby contributing to advancements in safety and performance strategies in motorsport.