Downsides of downhill: The adverse effects of head vibration associated with downhill mountain biking on visuomotor and cognitive function

Exposure to whole body vibration (WBV) is experienced when the human body is supported by a vibrating surface. An emerging issue is related to the transference of WBV to the head that might be associated with changes in brain structure and function. Most studies investigating the effects of WBV examine the physiological and musculoskeletal effect, and relatively little attention has been given to vibration-induced cognitive problems.
In cycling, vibration is intrinsic to the activity due to the continuous interaction of the tyre surface and the terrain. Initial evidence of the negative effect of head vibration experienced in downhill mountain biking (DH MTB) has been presented by Hurst et al, 2020, who found that four DH trials were sufficient to impair aspects of executive function such as psychomotor speed, reaction time, processing accuracy, and mental flexibility. Although the study compared the DH group's performance to an exercise-matched group without head accelerations and a control group, the study lacked direct quantification of head accelerations. Nevertheless, the authors previously demonstrated that rotational and translational head accelerations during DH MTB are higher than those reported in soccer, snow sports, contact sports and BMX (Hurst et al., 2018). Provided that repetitive head accelerations could compromise white matter integrity and neurocognition over the course of a season in football and ice hockey, DH riders might face an increased risk of sustaining irreversible brain injuries over an entire race season. The primary aim of the PhD is to investigate how head vibrations associated with DH MTB influence cognitive function, oculomotor, and body movement control. A secondary aim is to elucidate the dose-response relationship between WBV and brain function. By gaining knowledge on the magnitude of head vibration and its potential influence on cognitive health, we can explore ways to reduce vibration and mitigate its harmful effect.