Vertigo in downhill mountain biking and road cycling

A New Perspective to Interpret How the Vestibular Efferent System Correlates the Complexity of Routine Balance Maintenance with Management of Emergency Fall Prevention Strategies

Bipedalism is unique among mammals. Until modern times, a fall and resulting leg fracture could be fatal. Balance maintenance after a destabilizing event requires instantaneous decision making. The vestibular system plays an essential role in this process, initiating an emergency response. The afferent otolithic neural response is the first directionally oriented information to reach the cortex, and it can then be used to initiate an appropriate protective response. Some vestibular efferent axons feed directly into type I vestibular hair cells. This allows for rapid vestibular feedback via the striated organelle (STO), which has been largely ignored in most texts. We propose that this structure is essential in emergency fall prevention, and also that the system of sensory detection and resultant motor response works by having efferent movement information simultaneously transmitted to the maculae with the movement commands. This results in the otolithic membrane positioning itself precisely for the planned movement, and any error is due to an unexpected external cause. Error is fed back via the vestibular afferent system. The efferent system causes macular otolithic membrane movement through the STO, which occurs simultaneously with the initiating motor command. As a result, no vestibular afferent activity occurs unless an error must be dealt with.

[Current trends and injuries in cycling: faster, further, e-bike?]

During the past decade, technical innovations (e.g., carbon as a new material, disk brakes, hydraulic shock absorbers, electric transmissions) and lifestyle changes have significantly influenced recreational and professional cycling. In contrast to the past, where ambitious leisure cyclists were primarily interested in the recreational value of nature and landscape, cyclists of all ages are nowadays increasingly focused on performance and self-optimization. Simultaneously, manufacturers have adapted to differing customer requirements: besides the traditional extremities of road and mountain bikes, many specialized models have been designed for special applications: trekking, cyclocross, gravel, full-suspension, single-track, hardtail, downhill, fatbike, etc. For biking fans who are no longer able to meet their own demands due to individual physical restrictions or defined health problems, electric-assist bikes (pedelecs or "e-bikes") were recently introduced. While these are becoming increasingly popular, they have also increased the number of accidents and injuries. The current work provides an update on relevant sport medical and orthopaedic challenges brought on by these developments in cycling.