Long-Term Cumulative Effects of Repeated Concussions in Cyclists

Background/Objectives: Sports related concussion (SRC) is mostly associated with contact and combat sports. However, emerging evidence suggest that cyclists are also at risk of repeated concussion injury. Moreover, long-term neurophysiological outcomes in cycling cohorts remain underexplored. This novel study aimed to investigate in cyclists (in-cluding road, mountain biking [MTB], and BMX) with a history of concussion and self-reported persistent symptoms demonstrate alterations in neurophysiology and cog-nitive-motor performance compared to previously concussed cyclists with no ongoing symptoms and age-matched controls. Methods: Twenty-five cyclists with a history of concussions (15 symptomatic, 10 asymptomatic) and 20 controls completed symptom reporting, cognitive and balance assessments (SCAT5), sensorimotor testing using vi-brotactile stimulation, and neurophysiological assessment vis transcranial magnetic stimulation (TMS). Results: Symptomatic cyclists reported a higher number of concussions compared to asymptomatic cyclists (p=0.041). Cognitive testing revealed impaired con-centration in symptomatic cyclists compared to controls (p=0.005). Motor assessments demonstrated slower tandem gait times (p< 0.001) and more errors (p=0.02) in the symptomatic group. Sensorimotor testing indicated slowed simple reaction times (p=0.001) and poorer temporal order judgement (p=0.038). TMS showed increased cortical inhibition in the symptomatic group, with prolong cortical silent periods (p< 0.05) and reduced short interval intracortical inhibition (p=0.001) compared to asymptomatic cyclists and controls. Conclusions: Cyclists reporting persistent symptoms showed greater cortical inhibition and impaired cognitive-motor performance, consistent with findings in contact-sport athletes. These results suggest that repeated concussions in cycling carry risk of chronic neurophysiological alterations. Cycling disciplines should consider more rigorous con-cussion identification protocols and stricter management strategies to mitigate persistent and long-term consequences.