Spinal and Supraspinal Control in Chronic Ankle Instability

Ankle sprains are common sports injuries that often lead to chronic ankle instability (CAI). Patients with CAI experience deficits in neuromuscular control (NMC), including proprioception and strength. It is believed that damage to the ankle's ligament mechanoreceptors and the peroneal nerve after the initial ankle sprain can cause alterations in NMC, resulting in postural control and dynamic joint stability dysfunction. Inflammation related to recurrent ankle sprains may also contribute to neuromuscular impairments. Evidence suggests that bilateral postural control deficits occur after an ankle sprain, suggesting alterations in the central nervous system (CNS). Rehabilitation for CAI has been shown to lead to bilateral improvements in NMC, potentially due to neural alterations at both the spinal and supraspinal levels. Cross-education, which refers to the muscular crossed effect of unilateral training, has also been proposed as a mechanism for improving contralateral strength in neurologically healthy individuals. While the exact mechanisms underlying cross-education are not yet fully understood, evidence suggests that it involves neural adaptations at both spinal and supraspinal levels. This study aims to investigate the cross-education effect of a 6-week, unilateral balance training on corticomotor excitability, motor neuron pool excitability, and static and dynamic balance in athletes with chronic ankle instability.