Spinal and Supraspinal Control in Chronic Ankle Instability

Condition(s) studied

Investigational drug(s) / intervention(s)

The structured balance training protocol: The structured balance training protocol consists of 7 exercises including balance and hop stabilization exercises for athletes with chronic ankle instability.

Study summary

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.

Eligibility

Primary outcome measure(s)

• Proprioceptive-Stabilometric Assessment — at the baseline and end of the intervention, 8 weeks
  The Prokin PK 252 will be used for proprioceptive-stabilometric assessment of the lower extremities, incorporating static and dynamic evaluations. The sensorimotor assessment will include the monopodal controlled-load proprioceptive control test and its variant with total load. Participants will perform movements with one foot on the platform, with angular displacements converted into electrical impulses for data acquisition. Static balance will be assessed on a stable platform for 30 seconds per ankle under eyes-open and eyes-closed conditions. Dynamic balance will be measured on an unstable platform under the same conditions. Proprioception will be evaluated on an unstable platform for 90 seconds, guiding the platform through horizontal, diagonal, and circular patterns as per the test program.
• Transcranial Magnetic Stimulation — at the baseline and end of the intervention, 8 weeks
  Transcranial Magnetic Stimulation (TMS), a non-invasive neurophysiological technique, will be used to assess motor cortical function. Corticomotor excitability will be evaluated using dual-cone coil TMS to examine adaptations following cross-training after unilateral training. TMS will induce corticospinal volleys of direct (D) and indirect (I) waves. The resting motor threshold (rMT), a biomarker of upper motor neuron function, will be recorded. EMG recordings will assess corticomotor excitability, with Ag/AgCl electrodes placed on the tibialis anterior, peroneus longus, and gastrocnemius medialis muscles, following SENIAM guidelines. Participants will be seated in a TMS chair, and the hotspot in the left primary motor cortex will be identified. The MEP amplitude will be assessed at 120% rMT with 10 repetitions, and latency will be recorded. A 15-minute rest will be observed between muscle tests.
• Hoffman Reflex — at the baseline and end of the intervention, 8 weeks
  The H-reflex will be measured to assess motor neuron pool excitability within the spinal loop, aiming to explain the mechanism underlying bilateral adaptations. As a valuable tool for evaluating neurological function in athletes, the H-reflex will provide insights into neurophysiological changes. EMG signals will be pre-amplified and bandpass filtered between 30-300 Hz and recorded from the peroneus longus, tibialis anterior, and gastrocnemius medialis muscles. The tibial nerve will be stimulated using single 1 ms square-wave pulses applied over the popliteal fossa. The test sequence will be randomized between stable and unstable ankles, ensuring balanced measurements. H-reflex excitability will be assessed for both ankles before and after the protocol to determine neuromuscular adaptations.

Trial sites (2)

Other trials for the same condition