The Effect Of Three-Days Of Ankle Immobilization On Joint Motion And Neural Excitability

Boot immobilizers (BI) are commonly used following ankle injuries, however, little is known about the effects of prolonged usage on corticospinal and reflexive excitability, and on gait kinematics. A crossover design was implemented using twelve uninjured individuals (age:20.8±1.4 yrs, H:1.7±0.1 m, M:75.2±9.9 kg). Participants wore either a BI with a compression sock (CS), or just a CS for three days, with 7 days between conditions. Reflexive excitability changes (HMax:MMax ratio) were observed (F3,33=4.026; p=0.015), with significant decreases (p=0.003). For corticospinal excitability, changes were observed in resting motor threshold (F6,36=4.351; p=0.002), also with decreases (p=0.046). Significant changes were observed at the knee and hip in the frontal and transverse planes (p<0.05). Statistical parametric mapping analysis revealed significant main effects of time in knee frontal and transverse angles during stance (p<0.05). During swing, there were significant differences in knee sagittal and transverse angles (p<0.05), and hip transverse angles (p<0.05). Our results indicate that the BI increased corticospinal excitability and decreased reflexive excitability. In the context of injury, the former could be beneficial and the later, potentially problematic. We observed altered hip and knee mechanics, however, the long term effects remain unclear. Future studies are needed to determine effects in injured populations.