Motoneuron Function Does not Change Following Whole-Body Vibration in Individuals With Chronic Ankle Instability

Area of Science:

• Neuroscience
• Biomechanics
• Sports Medicine

Background:

• Chronic ankle instability (CAI) affects approximately 40% of individuals post-lateral ankle sprain, leading to recurrent injuries and instability.
• Deafferentation from mechanoreceptor damage may contribute to arthrogenic muscle inhibition (AMI) in CAI.
• Whole-body vibration (WBV) is explored for its potential to address neurophysiological deficits in CAI.

Purpose of the Study:

• To investigate the acute effects of a single bout of WBV on AMI and proprioception in individuals with CAI.
• To compare the responses of individuals with CAI to healthy controls following WBV.

Main Methods:

• A repeated-measures design was employed with 10 young adults with CAI and 10 healthy controls.
• Participants underwent control, sham, and WBV conditions in a randomized order.
• Assessment included soleus Hoffmann reflex (H-reflex) for AMI and ankle joint position sense for proprioception, measured pre-intervention, immediately post-intervention, and 30 minutes post-intervention.

Main Results:

• Soleus H-reflex:M-response ratios were significantly lower in the CAI group compared to controls, indicating the presence of AMI.
• No significant improvements in ankle joint position sense were observed in either group following the WBV intervention at 15° or 20° of inversion.
• Neither AMI nor proprioception showed improvement in the CAI group after an acute bout of WBV.

Conclusions:

• The study confirms the presence of arthrogenic muscle inhibition (AMI) in the affected limb of individuals with chronic ankle instability (CAI).
• An acute session of whole-body vibration (WBV) did not effectively reduce AMI or enhance proprioception in individuals with CAI.
• The findings suggest that a single WBV session is insufficient to ameliorate the neurophysiological deficits associated with CAI.