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Evaluating Postural Control and Lower-extremity Muscle Activation in Individuals with Chronic Ankle Instability
Published on: September 18, 2020
Peroneal activation deficits in persons with functional ankle instability.
Riann M Palmieri-Smith1, J Ty Hopkins, Tyler N Brown
1School of Kinesiology, University of Michigan, 401 Washtenaw Avenue, Ann Arbor, MI 48109, USA. riannp@umich.edu
The American Journal of Sports Medicine
|March 10, 2009
Summary
Functional ankle instability (FAI) involves arthrogenic muscle inhibition (AMI) in peroneal muscles, but this inhibition doesn't directly impact dynamic muscle activity. Restoring dynamic peroneal activation is key for ankle stabilization.
Area of Science:
- Orthopedics
- Sports Medicine
- Neuromuscular Physiology
Background:
- Functional ankle instability (FAI) affects up to 40% of individuals post-acute lateral ankle sprain.
- Damaged mechanoreceptors can cause arthrogenic muscle inhibition (AMI), leading to peroneal muscle activation deficits and FAI.
- Inadequate muscle activation compromises ankle joint control, increasing susceptibility to recurrent instability.
Purpose of the Study:
- To investigate the presence of arthrogenic muscle inhibition (AMI) in the peroneal musculature of individuals with functional ankle instability (FAI).
- To determine the relationship between AMI and dynamic peroneal muscle activity during a sudden ankle inversion perturbation.
Main Methods:
- A cross-sectional study involving 21 patients with unilateral FAI and 21 matched controls.
- Bilateral recording of peroneal maximum H-reflexes and M-waves to assess AMI via H:M ratios.
- Electromyography (EMG) quantified dynamic peroneal muscle activation during a simulated ankle inversion perturbation during walking.
Main Results:
- Patients with FAI exhibited significantly higher peroneal H:M ratios in their non-pathological ankle compared to their pathological ankle (P = .036).
- FAI patients demonstrated significantly lower peroneal EMG activity after inversion perturbation in their pathological ankle compared to their uninjured ankle (P < .001).
- No significant correlation was found between the peroneal H:M ratio (AMI) and peroneal EMG amplitude (dynamic activation) (P > .05).
Conclusions:
- Arthrogenic muscle inhibition (AMI) is present in the peroneal muscles of individuals with FAI.
- AMI is not directly related to dynamic peroneal muscle activation levels as measured by EMG amplitude.
- Restoring dynamic peroneal muscle activation, rather than solely addressing AMI, is crucial for enhancing ankle stabilization and preventing recurrent instability.
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