Force sense deficits in functionally unstable ankles.

Area of Science:

• Biomechanics
• Motor Control
• Sports Medicine

Background:

• Functional ankle instability (FAI) is a common condition following ankle sprains.
• FAI is characterized by recurrent episodes of giving way and perceived joint instability.
• Proprioceptive deficits, including impaired joint position sense, are often associated with FAI.

Purpose of the Study:

• To investigate force sense reproduction deficits in individuals with FAI compared to healthy controls.
• To determine if FAI is associated with impaired ability to accurately reproduce a specific ankle eversion force.

Main Methods:

• Twenty participants with FAI and 20 healthy controls performed ankle force sense testing.
• Participants reproduced submaximal eversion isometric contractions at 10%, 20%, and 30% of their maximal voluntary contraction.
• Absolute error and variable error were calculated to quantify force reproduction accuracy.

Main Results:

• Participants with FAI demonstrated significantly greater absolute error in force reproduction compared to controls (3.7 N vs. 2.8 N).
• Variable error was also significantly higher in the FAI group, indicating less consistent force reproduction (3.2 N vs. 2.4 N).
• These differences were statistically significant (p < 0.05).

Conclusions:

• Functional ankle instability is linked to deficits in the ability to accurately sense and reproduce ankle joint forces.
• Impaired force sense may compromise the neuromuscular system's capacity to generate appropriate muscle forces for joint stabilization.
• These findings suggest that interventions targeting sensory-motor deficits could be beneficial for managing FAI.