Ankle proprioception is not targeted by exercises on an unstable surface

Area of Science:

• Biomechanics
• Neuroscience
• Sports Medicine

Background:

• Lateral ankle sprain (LAS) has high recurrence rates (>70%) often linked to impaired ankle proprioception.
• Rehabilitation for LAS frequently employs balance exercises on unstable surfaces to enhance proprioception.

Purpose of the Study:

• To investigate whether exercises on unstable surfaces effectively target ankle proprioception.
• To determine the impact of surface stability on proprioceptive feedback during balance tasks.

Main Methods:

• A repeated measures design study involving 100 healthy adults.
• Participants stood barefoot on solid and foam surfaces over a force plate with eyes occluded.
• Muscle vibration (triceps surae and lumbar paraspinal) was applied to assess proprioceptive responses via center of pressure (CoP) analysis.

Main Results:

• Vibration of the triceps surae had a smaller effect on CoP velocity and displacement on foam compared to a solid surface.
• Vibration of paraspinal muscles showed a greater effect on CoP measures on foam than on a solid surface.
• Findings indicate reduced peripheral ankle proprioception targeting on unstable surfaces.

Conclusions:

• Exercises on unstable surfaces may not specifically target peripheral ankle proprioception.
• These exercises might instead challenge the central nervous system's ability to reweight proprioceptive inputs for balance control.