The effects of selected ankle appliances on postural control

Although ankle braces supposedly protect the ankle by providing mechanical support of the joint and enhancing proprioceptive input, their proprioceptive effects are unclear. Measuring the center of pressure during posture provides a reasonably well-controlled evaluation of proprioceptive input at the ankle. We, therefore, compared the changes in the center of pressure resulting from wearing ankle braces and wearing no brace (control).

Center-of-pressure variables were measured during a one-legged modified Romberg test with six variations. The six test conditions systematically altered the three sensory modalities that control posture: visual input, vestibular input, and proprioceptive input. Subjects performed three 16-second trials of each Romberg variation for each brace condition.

Twenty-four male volunteers (age = 18 to 26 yr) with no history of ankle injuries in the past 5 years and no difficulty with balance.

Center of pressure, transmitted through the bottom of the foot, was monitored during each trial and transformed into total distance traveled, anterior-posterior (AP) position, and medial-lateral (ML) position.

Average AP and ML center-of-pressure positions were increased only during brace wearing when all sensory modalities were functioning normally (control condition). Total center-of-pressure distance was the same for all three brace conditions.

Our results do not support or refute the concept that bracing enhances proprioception. The fact that subjects relocated their center of pressure only during the control condition is perplexing. If braces were to enhance proprioception, one would expect to see lower average ML and average AP center-of-pressure values when comparing the braced with the unbraced conditions. Alternatively, the relocated position may represent a more stable position resulting from enhanced proprioception.