Postural control differs between those with and without chronic ankle instability.

Biodynamics Research Laboratory, Department of Kinesiology, University of North Carolina at Charlotte, Charlotte, NC 28223,United States.
Gait & posture (Impact Factor: 2.58). 04/2010; 32(1):82-6. DOI: 10.1016/j.gaitpost.2010.03.015
Source: PubMed

ABSTRACT Despite a history of a lateral ankle sprain, some individuals (copers) return to high-level activities (i.e. jumping, pivoting) without recurrent injury or loss of function while others develop chronic ankle instability (CAI). Understanding the differences between these groups may provide insight into the mechanisms of CAI. The objectives of this investigation were to: (1) compare traditional center of pressure [COP], time-to-boundary [TTB], and center of pressure-center of mass [COP-COM] moment arm measures of postural control among controls, established copers, and subjects with CAI and (2) determine the accuracy of these postural control measures at discriminating between established copers and subjects with CAI using receiving operating characteristic curves. 48 subjects (control=16, coper=16, CAI=16) completed two, 30-s trials of single-leg stance on a force plate with their eyes open. Coper and CAI subjects stood on their involved limb while controls stood on a matched limb. The results indicated that mediolateral (p<0.01) and anteroposterior (p<0.01) COP velocity was greater in individuals with CAI relative to both copers and controls. Similarly, the peak COP-COM moment arm in the anteroposterior direction (p<0.01) and the resultant mean COP-COM moment arm (p<0.01) were increased in individuals with CAI relative to copers. These measures also reached asymptotic significance (p<0.05) indicating that they successfully discriminated between established copers and individuals with CAI.

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    ABSTRACT: Individuals with chronic ankle instability (CAI) usually experience deficits in balance control, which increase displacement in the body's center of pressure (COP) when they balance on a single leg. Little is known, however, about whether or not these individuals use the strategies of postural adjustment properly, especially during functional tasks that may predispose them to ankle sprain. The aim of this study was to investigate anticipatory (APA) and compensatory (CPA) postural adjustments in individuals with and without CAI as they kick a ball while standing in a single-leg stance with their ankle in neutral and supinated positions. COP displacements were calculated and their magnitudes (range) analyzed during APA and CPA intervals and over the duration of the whole task, represented by the COP area of sway and mean velocity. The CAI group exhibited a significant decrease in CPA and area of sway over the whole task, relative to controls. These results suggest that the decreased balance sway could be caused by the need for further stabilization of the ankle in more unstable postures to prevent recurrent sprain. Our findings could help clinicians to better understand the strategies of postural adjustments in individuals with CAI, and may assist and motivate new investigations into balance control interventions in such individuals, as well as proactively address recurrent ankle sprain conditions.
    Gait & posture 01/2014; · 2.58 Impact Factor
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    ABSTRACT: [Purpose] This study aimed to validate the postural control characteristics of individuals with a history of ankle sprain during single leg standing by using a gravicorder and head and foot accelerometry. [Subjects] Twenty subjects with and 23 subjects without a history of ankle sprain (sprain and control groups, respectively) participated. [Methods] The anteroposterior, mediolateral, and total path lengths, as well as root mean square (RMS) of each length, were calculated using the gravicorder. The anteroposterior, mediolateral, and resultant acceleration of the head and foot were measured using accelerometers and were evaluated as the ratio of the acceleration of the head to the foot. [Results] There was no significant difference between the two groups in path length or RMS acceleration of the head and foot. However, the ratios of the mediolateral and resultant components were significantly higher in the sprain group than in the control group. [Conclusion] Our findings suggest that individuals with a history of ankle sprain have a higher head-to-foot acceleration ratio and different postural control characteristics than those of control subjects.
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Jun 5, 2014