Relationship Between Functional Ankle Instability and Postural Control (original) (raw)
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Australian Journal of Physiotherapy, 2007
Questions: Is loss of proprioception or loss of motor control related to functional ankle instability? Are proprioception and motor control related? Is there any difference in proprioception or motor control between ankles with different severity of functional ankle instability? Design: Cross-sectional, observational study. Participants: Twenty people aged between 18 and 40 years with functional ankle instability associated with a history of ankle sprain more than one month prior. Twenty age-matched controls with no functional ankle instability or history of ankle sprain. Outcome measures: Functional ankle instability was classified using the Cumberland Ankle Instability Tool, proprioception at the ankle was measured as movement detection at three velocities, and motor control was measured using the Landing Test and the Hopping Test. Results: There was little if any relation between proprioception (r = -0.14 to -0.03, 95% CI -0.40 to 0.25) or motor control (r = -0.08 to -0.07, 95% CI -0.35 to 0.20) and functional ankle instability. There was also little if any relation between proprioception and motor control except for a low correlation between movement detection at 0.1 deg/s and the Landing Test (r = 0.35, 95% CI 0.09 to 0.58). Furthermore, there was no difference between the ankles with or without functional ankle instability in proprioception or motor control. Conclusion: By greater than one month after ankle sprain, loss of proprioception does not make a major contribution to functional ankle instability. [de Noronha M, Refshauge KM, Kilbreath SL, Crosbie J (2007) Loss of proprioception or motor control is not related to functional ankle instability: an observational study. Australian Journal of Physiotherapy 53: 193-198]
Journal of athletic training, 1997
The purpose of this study was to determine if individuals with unilateral functional ankle instability had decreased ability to maintain postural sway, as well as decreased isokinetic eccentric strength of ankle evertors and invertors. SUBJECTS WITH NO PREVIOUS HISTORY OF ANKLE INJURY WERE COMPARED WITH SUBJECTS WITH FUNCTIONAL ANKLE INSTABILITY ON THE FOLLOWING TESTS: isokinetic eccentric inversion and eversion strength and measures of single-limb postural sway. EIGHTEEN SUBJECTS PARTICIPATED IN THIS STUDY: 9 subjects in the functional instability (FI) group (age = 22.89 +/- 3.18 yr, ht = 181 +/- 6.0 cm, wt = 80.25 +/- 12.2 kg) and 9 noninjured (NI) controls (age = 26.22 +/- 2.34 yr, ht = 170 +/- 10.0 cm, wt = 65.08 +/- 12.03 kg). Subjects performed postural sway assessment on a balance system under static and dynamic conditions. Ankle inversion and eversion eccentric strength were evaluated at 90 degrees /sec using an isokinetic dynamometer. Additionally, we assessed the degree of...
Commentary: Functional Ankle Instability Revisited
Journal of athletic training, 2002
hronic ankle instability is a clinical problem frequently seen in athletes. Various complicated mechanical and neuromuscular factors seem to be involved in chronic ankle instability. The purpose of this special communication is to revisit the concept of functional ankle instability and to discuss its clinical relevance. The 2 hypothesized causes of chronic ankle instability have been labelled mechanical instability and functional instability. Mechanical instability (MI) is defined as ankle movement beyond the physiologic limit of the ankle's range of motion. The term ''laxity'' is often used synonymously with MI. Functional instability (FI) is defined as the subjective feeling of ankle instability or recurrent, symptomatic ankle sprains (or both) due to proprioceptive and neuromuscular deficits. FUNCTIONAL BIOMECHANICS OF ANKLE INSTABILITY
Dynamic Postural Stability Deficits in Subjects with Self-Reported Ankle Instability
Medicine & Science in Sports & Exercise, 2007
Purpose: A limited understanding of how functional ankle instability (FAI) affects dynamic postural stability exists because of a lack of reliable and valid measures. Therefore, the purpose of this investigation was to determine whether a new reliable index for dynamic postural stability could differentiate between those with stable ankles and those with FAI. Methods: Data were collected on 108 subjects (54 subjects with stable ankles (STABLE group); 54 subjects with functionally unstable ankles (FAI group)). Subjects performed a single-leg-hop stabilization maneuver in which they stood 70 cm from the center of a force plate, jumped off both legs, touched a designated marker placed at a height equivalent to 50% of their maximum vertical leap, and landed on a single leg. The dynamic postural stability index and directional stability indices (medial/lateral, anterior/posterior, and vertical) were calculated. The raw and normalized (to energy dissipated) indices were compared between groups. Results: Significant differences were noted for the anterior/posterior stability index (FAI = 0.36 T 0.09, STABLE = 0.30 T 0.06). Similar results were seen for the vertical stability index (FAI = 0.73 T 0.17, STABLE = 0.61 T 0.13), the normalized dynamic postural stability index (FAI = 0.85 T 0.17, STABLE = 0.73 T 0.12), the normalized vertical stability index (FAI = 0.007 T 0.004, STABLE = 0.005 T 0.001), and the dynamic postural stability index (FAI = 0.008 T 0.003, STABLE = 0.006 T 0.001). Conclusions: These results indicate that the dynamic postural stability index is a sensitive measure of dynamic postural stability and is capable of detecting differences between individuals with stable ankles and individuals with functionally unstable ankles.
Chronic Ankle Instability Does Not Affect Lower Extremity Functional Performance
Journal of athletic training, 2002
OBJECTIVE: To determine if functional performance is impaired in individuals with self-reported chronic ankle instability. DESIGN AND SETTING: We used a between-groups design to assess 3 functional variables. All data were collected at a Division III college and a military academy. Before testing, all subjects performed a 5-minute warm-up, followed by a series of stretches for the lower extremity muscles. Subjects then performed cocontraction, shuttle run, and agility hop tests in a counterbalanced fashion. Three trials for each functional test were completed and averaged for analysis. SUBJECTS: Twenty men with a history of at least 1 significant ankle sprain and episodes of at least 1 repeated ankle injury or feelings of instability or "giving way" were compared with 20 men with no prior history of ankle injury. Subjects were matched by age, height, weight, and activity level. MEASUREMENTS: Time to completion was measured in seconds for the cocontraction and the shuttle r...
Mechanical stability, muscle strength and proprioception in the functionally unstable ankle
Australian Journal of Physiotherapy, 1994
Functional instability of the ankle is common following inversion sprain. Factors suggested as causes of this disability include mechanical instabilityofthetalocrural joint, peroneal muscle weakness and motor incoordination due to impaired proprioception. This study documented physical examination characteristics of functionally unstable ankles relevant to these theories. Each ankle of 45 subjects with unilateral functional instability was examined. Mechanical stability was assessed by standard clinical instability tests. Evertor and invertor muscle strength was measured using the Cybex II dynamometer. The Uni-axial Balance Evaluator (UBE) was used to assess dynamic control ofthe ankle and was considered capab:a of detecting unilaterally impaired proprioception. Mechanical instability was frequently absent in the functionally unstable ankles tested. Evertor muscle strength was similar in the normal and functionally unstable ankles. UBE results were consistent with the theory of impaired proprioception contributing to functional instability, but the need for further research is emphasised. [Ryan LG: Mechanical stability, muscle strength and proprioception in the functionally unstable ankle.
The effects of functional instability of the ankle joint on balance
Physiotherapy Practice and Research, 2015
Background: Individuals who suffer from ankle instability may experience restricted movement and a weakening of the muscles that support the ankle. Purpose: The aim of this study was to investigate the effects of functional instability of the ankle joint on static and dynamic balance performances. Basic Methods Twenty-five participants (8 male, 17 female) were recruited for this study. The subjects were divided into two groups: an ankle instability and a normal ankle stability group. The static and dynamic limits of stability performance were assessed in single leg standing using the BioRescue device. In addition, the Functional Reach Test (FRT) and the Modified Functional Reach Test (MFRT) were also recorded. Main Results Significant differences between the two groups were found in the moving distance and the mean velocity of the center of pressure during the single leg standing test, the pendular limits of stability test, and the MFRT. However, the FRT showed no significant difference between the two groups. The results showed that the static and dynamic balance performances were reduced in the ankle instability group compared with the control group. Principal Conclusion Both the MFRT and BioRescue were sensitive and appropriate to pick clinically important differences between the two groups. The use of the MFRT is a quick and inexpensive clinical 3 measure of postural instability relevant to individuals with ankle instability. Further studies should use the MFRT to determine the effectiveness of clinical interventions for ankle instability that target improvements in balance.