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Background and aim: Chronic ankle instability (CAI) is a current disability that can affect on activity daily living of the patients. Many studies have indicated postural control deficits in these patients but the effect of a dual task on postural control has not been examined yet.

Materials and methods: Postural stability in CAI patients and healthy subjects was measured using the Force Plate. Eight positions concluded two different stances (double & single) with closed or opened eyes. All positions concurrently were done with a cognitive task. Anterior/posterior (Rfa) and medial/lateral (Rsw) mean sway quantified static postural stability.

Results: Mean sway significantly increased in patients in the anterior/posterior (single and double leg stance) and medial/lateral (single leg stance) directions (P<0.05). While performing a dual task anterior/posterior mean sway decreases within the patients group on the impaired leg stance (P<0.05). No difference is seen in the healthy subjects.

Conclusion: Postural control deficits were identified in participants with chronic ankle instability. In view of the fact that a cognitive task resulted in decreasing displacement of center of pressure in patients, this method may identify as an examination and a plan of treatment for affecting on ankle stabilizing factors.

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Background and aim: Knee osteoarthritis is one of the most common musculoskeletal problems, can affect on patient's daily activity and produce dependency in their daily activity and functional disability The aim of present study is to compare static balance in patients with knee osteoarthritis and healthy subjects using force plate. 

Materials & Methods: Postural stability in knee OA patients and healthy subjects (each group 20 subjects) were measured by force plate. Two positions were selected double stance with closed or opened eyes. Range of fore/aft (Rfa) and Range of side ways (Rsw), were measured as static postural stability.

Results: Rsw increased significantly in the double stance position in patients group (P<0.05). Also in both groups, Rsw and Rfa in the double stance with closed eyes were more than of open eyes position (P<0.05).

Conclusion: Postural control deficits and increase of center of pressure's sway were identified in participants with knee osteoarthritis. Therefore, one of the most important goals of rehabilitation is to improve balance control in knee OA patients.

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Background and Aim: Forces which applied to ankle joint for control of stability can cause damage to joint if it does not have suitable control. Chronic ankle instability (CAI) is a current disability that can affect on activity daily living of the patients. The aim of this study is to evaluate forces which contribute to control of posture in difficult conditions.

Material and Methods: Postural control was measured by force plate in two groups of CAI and healthy subjects. Eight positions were selected , including of double stances with closed or opened eyes, and single stances with opened eyes (right/ left) with and without a cognitive task. Force changes in two direction medial/lateral and anterior/posterior were evaluated with fractal time series analysis.

Results: Fractal dimension of force in two groups, following dual task in all of conditions reduced significantly (P<0.05). There was not significant different between two groups in double stance with or without dual task. Single stance in patients indicated significant increase of fractal dimension in affected ankle joint (P<0.05) but comparison of two side in healthy subjects did not have difference. Also there was significant increase of fractal in affected ankle joint of patients in comparison with similar side of healthy subjects (P<0.05).

Conclusion: Patients with (CAI) have a problem in regulation of force for control of posture. This difficulty increased and clearly indicated by dual task condition, which can cause susceptible qualifications for recurrent injuries. Fractal dimension is a suitable factor for analysis of control of posture in difficult situations.

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Background and Aim: Knee osteoarthritis is one of the most common musculoskeletal problems that can affect activity daily living of patients. Many studies have indicated postural control deficits in these patients but the effect of dual tasking on postural control has not been examined yet. The aim of this study is to investigat the effect of cognitive task on postural control in the female patients with knee osteoarthritis.
Materials and Methods: Postural stability in knee OA patients and healthy subjects (20 subjects in each group ) in four positions was measured using the Force plate. Positions included double leg stance with closed or opened eyes with and without cognitive task. Area of COP and mean velocity (Vm) were measured for as static postural stability.
Results: Area under the curve increased in the double leg stance position in the patients significantly (P<0.05). While mean velocity decreased by performing a dual task (P<0.05). The response to dual-tasking was not significant between the 2 groups(P>0.05).
Conclusion: Postural control deficits and increased of center of pressure’s sway were identified in participants with Knee osteoarthritis. Also performance of a cognitive task resulted in decrease of postural sway, but the dual- tasking did not change the postural performance of knee OA patients compared to healthy subjects.

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Abstract

Background and Aim: Proprioceptive problems, visuospatial deficits and muscle weakness are the main causes of weight bearing asymmetry and postural control impairment in chronic hemiparesis patients. The aim of this study was to investigate the correlation between center of pressure parameters in quiet standing with eyes open and closed and functional balance tests and symmetry index in these patients.

Materials and Methods: In this correlation study, 16 stroke patients (mean age: 52.937±10.109 years), were selected by simple non-probability sapling. Force plate, Functional Reach and Timed Up and Go tests and scales were used in order to investigate postural sway parameters in quiet standing, functional balance and symmetry index, respectively.

Results: Moderate to high significant correlation was obtained between Timed Up and Go test and symmetry index and most of the postural sway parameters in eyes closed condition, while Functional Reach test had only moderate significant correlation with standard deviation of velocity (anterior-posterior) and phase plane total. Also symmetry index showed moderate correlation with most of the postural sway parameters.

Conclusion: Current study demonstrates the role of vision and task in correlation between center of pressure parameters, balance tests and symmetry index.

Key words: Correlation, Symmetric weight bearing, Postural sway, Functional Reach, Timed Up and Go, Force plate, Quiet standing

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Background and Aim: The calculated parameters of the center of pressure (COP) are suitable indicators for evaluating balance in patients after rehabilitation. Therefore, determining the reliability level of each parameter is a matter of great importance. This study tried to determine the reliability of some parameters of the COP sway in patients with myofascial neck pain in different postural situations.

  

Materials and Methods: The present study is a test-retest reliability design. Twenty patients with myofascial neck pain performed a single and a double leg test with open and closed eyes on a force plate and with open eyes on foam in three sessions with a 30 minute intervals for 30 seconds. Antero-posterior and medio-lateral sway range, mean velocity and mean area of sway were calculated.

  

Results: The mean velocity showed high reliability (0.98) in all situations, but the other parameters were variable in different situations.

  

Conclusions: The results showed that some COP parameters are highly reliable in assessment of patients with myofascial neck pain.

  

Keywords: Reliability, Myofascial neck pain, Center of pressure, Force plate

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Background and Aim: Standing stability is resulted by normal functioning of various neuro-muscular and musculo-skeletal systems. Patients with below knee amputation cannot use ankle strategy due to limb loss and they have to rely on other mechanisms to improve their standing stability. The effect of prosthesis foot on standing stability of patients with below knee amputation is not well understood. Therefore, the aim of this study was to evaluate the stability of below knee amputees and determine the influence of prosthesis foot on stability

Materials and Methods:  Fourty subjects participated in this study. Participants were divided into three groups including:  (a) normal individuals, (b) amputees using SACH foot and (c) amputees using single axis foot. The stability of subjects was evaluated by use of a Kistler force plate. The subjects were asked to stand on the force plate for one minute and look forward with their hand at their sides. The stability was evaluated by use of some parameters such as excursion of Center of Pressure (COP) and path length and velocity of COP in mediolateral and anteroposterior directions. The difference between the stability of the subjects was determined using One-way ANOVA and Post Hoc test.

Results: There was a significant difference between stability of the three groups during standing with regard to path length and velocity of COP in mediolateral and anteroposterior directions (P < 0.05). No significant difference was reported with regard to all of the measured parameters when comparing normal individuals and amputees with single axis foot (P >0.05).

Conclusion: Below-knee amputees standing stability who are using single axis foot have the same standing stability compared to normal subjects; moreover, stability of amputees who are using SACH foot was surprisingly better than normal subjects in some of the parameters including path length and velocity of COP in mediolateral and anteroposterior directions.

Keywords: Standing stability, Below knee amputation, SACH foot, Single axis foot, Force plate