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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: Neck pain is one of the common diseases (66.7%), which contains different age's groups such as youn. Results of researches indicate prevalence of women neck pain is higher than men, so experiment in neck disease in female is more necessary. The aim of this study is to evaluate changes of postural stability in patient with muscular neck pain. 

Materials & Methods: Twenty patients and fifteen healthy subjects contribute in this study.  Postural sway in quiet standing was assessed in both limb stance (BLS), one limb stance (OLS) of dominant side, on a force platform with open eyes (rigid-open) and standing on a force platform with closed eyes (rigid-closed) and standing on the foam (10.5 cm-thick) with open eyes (foam-open) without shoes. All of above conditions were done with dual task. Mean changes of logarithmic displacement in medial-lateral and for- aft directions were calculated.

 Results: There are significant differences between two groups, especially following dual task, and difficult conditions of OLS and standing on the foam.

 Conclusion: Patients with neck pain have difficultly in postural control that need to attending in treatment and prevention of following damages.

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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: Cerebral palsy (CP) is the most common motor impairment in childhood and affects 2 in 1000 live births, in which postural and motor control involved. In hemiplegic type, two sides of the body have differences in postural tone that cause weight shift to the intact side. In these children postural disorders appear as postural stability disorder. The aim of this study is to assess the effect of lateral wedge insole on postural control in cerebral palsy children.
Materials and Methods:  Sixteen hemiplegic children attended in this program and stood in two conditions on the force plate with and without lateral wedge on the hard plate. Center of pressure displacement measured for medio-lateral and antro-posterio directions. Every test took 20 seconds. It was repeated 3 times.
Results: Range of sideways decreased significantly with use of 5º wedge. Also a shoe wedge of 5º provided symmetrical weight distribution.
Conclusion: The results represent that a 5º lateral wedge applied to the unaffected limb, can improve factors of postural control and gain the symmetry in hemiplegic children

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Background and Aim: Few studies have assessed the reliability of postural balance measures during dynamic balance performance that introduce additional challenging to postural control system. In addition sometimes in the static conditions some deficiencies of the postural control system may not be revealed obviously therefore the aim of this study was to assess the reliability of postural control parameters during functional performance on force plate in healthy subjects.
Materials and Methods:  Ten healthy male subjects (mean age: 25.4 years, weight: 68.2 kg height:176.9cm) participated  in this study. None of the subjects were involved in sport activities. Every subject performed three 15seconds trials of eyes open single leg stance on a force plate during dynamic balance task. Participants grasped object with hand at their waist level and release it at above shoulder level.  The reproducibility of the center of pressure (COP) deviations (average speed &length of path) was assessed. All participants were tested on 2 sessions with an inter-measurement interval of 7 days. COP data was collected for each trial. The intraclass correlation coefficient (ICC) was used as parameter of intra-session and inter-session (Test-Retest) reliability.
Results: The ICCs for intra-session reliability of average speed and length of COP path were  0.89 and 0.91  respectively. The ICCs for inter-session reliability were 0.95 and 0.96 respectively.
Conclusion: The study showed high and very high reliability for center of pressure measures during dynamic balance task. Therefore this dynamic performance can be used as a balance pattern in postural control assessment. These can be used as reliable parameters in dynamic postural control assessment due to high reliability of average speed and length of COP path

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Background and aim: The importance of cognitive resources was shown in dual task studies of postural control. However, there was no definite evidence on how verbal instructions influence the allocation of attention to postural control. Therefore, the objective of this study is to explore the effect of verbal instructions on postural performance.
Materials and Methods: this Cross-sectional study was performed in 20 young adults (23.95 ± 3.31). Parallel standing/ hard surface, parallel standing/ foam surface, tandem standing/ hard surface were used as postural tasks and the choice reaction time task were conducted as cognitive task. Dual- task performance was measured under three different instructions including to pay attention to cognitive task, to postural task, and equal attention to both tasks.
Results: Comparing the performance of postural tasks under three different instructions were conducted by One-way ANOVA and showed in parallel standing on hard surface (p=0.831), parallel standing on foam (p=0.433), tandem standing on hard surface (p=0.912) for path length of COP and instructions in parallel standing on hard surface (p=0.308), parallel standing on foam (p=0.414), tandem standing on hard surface (p=0.867) for mean velocity were not significant. Postural performance in single and dual task conditions was significant only in parallel standing/ foam surface (p=0.046).
Conclusion: various instructions could not influence the amount of attention allocated to automatic postural tasks.

 

 

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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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Background and Aim: Postural control is the ability of maintaining of the body posture in space. Peripheral and central factors have important role in muscle fatigue. Repetitive muscle contraction leads to muscle fatigue. If strength is educed up to 30% of maximum contraction can be disturbed stance control of subjects. The objective of the present study was to compare the effect of lumbar muscle fatigue on postural control in athlete and non-athlete subjects.

  

Materials and Methods: Fifteen men as athlete subjects and other fifteen matched men as non- athlete subjects participated in this study. Trunk extensor muscle fatigue was produced by dynamometer. Stance postural sways were evaluated by force platform device in bipedal stance with open eye.

  

Results: In pre-fatigue state there is no significant difference between two groups. Fatigue had significantly effect on postural sways in both group after Lumbar muscle fatigue specially in non-athlete group (P ≥ 0.05) .

  

Conclusion: The postural control of athletes after muscle fatigue was better than non athlete subjects probably due to better proprioception in athlete subjects.

  

Keywords: Muscle fatigue, Postural control, Force plattform.

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Backgrouna and Aim : Children with cerebral palsy have often movement and postural disorders. The purpose of this study is to evaluate the effect of new neoprene dynamic orthosis on balance in children with cerebral palsy.

  

Materials and Methods : This study is quazi experimental. Five children with cerebral palsy (spastic diplegia) with mean age of 9/6± 3.78 years old participated in this study. The degree of knee extension was measured using electrogoniometer. Center of Pressure(COP) displacement in anterior/posterior and medial/lateral planes and functional balance were also measured using kistler forceplate (BA, Kistler- Switzerland 9286) and berg test in two occasions, before and after wearing neoprene orthosis in a period of six weeks. Wilcoxon test was used for comparing data before and after 6 weeks.

  

Results : There was statistically significant difference in right knee extension before and after wearing orthosis (p<0/05). The result of this study show no statistically significant in COP parameters. However, functional balance of children with CP shows significant improvement using neoprene orthosis.

  

Conclusion : New neoprene orthosis can be effective in knee biomechanical alignment as well as functional balance

  

Keywords : Cerebral palsy, Lycra dynamic orthosis, Postural control

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Background and Aim: Patellofemoral pain syndrome (PFPS) is the most common overuse injury occurring at the knee. Reduction of proprioception, pain, changes in muscle activity patterns are seen in PFPS. Therefore these patients may demonstrate less balance. Thus the main objective of this study was to determine the postural control in patients with patellofemoral syndrome and compare it with healthy subjects.

Materials and Methods: Ten subjects (age 31.1 ± 5.31, weight 59.6 ± 8.95, height 1.62 ± 0.05) presenting with PFPS were compared with 10 matched control subjects (age 27.2 ± 1.81, weight 60.6 ± 2.36, height 1.67 ± 0.01).

Pain was measured with VAS scale and patella position was assessed using the method first described by McConnell. Force Plate was used to measures COP paths in sagittal and frontal plane with open and close eyes.

Results: The data showed that COP paths were different between PFPS and healthy subjects with open eyes in sagittal and frontal plane (P< 0.05). Means of COP paths increase in patients with PFPS. No differences were detected between PFPS and healthy subjects with closed eyes in sagittal and frontal plane.

Conclusion: Body sways increase in patients with PFPS with open eyes due to pain, lateral tracking patella and reduction of proprioception in knee.

Keyword:  Postural control, Patellofemoral syndrome, Open & close eye

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Background and Aim: This study was conducted dueto the limited results of past studies in relation to postural control in children with developmental coordination disorders and the importance of postural control with the ability to integrate the vestibular, visual and somatosensory inputs. In this study the postural control of the children with Developmental Coordination Disorder (DCD) and their normal peers was compared under the reduced or the conflicted sensory input conditions.

Materials and Methods: Twenty two children with Developmental Coordination Disorder (16 males, 6 females with mean age of 7 years old and 9 months, SD 1 year and 5 months) and 19 children with normal motor development (13 males, 6 females, with mean age of 6 years and 11 months, SD 1 year and 1 month) were evaluated. Standing balance, sensory organization and motor control strategy were evaluated using the sensory organization test (SOT).

Result: The results showed that the children with DCD had poorer function than the normal children in the composite equilibrium (p&le; 0.001), visual ratios (p=0.005) and vestibular ration (p=0.002). There were no meaningful differences between groups in their average somatosensory ratio. Additionally, children with Developmental Coordination Disorder had lower motor strategy scores than the normal children when they were forced to depend on vestibular cues alone (p < 0.05). The children with Developmental Coordination Disorder had deficits in standing balance control in conditions that included reduced or conflicting sensory signals. The visual and vestibular systems tended to be more involved in contributing to the balance deficits than the somatosensory system. Moreover, children with Developmental Coordination Disorder were tended to use hip strategy excessively when forced to rely primarily on vestibular signals to maintain postural stability.

Conclusion: In order to improve the postural control in the patients, the rehabilitation protocols should focus on the sensory-motor deficits.

Keywords: Postural control, Postural stability, Developmental Coordination Disorder