Center Of Pressure Displacement Research Articles

Variability of visually-induced center of pressure displacements is reduced while young adults perform unpredictable saccadic eye movements inside a moving room

This study investigated the modulation of center of pressure (CoP) displacements of young adults as they performed predictable and unpredictable saccadic eye movements in stationary and moving visual scenarios. We also examined whether the relationship between CoP displacements and visual stimulus, provided by the moving scenario, and gaze control itself, are affected by the demands of the saccadic tasks. Fifteen young adults (20.53 ± 2.1 years old) stood upright on a force plate, inside a moving room, wearing an eye tracker while performing three tasks: gaze fixation (fixating on a target in the center of the screen), predictable task (saccades while following a target which continuously appeared and disappeared on the right and left sides), and unpredictable task (similar to the previous task, but the participants did not know which side the target would appear on). For saccadic tasks, the target appeared at a frequency of 1.1 Hz and with eccentricity of 11.5 degrees of visual angle. Two blocks of six trials were performed: in the first block, the room remained stationary and in the second, it oscillated (0.6 cm amplitude; 0.2 Hz frequency). Mean amplitude of CoP displacements was lower in the saccadic tasks compared to the gaze fixation, in both conditions; and higher in the moving scenario than in the stationary condition. Variability of CoP displacements was lower in the unpredictable saccades than gaze fixation task. Saccade reaction time was longer in the unpredictable than predictable task. We conclude that CoP displacements are reduced to facilitate performance of the saccadic tasks regardless of conditions and task complexity. Furthermore, lower variability suggests modulation of CoP displacements to deal with the increased attentional demands associated with the performance of the unpredictable saccades, indicating the important role of visual task constraints in postural control.

Objective Evaluation of Risk of Falls in Individuals with Chronic Stroke: Feasibility Study

<h3>Research Objectives</h3> To evaluate the feasibility of the robotic fall-risk assessment performed on hunova to objectively quantify the risk of falls in individuals with chronic stroke. <h3>Design</h3> Cross-sectional study. <h3>Setting</h3> Balance Assessment and Training Lab. <h3>Participants</h3> Four individuals with hemiparesis post stroke, aged 62±2.7 years. <h3>Interventions</h3> Participants performed the fall-risk assessment on hunova- a commercial robotic platform for assessing balance. The assessment included multifaceted fall-driving components, including static and dynamic balance, sit-to-stand, limits of stability, responses to perturbations, walking speed and history of previous falls. A composite score for risk of falls, called as silver index (SI), between 0 (no risk) and 100 (high risk) was obtained using built-in machine learning based predictive model <h3>Main Outcome Measures</h3> silver index (risk of falls), Berg Balance Scale (BBS), Timed-Up and Go, Center of Pressure (CoP), walking speed <h3>Results</h3> The mean SI score for fall-risk for the stroke group was found to be 79.3±11.7 (min: 66, max: 91), suggesting moderate to high risk of falls. SI scores did not show any correlation with the functional outcomes of balance and mobility (BBS, TUG, walking speed). However, SI showed a linear trend with biomechanical outcomes (CoP displacement, CoP velocity, sway area, velocity during static and perturbed conditions) recorded during the SI assessments. <h3>Conclusions</h3> The current work shows the feasibility of using a robotic platform-based assessment to objectively quantify the risk of falls in individuals with chronic stroke. A large sample is needed to further prove the validity of the SI outcome before it is used for meaningful interpretations of the risk of falls. <h3>Author(s) Disclosures</h3> None.

A Greek traditional dance program for improving balance of young children

ABSTRACT The aim of this study was to evaluate the effects of a dance program on static and dynamic balance in young children (6.62 ± .65 years old). Forty-six children were randomly assigned to either an intervention group (24 children) who took part in a four-week dance program (three times a week, total 12 sessions, 45 min/session), or a control group (22 children). The dance program was a combination of Greek dances and Laban’s movement concept specifically designed for improving balance in young children. Prior to and after the intervention, the participants were assessed in static balance (one leg stance), dynamic balance and the jump-landing test. The results showed that the dance group performed significantly better in dynamic balance and peak-to-peak amplitude of Center of Pressure (CoP) in the mediolateral direction and total excursion of the CoP. There were no significant differences of the CoP displacement in anteroposterior direction and the jump-landing-test. It may be concluded that the dance program constitutes an effective activity for the development of young children’s static and dynamic balance. As balance is crucial for children’s motor development and the reduction of fall-related injuries, it is suggested corresponding dance activities should be part of primary physical education curriculum.

Influence of Augmented Visual Feedback on Balance Control in Unilateral Transfemoral Amputees.

Patients with a lower limb amputation rely more on visual feedback to maintain balance than able-bodied individuals. Altering this sensory modality in amputees thus results in a disrupted postural control. However, little is known about how lower limb amputees cope with augmented visual information during balance tasks. In this study, we investigated how unilateral transfemoral amputees incorporate visual feedback of their center of pressure (CoP) position during quiet standing. Ten transfemoral amputees and ten age-matched able-bodied participants were provided with real-time visual feedback of the position of their CoP while standing on a pressure platform. Their task was to keep their CoP within a small circle in the center of a computer screen placed at eye level, which could be achieved by minimizing their postural sway. The visual feedback was then delayed by 250 and 500 ms and was combined with a two- and five-fold amplification of the CoP displacements. Trials with eyes open without augmented visual feedback as well as with eyes closed were further performed. The overall performance was measured by computing the sway area. We further quantified the dynamics of the CoP adjustments using the entropic half-life (EnHL) to study possible physiological mechanisms behind postural control. Amputees showed an increased sway area compared to the control group. The EnHL values of the amputated leg were significantly higher than those of the intact leg and the dominant and non-dominant leg of controls. This indicates lower dynamics in the CoP adjustments of the amputated leg, which was compensated by increasing the dynamics of the CoP adjustments of the intact leg. Receiving real-time visual feedback of the CoP position did not significantly reduce the sway area neither in amputees nor in controls when comparing with the eyes open condition without visual feedback of the CoP position. Further, with increasing delay and amplification, both groups were able to compensate for small visual perturbations, yet their dynamics were significantly lower when additional information was not received in a physiologically relevant time frame. These findings may be used for future design of neurorehabilitation programs to restore sensory feedback in lower limb amputees.

Validity and reliability of standing balance control measurement on the left unilateral spatial neglect model

BACKGROUND: The present study developed a head-mounted display with the visual direction of a web camera modified to the right as a left unilateral spatial neglect (USN) model with respect to postural balance control. AIM: We aimed to estimate the validity and reliability of center of pressure (CoP) measurements in static standing balance (SSB) and dynamic standing balance (DSB) of healthy participants were using the USN model and to examine whether this model's use influenced postural balance control. METHOD: A portable CoP force plate was used to quantify postural balance control in 64 healthy participants as the model. The CoP displacement of the non-USN and USN models in the medial-lateral (ML) and anterior-posterior (AP) planes, CoP length, and bilateral load ratio in SSB and DSB to the right (R) and left (L) were evaluated. RESULTS: Regression analysis indicated that most CoP measurements have excellent concurrent validity. Bland–Altman plots showed good agreement between the non-USN and USN models in the CoP measurements. Test-retest reliability estimation between two times measurements varied in the frontal and sagittal planes. A Comparison of the results demonstrated that the CoP-AP and CoP length changed (-1.40% and 7.67%, respectively) significantly in SSB (P&lt;0.05). Moreover, the CoP-AP changed very significantly in DSB-R and DSB-L (-1.50% and 1.86%, respectively) in opposite directions (P&lt;0.01) when the subjects performed as the model. CONCLUSION: CoP measurements are valid and reliable to quantify standing balance control in both non-USN and USN models that appear to modulate changes in postural adaptation and adjustment.

유소년 축구선수의 킥 동작에 따른 운동역학적 분석

We projected of analysis that was aimed at enhanced kick performance of football posture for adolescent athletes and was measured lower limb angle, displacement of plantar center of pressure(COP) were occurred during each inside kick and instep kick(long kick).<BR> Healthy adolescent athletes(n=10, male, age: 13.6±.52) were recruited for our project. Range of motion(ROM) over Hip, Knee and Ankle Joint were measured by three-dimensional analysis using inertial measurement units. COP of each kicking and support foot was measured from sensor insole. Statistical analysis of independent t-test was performed(p<.05).<BR> The results revealed that inside kick caused greater ROM than instep kick over the phase for preparing kick in almost all joints. Inside kick showed smaller ROM than instep kick over the phase for kicking. COP displacement of support foot from inside kick was smaller than instep kick with significant(p<.05) when the event of initial contact of support foot or toe-off of kicking foot from the ground arose.<BR> These results suggest inside kick and instep kick have the different tendency of ROM over joint angle of lower limbs each other and have the different tendency of behavior strategy for stability of center of body in football athletes when the foot for support of kicking contacted on the ground.

Variability in the Center of Mass State During Initiation of Accurate Forward Step Aimed at Targets of Different Sizes

Motor control for forward step initiation begins with anticipatory postural adjustments (APAs). During APAs, the central nervous system controls the center of pressure (CoP) to generate an appropriate center of mass (CoM) position and velocity for various task requirements. In this study, we investigated the effect of required stepping accuracy on the CoM and CoP parameters during APA for a step initiation task. Sixteen healthy young participants stepped forward onto the targets on the ground as soon as and as fast as possible in response to visual stimuli. Two target sizes (small: 2 cm square and large: 10 cm square) and two target distances (short: 20% and long: 40% of the body height) were tested. CoP displacement during the APA and the CoM position, velocity, and extrapolated CoM at the timing of the takeoff of the lead leg were compared among the conditions. In the small condition, comparing with the large condition, the CoM position was set closer to the stance limb side during the APA, which was confirmed by the location of the extrapolated center of mass at the instance of the takeoff of the lead leg [small: 0.09 ± 0.01 m, large: 0.06 ± 0.01 m, mean and standard deviation, F(1, 15) = 96.46, p < 0.001, η2 = 0.87]. The variability in the mediolateral extrapolated center of mass location was smaller in the small target condition than large target condition when the target distance was long [small: 0.010 ± 0.002 m, large: 0.013 ± 0.004 m, t(15) = 3.8, p = 0.002, d = 0.96]. These findings showed that in the step initiation task, the CoM state and its variability were task-relevantly determined during the APA in accordance with the required stepping accuracy.

Effects of global postural reeducation on postural control, dynamic balance, and ankle range of motion in patients with hallux abducto valgus. A randomized controlled trial.

Hallux abducto valgus (HAV) is a common musculoskeletal disorder that has been addressed surgically. Nevertheless, the manual therapy approach may play an important role in the management of this condition. The present study aimed to determine the effectiveness of global postural reeducation (GPR) in subjects with symptomatic mild to moderate HAV in static postural control, dynamic stability, and ankle dorsiflexion range of motion (DFROM). A total of 80 patients with mild to moderate symptomatic HAV were allocated to the intervention group (GPR) or control group (CG) (no treatment) for 8 weeks. Outcome measures were assessed at baseline at 4 and 8 weeks including static postural control (Romberg test), dynamic balance (Star Excursion Balance Test [SEBT]), and ankle DFROM (Weight-Bearing Lunge Test [WBLT]). No improvements were observed at 4 weeks, but there were improvements at 8 weeks in: static postural control mediolateral displacement (X) of center of pressure (CoP) in both eyes open (EO) and eyes closed (EC): XEO (t(36) = 2.892, p = .006, d = 0.67); XEC (t(68) = 2.280, p = .026, d = 054); and velocity (V) of CoP displacement: VEO (t(68) = 2.380, p = .020, d = 0.57); VEC (t(36) = 2.057, p = .047, d = 0.37). It were also improvements in: WBLT (t(36) = -2.869, p = .007, d = 0.54) and SEBT at three directions (anterior, ANT; posteromedial, PM; and posterolateral, PL): SEBT.ANT (t(36) = -2.292, p = .028, d = 0.23); SEBT.PM (t(36) = -4.075, p < .001, d = 0.43); SEBT.PL (t(62) = -3.506, p = .001, d = 0.34). The present study showed that GPR compared to the CG might be effective in enhancing ankle function including postural control, dynamic balance, and DFROM.

The association of reactive balance control and spinal curvature under lumbar muscle fatigue.

BackgroundAlthough low back fatigue is an important intervening factor for physical functioning among sedentary people, little is known about its possible significance in relation to the spinal posture and compensatory postural responses to unpredictable stimuli. This study investigates the effect of lumbar muscle fatigue on spinal curvature and reactive balance control in response to externally induced perturbations.MethodsA group of 38 young sedentary individuals underwent a perturbation-based balance test by applying a 2 kg load release. Sagittal spinal curvature and pelvic tilt was measured in both a normal and Matthiass standing posture both with and without a hand-held 2 kg load, and before and after the Sørensen fatigue test.ResultsBoth the peak anterior and peak posterior center of pressure (CoP) displacements and the corresponding time to peak anterior and peak posterior CoP displacements significantly increased after the Sørensen fatigue test (all at p < 0.001). A lumbar muscle fatigue led to a decrease of the lumbar lordosis in the Matthiass posture while holding a 2 kg load in front of the body when compared to pre-fatigue conditions both without a load (p = 0.011, d = 0.35) and with a 2 kg load (p = 0.000, d = 0.51). Also the sacral inclination in the Matthiass posture with a 2 kg additional load significantly decreased under fatigue when compared to all postures in pre-fatigue conditions (p = 0.01, d = 0.48). Contrary to pre-fatigue conditions, variables of the perturbation-based balance test were closely associated with those of lumbar curvature while standing in the Matthiass posture with a 2 kg additional load after the Sørensen fatigue test (r values in range from −0.520 to −0.631, all at p < 0.05).ConclusionThese findings indicate that lumbar muscle fatigue causes changes in the lumbar spinal curvature and this is functionally relevant in explaining the impaired ability to maintain balance after externally induced perturbations. This emphasizes the importance for assessing both spinal posture and reactive balance control under fatigue in order to reveal their interrelations in young sedentary adults and predict any significant deterioration in later years.

Immediate and Short-term Effect of Quadriceps Kinesio-Taping on Postural Sway in Children with Spastic Cerebral Palsy: A Before-After Trial

Background: Kinesio-Tape (KT) is a common method used in rehabilitation, but the KT short-term therapeutic effects on children with cerebral palsy (CP) are unclear yet. Objectives: This study aims to investigate the short-term and immediate effects of KT on postural sway in children with CP. Methods: In this before- and after-study, 27 children aged between 4 and 11 years old with spastic CP were included. Immediate and short-term effects of KT on Quadriceps muscle (QcM) were then assessed using time-up and go test (TUG) and COP (center of pressure) displacement in five assessments. Results: The results of Repeated Measure Analysis show that the short-term use of KT on QcM could reduce COP displacement in both the mediolateral and anteroposterior directions and improve the balance among children with CP (P &lt; 0.05). Conclusions: The immediate effects of KT on the QcM did not change the COP’s displacement and balance. It was demonstrated that the short-term use of KT in QcM could improve the balance of COP and reduce its displacement.

Test-Retest Reliability of Low-Cost Posturography for Assessing Postural Stability Control Performance during Standing.

Postural stability control performance assessment is necessary in providing important information for individuals who are at risk of falling or who have balance impairment. Instrumented assessment is suggested as a valid and reliable test, but the cost and the difficulty of setup are significant limitations. The aim of this cross-sectional (test-retest reliability) study was to develop and determine the reliability of a low-cost posturography for assessing postural stability control performance during standing. The low-cost posturography was developed with four load cells and an acrylic platform. The center of pressure (COP) displacement and velocity were analyzed using written software. Test-retest reliability was performed with six different standing postural stability tests in twenty healthy volunteers on two different days. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), coefficient of variation (CV), and Bland–Altman plot and limits of agreements (LOA) were used for analyses. The low-cost posturography was accurate (ICC = 0.99, p < 0.001; SEM = 0.003 cm) when compared to the true with calculated X and Y coordinates, with a moderate to excellent test-retest reliability for both COP displacement (ICCs ranged 0.62–0.91, p < 0.05; SEMs ranged 17.92–25.77%) and COP velocity (ICCs ranged 0.62–0.91, p < 0.05; SEMs ranged 18.09–27.69%) in all standing postural stability tests. Bland–Altman plots and LOAs suggested good agreement of tested parameters from the developed low-cost posturography between different days. In conclusion, the developed low-cost posturography had adequate reliability for assessing COP displacement and velocity during standing postural control stability performance tests.

Effects Of Bafa Wubu Of Tai Chi Practice On The Balance Control Among Older Adults

PURPOSE: To examine the effectiveness of Bafa Wubu of Tai Chi (BWTC) practice in improving the center of pressure (COP) variables, proprioception, and plantar tactile sensitivity. METHODS: A total of 31 participants were randomly assigned to control (CON, N = 16, received no intervention) and BWTC (BWTC, N = 15, received 16-week Tai Chi practice) groups. Data of COP variables, proprioception, and plantar tactile sensitivity were collected at week 0 and week 17. The outcome variables were root mean square (RMS) and mean velocity of COP displacements during the double stance with eyes open (DO)/ eyes closed (DC); single stance with eyes open (SO) / eyes closed (SC). The proprioception of dominant leg knee extension/flexion, ankle plantar/dorsal flexion was collected. The plantar tactile sensitivities of the heel, arch, metatarsal 1&5, and great toe were collected. A Two-way ANOVA with repeated measures was used to examine the results. RESULTS: After the intervention, significant group by time interactions were observed. Significantly decreased COP variables observed for the BWTC group in RMS of COP in medial-lateral (ML) directions during DO (BWTC group: week 0: 6.1 ± 0.4, week 17: 4.8 ± 0.4, CON group: week 0: 5.3 ± 0.4, week 17: 5.8 ± 0.4, P < 0.001) and SC (BWTC group: week 0: 30.6 ± 4.4, week 17: 17.9 ± 3.1, CON group: week 0: 29.3 ± 0.4, week 17: 27.3 ± 0.4, P = 0.023) conditions, the mean velocity of COP in anterior-posterior (BWTC group: week 0: 367.5 ± 65.0, week 17: 200.7 ± 37.5, CON group: week 0: 261.7 ± 65.0, week 17: 268.0 ± 37.5, P = 0.017) and ML (BWTC group:week 0: 271.2 ± 40.1, week 17:146.0 ± 17.1, CON group: week 0: 222.0 ± 40.1, week 17: 196.9 ± 17.1, P = 0.046) directions during SC condition, proprioception threshold decreased knee extension (BWTC group: week 0: 3.8 ± 0.6, week 17: 2.7 ± 0.5, CON group: week 0: 3.3 ± 0.6, week 17: 3.6 ± 0.5, P = 0.012), plantar tactile sensitivity threshold decreased at the arch (BWTC group: week 0: 4.2 ± 0.2, week 17: 3.8 ± 0.2, CON group: week 0: 4.5 ± 0.2, week 17: 4.6 ± 0.2, P = 0.024). CONCLUSION: The outcomes indicated that after 16-week BWTC practice, practitioners showed improved COP variables, knee proprioception threshold, and arch tactile sensitivity. BWTC can be an effective rehabilitation modality to improve fall-risk related balance and sensory factors among older adults.

Effects of load carrying techniques on gait parameters, dynamic balance, and physiological parameters during a manual material handling task

PurposeSince construction workers often need to carry various types of loads in their daily routine, they are at risk of sustaining musculoskeletal injuries. Additionally, carrying a load during walking may disturb their walking balance and lead to fall injuries among construction workers. Different load carrying techniques may also cause different extents of physical exertion. Therefore, the purpose of this paper is to examine the effects of different load-carrying techniques on gait parameters, dynamic balance, and physiological parameters in asymptomatic individuals on both stable and unstable surfaces.Design/methodology/approachFifteen asymptomatic male participants (mean age: 31.5 ± 2.6 years) walked along an 8-m walkway on flat and foam surfaces with and without a load thrice using three different techniques (e.g. load carriage on the head, on the dominant shoulder, and in both hands). Temporal gait parameters (e.g. gait speed, cadence, and double support time), gait symmetry (e.g. step time, stance time, and swing time symmetry), and dynamic balance parameters [e.g. anteroposterior and mediolateral center of pressure (CoP) displacement, and CoP velocity] were evaluated. Additionally, the heart rate (HR) and electrodermal activity (EDA) was assessed to estimate physiological parameters.FindingsThe gait speed was significantly higher when the load was carried in both hands compared to other techniques (Hand load, 1.02 ms vs Head load, 0.82 ms vs Shoulder load, 0.78 ms). Stride frequency was significantly decreased during load carrying on the head than the load in both hands (46.5 vs 51.7 strides/m). Step, stance, and swing time symmetry were significantly poorer during load carrying on the shoulder than the load in both hands (Step time symmetry ration, 1.10 vs 1.04; Stance time symmetry ratio, 1.11 vs 1.05; Swing time symmetry ratio, 1.11 vs 1.04). The anteroposterior (Shoulder load, 17.47 mm vs Head load, 21.10 mm vs Hand load, −5.10 mm) and mediolateral CoP displacements (Shoulder load, −0.57 mm vs Head load, −1.53 mm vs Hand load, −3.37 ms) significantly increased during load carrying on the shoulder or head compared to a load in both hands. The HR (Head load, 85.2 beats/m vs Shoulder load, 77.5 beats/m vs No load, 69.5 beats/m) and EDA (Hand load, 14.0 µS vs Head load, 14.3 µS vs Shoulder load, 14.1 µS vs No load, 9.0 µS) were significantly larger during load carrying than no load.Research limitations/implicationsThe findings suggest that carrying loads in both hands yields better gait symmetry and dynamic balance than carrying loads on the dominant shoulder or head. Construction managers/instructors should recommend construction workers to carry loads in both hands to improve their gait symmetry and dynamic balance and to lower their risk of falls.Practical implicationsThe potential changes in gait and balance parameters during various load carrying methods will aid the assessment of fall risk in construction workers during loaded walking. Wearable insole sensors that monitor gait and balance in real-time would enable safety managers to identify workers who are at risk of falling during load carriage due to various reasons (e.g. physical exertion, improper carrying techniques, fatigue). Such technology can also empower them to take the necessary steps to prevent falls.Originality/valueThis is the first study to use wearable insole sensors and a photoplethysmography device to assess the impacts of various load carrying approaches on gait parameters, dynamic balance, and physiological measures (i.e. HR and EDA) while walking on stable and unstable terrains.

Graph-theoretical analysis of EEG functional connectivity during balance perturbation in traumatic brain injury: A pilot study.

Traumatic brain injury (TBI) often results in balance impairment, increasing the risk of falls, and the chances of further injuries. However, the underlying neural mechanisms of postural control after TBI are not well understood. To this end, we conducted a pilot study to explore the neural mechanisms of unpredictable balance perturbations in 17 chronic TBI participants and 15 matched healthy controls (HC) using the EEG, MRI, and diffusion tensor imaging (DTI) data. As quantitative measures of the functional integration and segregation of the brain networks during the postural task, we computed the global graph‐theoretic network measures (global efficiency and modularity) of brain functional connectivity derived from source‐space EEG in different frequency bands. We observed that the TBI group showed a lower balance performance as measured by the center of pressure displacement during the task, and the Berg Balance Scale (BBS). They also showed reduced brain activation and connectivity during the balance task. Furthermore, the decrease in brain network segregation in alpha‐band from baseline to task was smaller in TBI than HC. The DTI findings revealed widespread structural damage. In terms of the neural correlates, we observed a distinct role played by different frequency bands: theta‐band modularity during the task was negatively correlated with the BBS in the TBI group; lower beta‐band network connectivity was associated with the reduction in white matter structural integrity. Our future studies will focus on how postural training will modulate the functional brain networks in TBI.

Systematically Increased External Loads Secured Inferior to Younger and Older Adults’ Center of Mass Improves Postural Control without Compromising Functional Motor Performance

Few studies have investigated the effect of external loads secured inferior to the center of mass (COM) on postural control and motor performance in younger and older adults. In the present study, we investigated the effect of systematically increased external loads secured inferior to the COM on young (N = 15, age [years]: M = 26.67, SD= 3.45) and older adults’ (N = 15, age [years]: M = 67.4, SD= 7.69) center of pressure displacement and velocity, and also dart throwing performance in four different load conditions: 1) no load (control condition), 2) loading with 5% of body mass, 3) loading with 10% of body mass, and 4) loading with 20% of body mass. Overall, older adults had higher COP displacement and velocity in both anterior/posterior (AP) and Medio-lateral (ML) directions and poorer dart throwing scores than younger adults. Despite no significant difference in dart throwing performance for the different load conditions within each age group, loading with 10% and 20% of body mass reduced AP COP displacement relative to control for both study groups, with 20% body mass also reducing AP COP velocity relative to control for both study groups. In conclusion the present findings reveal that external loads secured inferior to older and younger adults’ COM may enhance postural control without compromising motor performance. The findings were discussed in the context of fall-prevention and athletic performance.

The Immediate Effect of Kinesio Taping on the Balance Performance of Patients with Chronic Ankle Sprains: A Randomized Controlled Trial

Background: Lateral ankle sprain is a common injury resulting from a rapid supination moment that damages the lateral ligaments and cartilaginous surfaces and contributes to the deterioration of functional ankle stability and balance among individuals. Objectives: This study aimed to investigate the immediate effect of Kinesio Taping (KT) on the balance performance of patients with chronic ankle sprains. Methods: This randomized, single-blind, parallel-group study was performed using the allocation concealment method. Sixty individuals (27 males and 33 females) with a history of ankle sprain were recruited and randomly assigned to one of the experimental (KT; n = 30) or control (non-KT; n = 30) groups. The intervention continued for two consecutive days, including four assessment sessions before and after taping on the first day and before and after removing KT on the second day. The mean and standard deviation (SD) of the center of pressure (COP) displacement and the velocity and SD of COP displacement were measured in the ant-post and med-lat directions following inversion and anterior perturbations. For data analysis, analysis of variance (ANOVA) test was performed using SPSS software version 22. This study was registered in the Iranian Registry of Clinical Trials (IRCT2013110415262N1). Results: The results of repeated measures ANOVA revealed an increase in the mean changes of COP displacement, velocity of COP displacement, and SD of COP displacement in the med-lat direction during inversion perturbation immediately after KT (P = 0.031, P = 0.005, and P = 0.011, respectively) and 24 hours after KT (P = 0.019, P = 0.002, and P = 0.009, respectively), compared to the control group. Moreover, during anterior perturbation, a significant increase was observed in the SD of COP displacement immediately and 24 hours after applying KT in the med-lat direction, compared to the control group (P = 0.022 and P = 0.016, respectively). Conclusions: Our findings revealed that KT might not improve the COP sway during perturbation in individuals with ankle sprains.

Frontal plane roll-over analysis of prosthetic feet

In prosthetic walking mediolateral balance is compromised due to the lack of active ankle control, by moments of force, in the prosthetic limb. Active control is reduced to the hip strategy, and passive mechanical stability depends on the curvature of the prosthetic foot under load. Mediolateral roll-over curvatures of prosthetic feet are largely unknown. In this study we determined the mediolateral roll-over characteristics of various prosthetic feet and foot-shoe combinations. Characteristics were determined by means of an inverted pendulum-like apparatus. The relationship between the centre of pressure (CoP) and the shank angle was measured and converted to roll-over shape and effective radius of curvature. Further, hysteresis (i.e., lagging in CoP displacement due to material compliance or slip) at vertical shank angle was determined from the hysteresis curve. Passive mechanical stability varied widely, though all measured foot-shoe combinations were relatively compliant. Mediolateral motion of the CoP ranged between 4 mm and 40 mm, thereby remaining well within each foot’s physical width. Derived roll-over radii of curvature are also small, with an average of 102 mm. Hysteresis ranges between 20% and 115% of total CoP displacement and becomes more pronounced when adding a shoe. This may be due to slipping of the foot core in its cosmetic cover, or the foot in the shoe. Slip may be disadvantageous for balance control by limiting mediolateral travel of the CoP. It may therefore be clinically relevant to eliminate mediolateral slip in prosthetic foot design.

Motor dual task with eyes closed improves postural control in patients with functional motor disorders: A posturographic study.

Functional motor disorders (FMD) are highly disabling neurological conditions in which postural control deficits increase the risk of falls and disability in performing daily living activities. Scattered evidence suggests that such disturbances may depend on abnormal attentional focus and might improve with distraction. How do motor and cognitive dual tasks performed under two different sensory conditions shape postural control in patients with FMD. This posturographic study involved 30 patients with FMD (age, 45.20 ± 14.57 years) and 30 healthy controls (age, 41.20 ± 16.50 years). Postural parameters were measured with eyes open, and eyes closed in quiet stance (single task) and on a motor dual task (m-DT) and a calculation (cognitive) dual task (c-DT). The dual task effect (DTE, expressed in percentage) on motor and cognitive performance was calculated for sway area, length of Center of Pressure (CoP), and velocity of CoP displacement. There was a statistically significant three-way interaction between task, condition, and group for the DTE on sway area (p = 0.03). The mean sway area DTE on the motor task in the eyes-closed condition was increased by 70.4 % in the healthy controls, while it was decreased by 1% in the patient group (p = 0.003). No significant three-way interaction was observed for the DTE on length of CoP and velocity of CoP displacement. This study provides novel preliminary evidence for the benefit of a simple motor dual task in the eyes closed condition as a way to improve postural control in patients with FMD. These findings are relevant for the management of postural control disorders in patients with FMD.

Effect of PSSE on postural sway in AIS using center of pressure.

We haven't known whether the center of pressure (COP) could be considered as a better indicator in the evaluation of posture and balance change after the physiotherapeutic scoliosis specific exercise (PSSE) during level walking. The objective of this study was: 1) to determine changes in COP displacement in anterior-posterior (COP-AP) and medial-lateral (COP-ML) for AIS following the PSSE; 2) to find out COP oscillation(COP-OS) from the midline for the left and right foot; 3) to investigate max pressure at the forefoot, midfoot and hindfoot bilaterally. AIS patients with three reflective markers on their back walked on the pressure sensors embedded treadmill at 2 km/h and their trunks were also registered by DIERS Formetric 4D system. Each child received the PSSE for 12 weeks by the same physical therapist and had a dynamic pressure analysis before and after the PSSE. Six AIS children at a mean age of 13 years and with averaged major Cobb angle of 26°were enrolled. There was an increase in COP-AP (15%) and a decrease in the COP-ML (-25%) following the PSSE. COP-OS on the left foot shifted farther away from the midline (about 16%) as the right side moved closer (-1%), which becomes more symmetrical (Pre-PSSE: 0.86mm & Post-PSSE: 0.32mm). There were increased pressures on the left (35%) and right (26%) hallux after PSSE. Pressure metrics, especially including COP-ML, COP-AP, COP-OS, and peak pressures on the forefoot, may be opted as optimal predictors to posture improvements by the means of PSSE.

Postural control during quiet standing and voluntary stepping response tasks in individuals post-stroke: a case-control study

ABSTRACT Background: Postural control impairments following a stroke have an impact on mobility, reduce independence, and increase the risk of falls. Assessing these impairments during tasks representative of real-life situations, such as quiet standing (QS) and voluntary stepping response (VSR), will enhance our understanding of how the postural control system is impaired in individuals post-stroke (IPS). It will also inform the development of a more targeted and effective rehabilitation to prevent falls in IPS. Objectives: Identify the postural control impairments encountered by IPS during QS and VSR. Methods: Twenty IPS and 16 healthy controls were recruited to perform QS and VSR tasks, while ground reaction forces and whole-body motion were measured. Displacement and speed variation of the COM, center of pressure (COP) displacement and spatiotemporal data were calculated and compared between groups. Results: During QS, IPS exhibited greater maximal COP displacement in mediolateral direction, COM displacement in vertical direction and COM speed excursions compared to controls. During VSR, IPS exhibited smaller step length, braking force, posterior foot placement in relation to the pelvis and COM anteroposterior excursion compared to controls. IPS presented less static and dynamic postural stability compared to controls. Conclusions: Greater postural sway during QS, smaller anteroposterior COM displacement before losing balance and altered voluntary recovering steps during VSR could place IPS at more risk of falling when they face a postural challenge in the community. These novel results will improve the current knowledge base and should be considered in IPS rehabilitation.