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

IntroductionPostural control is essential for humans to maintain balance under both static and dynamic conditions. A variety of unstable support surfaces are used to evaluate postural control. Balance foam pads are relatively expensive, whereas natural rubber pads use a natural material with equivalent viscoelastic properties that are inexpensive and widely available. No postural sway and reliable data existed to support the practice of using a natural rubber pad. The purposes of the study were to determine the test-retest reliability of postural sway by using a natural rubber pad and to compare postural sway in healthy adults while using a foam pad, a natural rubber pad and a firm surface.MethodsNineteen healthy participants were measured for centre of pressure (COP) velocity and displacement during a quiet stance, with their eyes closed, on a balance foam pad (blue foam – Airex®), a natural rubber pad and a firm surface on a force platform. Two repeated sessions were conducted three days apart. Intraclass correlation coefficients were used to determine the test-retest reliability. A one-way repeated measures ANOVA was used to compare the three surface conditions.ResultsThe natural rubber pad demonstrated moderate to good reliability for COP velocity and COP displacement. Also, there were no significant differences in anteroposterior (AP) and mediolateral (ML) COP velocity and displacement between the balance foam pad and the natural rubber pad.ConclusionsOur findings indicate that a natural rubber pad could be employed as a low-cost alternative to the balance foam pad for evaluating the balance of healthy adults.

Changes in center of pressure velocities during obstacle crossing one year after bariatric surgery

The effects of postural training on postural stability and vestibulospinal reflexes (VSRs) were investigated in normal subjects. A period (23 minutes) of repeated episodes (n = 10, 50 seconds) of unipedal stance elicited a progressive reduction of the area covered by centre of pressure (CoP) displacement, of average CoP displacement along the X and Y axes and of CoP velocity observed in this challenging postural task. All these changes were correlated to each other with the only exception of those in X and Y CoP displacement. Moreover, they were larger in the subjects showing higher initial instability in unipedal stance, suggesting that they were triggered by the modulation of sensory afferents signalling body sway. No changes in bipedal stance occurred soon and 1 hour after this period of postural training, while a reduction of CoP displacement was apparent after 24 hours, possibly due to a beneficial effect of overnight sleep on postural learning. The same period of postural training also reduced the CoP displacement elicited by electrical vestibular stimulation (EVS) along the X axis up to 24 hours following the training end. No significant changes in postural parameters of bipedal stance and VSRs could be observed in control experiments where subjects were tested at identical time points without performing the postural training. Therefore, postural training led to a stricter control of CoP displacement, possibly acting through the cerebellum by enhancing feedforward mechanisms of postural stability and by depressing the VSR, the most important reflex mechanism involved in balance maintenance under challenging conditions.

Carrying asymmetric loads while walking on an uneven surface

Effects of heel height and high-heel experience on foot stability during quiet standing

Laboratory-based measurement of standing balance in individuals with knee osteoarthritis: A systematic review

Balance is key to controlling body posture. Balance is typically assessed by measures of the body's vertical orientation, obtained by balancing out the forces acting on different body segments. The ability to maintain balance is assessed by evaluating centre of pressure (CoP) displacement; such assessments are typically used to evaluate responses to a treatment process. This study evaluated the efficiency of compensatory reactions in children according to the extent of thoracic kyphosis and lumbar lordosis. The study enrolled 312 children aged 8‒12 years, including 211 patients with postural disorders: thoracic kyphosis outside the 47‒50-degree range and lordosis outside the 38‒42-degree range (study group). A control group was also recruited and comprised 101 children without postural disorders. The DIERS formetric 4D system was used to assess posture and CoP displacement. Children in the study group showed a significantly greater range of CoP displacement than children in the control group. The kyphosis angle correlated with the maximum CoP displacement in the coronal plane and the maximum CoP displacement in the sagittal plane during gait. The kyphosis angle also correlated with the maximum CoP displacement back in the static test. The size of the lordosis angle correlated with the maximum displacement of CoP in the coronary plane during gait, and with the maximum displacement of CoP toward the left, forward, and backward in the static test. The correlation coefficient of the lordosis angle with displacement of the CoP in the sagittal plane was 0.999. We found an association between kyphosis and lordosis and the amplitude of CoP displacement, which may reflect the postural control system's response to biomechanical destabilisation caused by changes in kyphosis and lordosis.The lordosis angle correlation strength for displacement of CoP in sagittal plane is 0.999 and adopts a linear value.

Advancing age is associated with more impaired mediolateral balance control after step down task

Altered postural control has been observed in chronic ankle instability (CAI). Kinesiophobia (fear of re-injury) has been identified as a factor influencing postural stability. Therefore, postural control was assessed during jump landing among CAI athletes with and without kinesiophobia, as well as healthy controls. A total of 60 participants were recruited, including 40 individuals with CAI and 20 healthy controls. The CAI group was subdivided into two cohorts: 20 subjects with kinesiophobia (Tampa Scale of Kinesiophobia score > 37) and 20 without kinesiophobia. All participants performed a single-leg jump landing task on a force plate. The following postural stability metrics were calculated: time to stabilization (TTS), and the mean and standard deviation of center of pressure (COP) displacement and velocity in the anterior-posterior (AP), medial-lateral (ML), and total directions. CAI subjects with kinesiophobia exhibited longer TTSs in the AP (p = 0.019), vertical, and total directions (p < 0.001, p = 0.015, p = 0.002) than healthy subjects. Additionally, CAI subjects with kinesiophobia demonstrated a significant increase in the velocity of COP displacement in the AP and ML directions (p < 0.001, p = 0.004). These individuals showed greater variability in the velocity of COP displacement in the AP direction and in COP displacement in the ML direction than healthy subjects (p < 0.001). Also, CAI with kinesiophobia group presented less variability in the velocity of COP displacement in the ML direction than other groups (p < 0.001, p = 0.026). CAI with kinesiophobia group needed more time and more velocity in the AP direction than without kinesiophobia group (p = 0.003). Individuals with a high fear of re-injury may perceive the jump landing task as threatening, requiring more time to land and regain stability. This fear can restrict the variability of velocity in the ML direction, resulting in decreased control over the AP direction due to limitations on managing degrees of freedom.

Assistive devices, such as Exoskeletons (EXOs) can enhance endurance, but could inadvertently alter body mechanics, compromise balance, and elevate fall risk, particularly under fatigue. We evaluated effects of an EXO on postural stability during standing still and sustained trunk flexion tasks as users become fatigued during intermittently performed tasks. As trunk bending is common across many occupational/routine tasks, a repetitive 45° trunk flexion task was selected. In this controlled laboratory study, symmetric and asymmetric trunk flexion tasks were performed by twelve participants with a Back-support EXO until medium-high fatigue level (7/10 on Borg CR10 scale). Outcomes showed that the device increased trunk flexion durations (~16~25%), and upper-body movement beyond intended position. EXO-use improved stability by reducing maximum deviation (~22%) and mean velocity (~57%) of Center of Pressure (COP) co-ordinates. Asymmetric trunk flexion without assistance led to highest mean velocity of COP during fatigued state, but the same remained lower (~67%) with EXO-use, even with fatigue. The device decreased variance of COP during in medial/lateral direction (~44%), but increased the same in anterior/posterior direction by the same amount. Efforts in this study contribute towards understanding implications of using assistive devices for improving human performance across diverse applications.

A stable quiet stance is achieved by controlling the relative position of the center of pressure and the vertical projection of the center of mass. The best postural performances include efficient strategies to mitigate external perturbations. Footwear impacts postural stability and strategy by affecting cutaneous proprioception and ankle proprioception in the case of heeled shoes. The purpose of this study was to quantify the effects of four common footwear conditions, i.e. barefoot, sports, flats, and heels, on postural stability and strategy during quiet standing of healthy young women. Postural stability and strategy were assessed overall and in the antero-posterior and medio-lateral directions using five parameters: total sway, average center of pressure (COP) velocity, α value computed using detrended fluctuation analysis, hip over ankle ranges of motion, and power of the COP time series. Significant differences with barefoot were consistently found when wearing heels, namely a decrease in postural sway and average COP velocity. Results seemed counter-intuitive as they indicate an apparent increase in postural stability when wearing heels. A deeper analysis revealed a more complex scheme. A potential tightening of the motion when wearing heels, combined with an increase of the neutral plantarflexion angle, shifts the postural strategy towards a predominant hip strategy. Finally, proprioception did not play a key role. This study highlighted the complexity of the multifactorial interactions between footwear characteristics and postural strategies. Additional work is needed to develop footwear that will enhance postural stability of populations at risk, such as pregnant women or the elderly.

BackgroundPosturography is a diagnostic technique that quantifies postural control through Centre of Pressure (CoP) displacement analysis on a force platform. Footwear characteristics, particularly heel-to-toe drop, may influence balance by modifying plantar pressure distribution and proprioceptive feedback. The aim of this study was to evaluate the impact of different footwear drops (0 mm, 5 mm, 10 mm) on postural control in healthy young adults, considering sex, BMI, and shoe size.MethodsA cross-sectional study was conducted in 117 participants (56 men, 61 women) using the Dinascan/IBV® platform and the Romberg test. CoP displacement and velocity were analyzed.ResultsSignificant differences were observed in CoP total displacement (p < 0.001), mean velocity (p < 0.001), and medio-lateral dispersion (p = 0.024) when comparing 0 mm to 5 mm and 10 mm drops. Sex differences were significant at 0 mm drop for maximum medio-lateral force (p < 0.001) and mean velocity (p = 0.042), with men exhibiting greater values. At 5 mm drop, men showed significantly higher swept area (p = 0.029) and anteroposterior displacement (p = 0.007) than women.ConclusionsSmall variations in footwear drop can affect postural control, particularly in the medio-lateral plane. Sex and BMI significantly influence CoP behavior, suggesting the need to consider these factors in footwear design and clinical balance assessments.

The novel Next Step test is a reliable measure of anticipatory postural adjustments made by children with cerebral palsy prior to taking a step

Many pregnant women suffer from pelvic girdle pain (PGP) during pregnancy. Etiologies are multifactorial and affect the joint stability of the sacroiliac joint. Pelvic belts could restore stability and reduce pain during gait. The center of pressure (COP) is a reliable parameter to assess gait and balance. The objectives of this study were to analyze the COP during gait in pregnant women with PGP, to evaluate the effect of pelvic belts and to compare two types of belts on COP parameters. 46 pregnant women with PGP, 58 healthy pregnant women and 23 non-pregnant women participated in the study. The motor task consisted of three gait trials at different velocities on an electronic walkway. Two pelvic belts for pregnant women were used. An analysis of variance was performed to determine the effects of the progression of the pregnancy, gait speed, presence of pregnancy and occurrence of pain on the COP parameters. Compared to the control group, pregnant women with PGP had a higher stance time, but COP displacement and velocity were lower. The COP parameters varied between pregnant women with and without pelvic girdle pain, the use of a belt during pregnancy decreased the walking velocity. No difference was found according to the type of belt. Differences in COP parameters during gait between pregnant women with or without PGP were minimal. Pelvic girdle pain did not affect the center of pres- sure. Wearing a belt during pregnancy modified the center of pressure velocity during gait in pregnant women with PGP.

Background: The aim of this study was to compare postural control between Adolescents with Idiopathic Scoliosis (AIS) and healthy adolescents. Methods: In this cross-sectional study, 20 AIS adolescents with a right thoracic curvature between 10 and 45 degrees and 20 healthy adolescents were matched to compare postural control. Postural control assessments included Center of Pressure (COP) range and COP velocity in the Anteroposterior (AP) and Mediolateral (ML) directions, and the COP sway area in the standing position with opened eyes and closed eyes by the force plate. Results: This study showed that the postural control variables in AIS adolescents and healthy adolescents in terms of COP range, COP velocity, and COP sway area in standing positions with open and closed eyes were significantly different with those of AIS adolescents being worse than those of healthy adolescents (all p&lt;0.001). The interaction between Group and Condition (eyes open and eyes closed) was not significant for all variables (all p&gt;0.05). Conclusion: Differences in the postural control measures indicate postural instability in adolescents with AIS compared to healthy adolescents.