Center Of Pressure Mean Velocity Research Articles

Postural Control and Neuromuscular Activation in 11-13-Year-Old Athletic Boy Swimmers.

This study compared postural control and neuromuscular activation in athletic swimmers (A-S) and non-athletic swimmers (N-A-S) in older children. Ten A-S and ten N-A-S underwent assessments of center of pressure (CoP) parameters under static and dynamic surfaces in two directions (dynamic mediolateral (DML) and dynamic anteroposterior (DAP)) in eyes-open (EO) and eyes-closed (EC) conditions, and electromyography (EMG) parameters under DAP and DML directions in EO and EC conditions. Results showed that A-S demonstrated significantly superior postural control (p < 0.05), with smaller CoP area and lower CoP mean velocity compared with N-A-S, particularly in static with EC, DAP with EO and EC, and DML with EO conditions. A-S exhibited significantly larger neuromuscular activation amplitudes (p < 0.05), especially in the AP direction. These findings suggested that athletic swimming training may enhance postural control and neuromuscular activation in 11-13-year-old children, emphasizing the potential benefits of incorporating swimming exercises in these children.

Repeated exposure to virtual reality decreases reliance on visual inputs for balance control in healthy adults

Postural control may encounter acute challenges when individuals are immersed in a virtual reality (VR) environment, making VR a potential pertinent tool for enhancing balance capacity. Nonetheless, the effects of repeated exposure to VR on balance control remain to be fully elucidated. Fifty-five healthy participants stood upright for six bouts of 90 s each in an immersive virtual reality (VR) environment using a head-mounted display (repeated VR exposure). During these bouts, participants experienced simulated forward and backward displacements. Before and after the repeated VR exposure, the center of pressure mean velocity (VELCOP) was measured in response to simulated forward and backward displacement in VR, as well as during quiet upright standing with eyes open (EO) and closed (EC) in the real environment. The results revealed a significant decrease in VELCOP for forward and backward simulated displacements in both antero-posterior and medio-lateral directions (p < 0.01) after compared to before repeated VR exposure. Furthermore, VELCOP significantly decreased when participants stood upright in EC (−5%; p = 0.004), but not EO (+3%; p > 0.05) in the real environment after repeated VR exposure. The Romberg ratio (EC/EO) was reduced in both antero-posterior and medio-lateral directions (p < 0.05) after VR exposure. This study indicates that repeated exposure to VR induces changes in balance control in both virtual and real environments. These changes may be attributed, in part, to a reduction in the weighting of visual inputs in the multisensory integration process occurring during upright standing. Accordingly, these findings highlight VR as a potentially effective tool for balance rehabilitation. Significance statementThis study indicates that repeated exposure to VR induces changes in balance control in both virtual and real environments that can rely, in part, on a reduction in the weighting of visual inputs in the multisensory integration process occurring during upright standing.

Effect of Verbal Encouragement on Postural Balance in Individuals with Intellectual Disabilities.

This study investigated the effect of verbal encouragement (VE) on static and dynamic balance in individuals with intellectual disabilities (IDs). A total of 13 mild IDs and 12 moderate IDs participants underwent static balance tests (bipedal stance on firm surface, under open eyes (OEs) and closed eyes (CEs), and foam surface, unipedal stance on firm surface) and dynamic balance assessments (Y Balance Test (YBT) and Expanded Timed Up-and-Go Test (ETUGT)) under VE and no VE (NO/VE) conditions. VE significantly reduced center of pressure mean velocity (CoPVm) values for mild IDs in firm bipedal CEs conditions. The mild IDs group exhibited improved YBT scores and enhanced ETUGT performances for both groups under VE. Incorporating VE as a motivational strategy in balance training interventions can positively impact static and dynamic balance in individuals with mild IDs, especially in challenging conditions like unipedal stances on firm surfaces.

Trend change analysis in the assessment of body balance during posture adjustment in reaction to anterior-posterior ground perturbation.

Postural adjustments (PA) occur to counteract predictable perturbations and can be impaired as a result of musculoskeletal and neurological dysfunctions. The most common way to detect PA is through electromyography measurements or center of pressure (COP) position measurements, where analysis in time domain and frequency domain are the most common. Aim of the research was to determine whether a new method of analyzing stabilographic measurements-the COP trend change analysis (TCI) of temporary posture corrections- can expand understanding of changes in balance strategy connected with PA. The study group involved 38 individuals (27women, 11men) aged 23±2.6 years. Measurements were performed using a stabilographic platform placed on a perturbation platform. The tests involved three measurements with forward and backward momentary movements of the platform. Participants were tested in three conditions-knowing the nature, time and direction of perturbation (Tr3), knowing only the nature of perturbation (Tr2) and without any information about the perturbation (Tr1). Statistically significant differences were revealed in the last second of Tr3 for the mean velocity of COP (p<0.05) and for two TCI parameters-TCI_dV (p<0.05) and TCI_dS (p<0.01). The increase in TCI_dV was related to the increase in the mean distance between trend changes (TCI_dS) and constant value of the mean time between trend changes (TCI_dT). The increase of the mean value of TCI_dS was the result of smaller number of posture corrections with the distance 0-2 mm and lager number with the distance 4-6 mm. Obtained results proved that the TCI analysis is a method enabling an extended analysis of PA, indicating the nature of changes occurring in posture corrections-longer momentary jumps of COP-related to a change in the strategy of maintaining balance before a known disorder, which has not been analyzed in this type of research so far.

Do Motor-Cognitive and Motor-Motor Dual-Task Training Differently Affect Dual-Task Interference in Individuals With Intellectual Disability?

This study explored the effect of different dual-task (DT) training programs on DT interference in adults with intellectual disability. Center-of-pressure (CoP) mean velocity in single-task (ST) and cognitive-DT conditions and the Timed Up-and-Go Test (TUGT)during ST, cognitive-DT, and motor-DT conditions were assessed before and after intervention in a cognitive-motor training group, a motor-motor training group, and a control group. Before training, CoP mean velocity and TUGT time increased (p < .001) in DT compared with theST condition. After training, the CoP mean velocity values remained unchanged (p = .07) in DT compared with theST condition among the cognitive-motor training group. Furthermore, compared with the ST condition, no increase (p = 1) was reported in the TUGT time during the cognitive-DT condition for the cognitive-motor training group and during the motor-DT for the motor-motor training group (p = .12). The effect of DT training on DT interference depends on the training modality.

The Effects of Listening to Music on Postural Balance in Middle-Aged Women.

Listening to music has been found to influence postural balance in both healthy participants and certain patients, whereas no study investigates such effects among healthy middle-aged women. Thus, this study aimed to investigate the effect of music on postural balance in middle-aged women. Twenty-six healthy women aged between 50 and 55 years participated in this study. A stabilometric platform was used to assess their postural balance by recording the mean center of pressure velocity (VmCOP) in the eyes-opened (OE) and -closed (EC) conditions on both firm and foam surfaces. Our results showed that listening to an excerpt of Mozart's Jupiter significantly decreased the VmCOP values in two sensory conditions (firm surface/EO: (p < 0.01; 95% CI: 0.27 to 2.22); foam surface/EC: (p < 0.001; 95% CI: 0.48 to 2.44)), but not in the other two conditions (firm surface/EC and foam surface/EO). We concluded that listening to Mozart's symphony improved postural performance in middle-aged women, even in challenged postural conditions. These enhancements could offer great potential for everyday functioning.

Dynamic postural control in women athletes with and without nonspecific low back pain with high and low pain-related anxiety- A case-control study

BackgroundLow back pain is common among athletes and it has been shown that postural control is altered in the general population with nonspecific low back pain (NSLBP). Psychological factors may also predispose individuals to risk of altered postural control. Dynamic postural control is essential to the performance of athletes. This study aimed to compare the dynamic postural control between women athletes with and without NSLBP with high and low pain-related anxiety.MethodsForty-five female athletes (15 NSLBP with high pain-related anxiety, 15 NSLBP with low pain-related anxiety, and 15 healthy (control)) were included. Pain-related anxiety was assessed using the Pain Anxiety Symptom Scale-20 (PASS-20). Based on the cut-off score of 30 for the total score of PASS-20, NSLBP patients were classified into two groups of low and high pain-related anxiety. Participants performed double-leg vertical drop jump (DVJ) and single-leg vertical jump (SVJ) tests on a Kistler force plate (type 9260AA6, Kistler Instruments Inc, Switzerland). The total root mean square (RMS) of the center of pressure (COP), COP displacement in the anteroposterior (AP), and mediolateral (ML) directions, COP mean velocity, and time to stabilization (TTS) in vertical, AP, and total directions were extracted from COP and ground reaction force data using MATLAB software. One-way Analysis of variance (ANOVA) and Welch’s ANOVA were employed to compare the groups. In case of significant findings, post hoc tests were performed.ResultsThe results showed that during DJV, athletes with high pain-related anxiety had significantly greater TTS in all total, AP, and ML directions than other groups (P < 0.05). Also, the control group showed greater total RMS distance during DJV than either NSLBP group. However, no significant differences in TTS and COP parameters were found between the groups during SVJ (P > 0.05).ConclusionsThe findings suggest that pain-related anxiety may contribute to athletes’ postural control strategies. Therefore, it is important to consider the level of pain-related anxiety during planning postural control exercises for women athletes with NSLBP.

The Influence of Listening to Preferred versus Non-Preferred Music on Static and Dynamic Balance in Middle-Aged Women.

Although many women perform postural tasks while listening to music, no study has investigated whether preferred music has different effects than non-preferred music. Thus, this study aimed to explore the effects of listening to preferred versus non-preferred music on postural balance among middle-aged women. Twenty-four women aged between 50 and 55 years were recruited for this study. To assess their static balance, a stabilometric platform was used, recording the mean center of pressure velocity (CoPVm), whereas the timed up and go test (TUGT) was used to assess their dynamic balance. The results showed that listening to their preferred music significantly decreased their CoPVm values (in the firm-surface/eyes-open (EO) condition: (p < 0.05; 95% CI [-0.01, 2.17])). In contrast, when the women were listening to non-preferred music, their CoPVm values significantly (p < 0.05) increased compared to the no-music condition in all the postural conditions except for the firm-surface/EO condition. In conclusion, listening to music has unique effects on postural performance, and these effects depend on the genre of music. Listening to preferred music improved both static and dynamic balance in middle-aged women, whereas listening to non-preferred music negatively affected these performances, even in challenged postural conditions.

Does vibration frequency and location influence the effect of neck muscle vibration on postural sway? A cross-sectional study in asymptomatic participants.

Postural control is of utmost importance for human functioning. Cervical proprioception is crucial for balance control. Therefore, any change to it can lead to balance problems. Previous studies used neck vibration to change cervical proprioception and showed changes in postural control, but it remains unknown which vibration frequency or location causes the most significant effect. Therefore, this study aimed to investigate the effect of different vibration frequencies and locations on postural sway and to serve as future research protocol guidance. Seventeen healthy young participants were included in the study. We compared postural sway without vibration to postural sway with six different combinations of vibration frequency (80, 100, and 150Hz) and location (dorsal neck muscles and sternocleidomastoid). Postural sway was evaluated using a force platform. The mean center of pressure (CoP) displacement, the root mean square (RMS), and the mean velocity in the anteroposterior and mediolateral direction were calculated, as well as the sway area. The aligned rank transform tool and a three-way repeated measures ANOVA were used to identify significant differences in postural sway variables. Neck vibration caused a significant increase in all postural sway variables (p < 0.001). Neither the vibration frequency (p > 0.34) nor location (p > 0.29) nor the interaction of both (p > 0.30) influenced the magnitude of the change in postural sway measured during vibration. Neck muscle vibration significantly changes CoP displacement, mean velocity, RMS, and area. However, we investigated and found that there were no significant differences between the different combinations of vibration frequency and location.

Center of Pressure Behavior in Response to Unexpected Base of Support Shifting: A New Objective Tool for Dynamic Balance Assessment.

The translation of the base of support represents a promising approach for the objective assessment of dynamic balance control. Therefore, this study aimed to present a servo-controlled, electrically driven movable plate and a new set of parameters based on the center-of-pressure (CoP) trajectory. Twenty subjects were assessed on a force platform screwed over a movable plate that could combine the following settings: direction (forward (FW) and backward (BW)), displacement (25 mm, 50 mm, and 100 mm), and ramp rate (100 mm/s and 200 mm/s). The subjects underwent two sets of 12 trials randomly combining the plate settings. From the CoP trajectory of the 2.5 s time window after the perturbation, the 95% confidence-interval ellipse (Area95) and the CoP mean velocity (Unit Path) were calculated. Within the same time window, the first peak (FP), the maximal oscillations (ΔCoPMax), and the standard deviation (PPV) of the CoP anterior-posterior trajectory were calculated. The plate direction (p < 0.01), ramp rate (p < 0.001), and displacement (p < 0.01) affected the Area95, FP, and ΔCoPMax, while the Unit Path and PPV were influenced only by the ramp rate (p < 0.001) and displacement (p < 0.001). The servo-controlled, electrically driven movable plate and the CoP-related parameters presented in this study represent a new promising objective tool for dynamic balance assessment.

Postural balance and body mass index in older adults; a descriptive and associative study testing traditional risk factors.

There is a scarcity of information about how much the postural balance parameters, as the area and mean velocity of the center of pressure (CoP), can be modified by traditionally adiposity markers in older adults. To describe and associate postural balance parameters in Chilean older adults with different BMI. A second objective was to associate the area of balance with weight. In a descriptive study, Chilean older adults (mean age; 70 ± 1.0, BMI 29.0 ± 0.4 kg/m2) were categorized by a normoweight control group (CG, n = 7, BMI; 23.1 ± 0.5), overweight (OvW, n = 41, BMI; 27.6 ± 0.2), and obesity (Ob, n = 23, BMI; 34.2 ± 0.5). The subjects were evaluated on a stable/hard [HS]/soft [SS] surface, and under open [OE]/ closed [CE] eyes. Secondary outcomes were weight, height, BMI, and functional health. Univariate test and linear regression were applied. CoP mean velocity on the HS and CE, showed significant differences between CG vs. OvW groups (24.9 ± 7.4 mm/s vs. 12.1 ± 0.97 mm/s, p < 0.0001). There were significant differences in Romberg index between CG vs. OvW group (176.7 ± 16.4% vs. 132.4 ± 7.1%, p = 0.002), and between CG vs. Ob group (176.7 ± 16.4% vs. 129.4 ± 17.2%, p = 0.005). On the SS with OE, there were significant differences between CG vs. OvW groups (29.8 ± 4.8 mm/s vs. 18.6 ± 1.2 mm/s, p < 0.003), and, on the SS, with CE, between CG vs. OvW groups (41.5 ± 31.2 mm/s vs. 24.6 ± 15.2 mm/s, p = 0.015). At higher BMI such as at overweight or obesity conditions, older adults show a reduced 'CoP mean velocity' than control normoweight peers', being 'weight' a traditional adiposity risk factor predictor of balance performance.

Exploring the relationship of static and dynamic balance with muscle mechanical properties of the lower limbs in healthy young adults.

There is emerging evidence that mechanical properties of in vivo muscle tissues are associated with postural sway during quiet standing. However, it is unknown if the observed relationship between mechanical properties with static balance parameters generalise to dynamic balance. Thus, we determined the relationship between static and dynamic balance parameters with muscle mechanical properties of the ankle plantar flexors [lateral gastrocnemius (GL)] and knee extensors [vastus lateralis (VL)] in vivo. Twenty-six participants (men = 16, women = 10; age = 23.3 ± 4.4years) were assessed for static balance [centre of pressure (COP) movements during quiet standing], dynamic balance (reach distances for the Y-balance test) and mechanical properties (stiffness and tone) of the GL and VL measured in the standing and lying position. Significant (p < .05) small to moderate inverse correlations were observed between the mean COP velocity during quiet standing with stiffness (r = -.40 to -.58, p = .002 to .042) and tone (r = -0.42 to -0.56, p = 0.003 to 0.036) of the GL and VL (lying and standing). Tone and stiffness explained 16%-33% of the variance in the mean COP velocity. Stiffness and tone of the VL measured in the lying (supine) condition were also inversely significantly correlated with Y balance test performance (r = -0.39 to -0.46, p = 0.018 to 0.049). These findings highlight that individuals with low muscle stiffness and tone exhibit faster COP movements during quiet standing, indicative of reduced postural control but also reveal that low VL stiffness and tone are associated with greater reach distances in a lower extremity reaching task, indicative of greater neuromuscular performance.

Could Electromyographic and Pressure Related Signals Identify Differences in Abdominal Activity and Postural Control between Women with and without C-Section?

Scars interfere with the motor system; however, the influence of c-section scars has not been described yet. The aim of this study is to relate the presence of abdominal scars from a caesarean section with changes in postural control-stability and orientation and abdominal and lumbar neuromuscular control in the orthostatic position. Cross-sectional analytical observational study comparing healthy primiparous women with caesarean delivery (n = 9) and physiologic delivery (n = 12) who have delivered more than one year before. The relative electromyographic activity of the rectus abdominis, transverse abdominis/oblique internus and lumbar multifidus muscles, antagonist co-activation, the ellipse area, amplitude, displacement, velocity, standard deviation, and spectral power of the centre of pressure, and thoracic and lumbar curvatures, were evaluated in the standing position in both groups, through an electromyographic system, a pressure platform and spinal mouse system. In the "caesarean delivery" group, scar mobility was evaluated using a modified adheremeter. Significant differences in CoP medial-lateral velocity and mean velocity were observed between groups (p < 0.050), while no significant differences were in the level of muscle activity, antagonist co-activation, and thoracic and lumbar curvatures (p > 0.05). The information provided by the pressure signal seems to identify postural impairments in women with c-sections.

Early Changes in Postural Balance Following Inverted V-Shaped High Tibial Osteotomy in Patients With Knee Osteoarthritis

Patients with knee osteoarthritis and varus knee deformity have impaired postural balance, resulting in decreased walking performance and an increased risk of falls. This study aimed to investigate the early changes in the postural balance following inverted V-shaped high tibial osteotomy (HTO). Fifteen patients with medial knee osteoarthritis were recruited. Postural balance was assessed using the center-of-pressure (COP) data during single-leg standing before and 6weeks after inverted V-shaped HTO. The maximum range, mean velocity, and area of COP movements in the anteroposterior and mediolateral directions were analyzed. Preoperative and postoperative visual analog scale for knee pain was assessed. The maximum range of COP in the mediolateral direction decreased (P = .017), whereas the mean velocity of COP in the anteroposterior direction increased 6weeks postoperatively (P = .011). The visual analog scale score for knee pain significantly improved at 6weeks postoperatively (P = .006). Valgus correction with inverted V-shaped HTO resulted in improved postural balance in the mediolateral direction and good short-term clinical outcomes early following surgery. Early rehabilitation after inverted V-shaped HTO should focus on postural balance in the anteroposterior direction.

Effects of Anaerobic Fatigue Induced by Sport-Specific Exercise on Postural Control in Highly-Trained Adolescent Road Cyclists

The aim of this study was to evaluate whether and how anaerobic fatigue induced by sport-specific exercise affects the postural control of highly-trained adolescent road cyclists. Twenty-three male athletes, aged 15–18 years, were included in the study. Postural control was assessed using the pedobarographic platform (bipedal upright stance, sequentially, with eyes open (EO) and closed (EC) for 60 s each, with a 30 s interval), before and 3 min after a 30 s all-out effort performed on the ergometer. The results showed significant increases in the 95%-confidence ellipse area (p-value 0.000 and 0.001 for EO and EC, respectively), as well as centre-of-pressure (CoP) range displacement in the anteroposterior (p-value 0.000 for both EO and EC) and mediolateral (p-value 0.011 and 0.001 for EO and EC, respectively) planes. In addition, a significant decrease in CoP mean sway frequency was observed (p-value 0.000 and 0.001 for EO and EC, respectively), but no changes were noted in CoP mean velocity (p-value 0.316 and 0.670 for EO and EC, respectively). In our study, it has been indicated that anaerobic fatigue induced by sport-specific exercise deteriorates postural control in adolescent cyclists. Moreover, cycling training may affect the quality of postural corrective reactions occurring in response to anaerobic fatigue.

Effects of Posterior Spinal Correction and Fusion on Postural Stability in Patients with Adolescent Idiopathic Scoliosis

The present study aimed to assess the effects of posterior spinal correction and fusion on postural stability in patients with adolescent idiopathic scoliosis (AIS). The study included 41 female patients with AIS at our institution. All patients performed three 10 s single-leg standing trials on a force plate. The center of pressure (COP) was measured preoperatively, and at 1 week and 6 months postoperatively. The postural stability parameters were absolute minimum time-to-boundary (TTB), mean of the minimum TTB, mean COP velocity, standard deviation, range, and 95% confidence ellipse area. One-way repeated analysis of variance or Friedman test was applied to the postural stability parameters. Multiple comparisons were performed using the Bonferroni correction. The absolute minimum TTB and the mean minimum TTB showed a significant increase 6 months post-operation as compared to preoperatively and 1 week postoperatively. The COP velocity significantly decreased at 6 months post-operation compared to preoperatively and 1 week postoperatively. These changes in postural stability indicate that spinal correction and fusion can be considered to improve postural stability during single-leg standing tests in the postoperative period.

Swimming, better than tennis, develops sensorimotor adaptabilities involved in postural balance in 5-6-year-old children

Purpose The present study aimed to evaluate the postural balance of young tennis players and young swimming practitioners in static and dynamic conditions. Methods Thirty-six children (5–6 years old) participated in 3 groups: 12 tennis players, 12 swimming practitioners and 12 controls. Static and dynamic [in medial lateral (ML) and anterior posterior (AP) planes] postural balance were assessed by the centre of pressure sways using a stabilometric force platform in the eyes opened (EO) and eyes closed (EC) conditions. Results In the EO condition, swimming practitioners and tennis players had a significantly lower (p < 0.05) centre of pressure mean velocity (CoPVm) compared to controls in both static and dynamic medial-lateral (D-ML) postures. In the D-ML posture, swimming practitioners showed lower CoPVm compared to tennis players. However, in the EC condition, only the swimming practitioners showed better static and D-ML postural balance (p < 0.05) compared to their counterparts. In the static posture, the Romberg index value was significantly higher (p < 0.05) in tennis players compared to the two other groups. Conclusion Tennis players developed a higher reliance on vision to maintain balance, whereas swimming practitioners were more stable in challenging postural conditions. Clinicians should consider incorporating swimming training rather than tennis as an appropriate balance training in fall-prevention programs.

Effects of Music Listening on Postural Balance in Adolescents with Visual Impairment.

We aimed to investigate the effect of music on visually impaired adolescents' postural balance across different somatosensory and vestibular input conditions. We recruited 19 adolescent participants (9 males, 10 females) with severe congenital visual impairment. We recorded their mean center of pressure velocity (CoPVm) during static upright bipedal standing under somatosensory (firm and foam surfaces) and vestibular (head facing forward (HFF), head rotated 90° to the right (HRR), and head rotated 90° to the left (HRL)) perturbations in three auditory conditions (no-music, listening to Jupiter, and listening to their preferred music). We found that CoPVm decreased significantly when listening to both Jupiter and preferred music, compared to the no-music condition on both firm (p < .05) and foam (p < .001) surfaces and with the HFF (p < .05), rotated to the right (p < .001) or rotated to the left (p < .001). Moreover, CoPVm values increased significantly with somatosensory manipulation (p < .001) in all the auditory conditions and with vestibular manipulation (p < .01) only in the no-music condition. We concluded that listening to both Jupiter and preferred music improved postural balance in visually impaired adolescents, even in challenged postural conditions.

Validity and reliability of center of pressure measures to quantify trunk control ability in individuals after stroke in subacute phase during unstable sitting test

ObjectiveThe objective of this study was to assess, for individuals with hemiparesis after a stroke in subacute phase, the validity and reliability of center of pressure (CoP) parameters measured during sitting balance on an unstable support. Materials and methodsThirty-two individuals after stroke were included in this observational study for validity and reliability (mean age: 64.34 ± 9.30y, 23 men, mean post-stroke duration: 55.64 ± 27days). Intra-Class Correlation (ICC) and Bland Altman plot assessed intra-rater reliability and inter-rater reliability of CoP parameters during unstable sitting balance test (anteroposterior or mediolateral imbalance). Validity was established by correlating CoP parameters with the Modified Functional Reach Test, trunk strength, Balance Assessment in Sitting and Standing and Timed Up and Go tests. ResultsThe findings highlighted significant correlations between CoP parameters and trunk strength for anteroposterior seated destabilization. Good to excellent intra and inter-rater reliability (0.87 ≤ ICC ≤ 0.95) was observed for all CoP length parameters and CoP mean velocity in both mediolateral and anteroposterior imbalance conditions. CoP parameters for mediolateral unstable sitting condition were more reliable than for anteroposterior instability. ConclusionTrunk control assessment during unstable sitting position on a seesaw is a reliable test for assessing trunk control ability in individuals after a stroke. CoP length and mean velocity are found to be the best parameters.

TEST–RETEST RELIABILITY OF POSTURAL SWAY MEASURES DURING STATIC STANDING BALANCE PERFORMANCE IN HEALTHY ELDERLY ADULTS

Little is known about the reliability of postural sway measures in healthy elderly adults. Moreover, there is no standardized balance test protocols such as an efficient number of repeated measurements for older people. Therefore, we investigated test-retest reliability of center of pressure (COP) variables during static balance performance in elderly adults. Twenty-five elderly adults (15 elderly men and 10 elderly women) were asked to perform quiet standing balance test on a self-developed force platform. COP-based variables, i.e., COP mean distance, sway area, mean velocity, mean frequency, maximum frequency, and maximum power amplitude were derived from the COP data. For the test-retest reliability of each COP-based variable, intraclass correlation coefficient (ICC) was assessed in two-trials and three-trials of balance test. Mean velocity showed the highest ICC values in all directions (ICC = 0.832–0.922). Frequency domain variables presented lower reliability than time domain variables. Additionally, elderly adults did not affect the number of repeated measurements in most postural balance variables. These results suggest that time domain variables are more reliable variables than frequency domain variable and that balance test of two trials might be rather effective for elderly adults. These findings can be used to develop an optimal protocol of static balance test and select postural balance variables for elderly adults.