Search

Active video games (AVG) have been used as training tools and are known to ameliorate balance performance in children with Developmental Coordination Disorder (DCD). Our aim was to evaluate balance using clinical tests and by measuring body sway using a force plate with a mixed design of vision (eyes open/eyes closed), surface (rigid/soft). and support (stance/semitandem) before, and after, training and 4 months later (follow-up). Thirty-six DCD children and 40 typically developing children participated in the study, of which 50 children (26 DCD; 24 typically developing) were retested after 4 months. Balance improved on the clinical measures after the training, which was independent of type of AVG (Wii-Fit and Xbox Kinect) used, and this effect was still present after 4 months. The AVG training did not influence general sway behavior, but only sway in the eyes-open condition. corresponding with task demands of the training and indicating a training-specific effect. Overall, DCD children and typically developing children responded comparably to the AVG training, thereby maintaining the gap in performance between the two groups. The changes iii postural sway are interpreted as a sign of more confidence and less freezing of the joints, enabling greater flexibility of movements and balance strategies as supported by the improved performance on balance tests in the DCD children. This is the first study that showed long-term effects of AVG training on balance performance. However. these follow-up results should be interpreted with caution given that 35% of the children were lost in follow-up. [ABSTRACT FROM AUTHOR]

A force plate is mainly used in biomechanics; it aims to measure the ground reaction force in a persons walking or standing position. In this study, a large-area force mat of the piezoresistance sensing type was developed, and a deep-learning-based weight measurement calibration method was applied to solve the problem in which measurements are not normalized because of physical limitations in hardware and signal processing. The test set was composed of the values measured at each point by weight and the value of the center of the pressure variable, and the measured value was predicted using a deep neural network (DNN) regression model. The calibration verification results show that the average weight errors range from a minimum of 0.06% to a maximum of 3.334%. This is simpler than the previous method, which directly measures the ratio of the resistance value to the measured weight of each sensor and derives an equation.

To evaluate the concurrent validity and test–retest reliability of common movement, strength, and balance tests using portable uniaxial dual force plates. Repeated measures cross-sectional study. Sixteen healthy individuals participated in two testing sessions, where they performed 12 different movement, strength, and balance tests. Vertical ground reaction force and centre of pressure data were collected using the VALD ForceDecks simultaneously with ground-embedded laboratory force plates. Concurrent validity was assessed using root mean square error for raw time-series data and Bland–Altman plots for discrete metrics. Test–retest reliability was assessed using intraclass correlation coefficients and minimal detectable changes. ForceDecks recorded vertical ground reaction forces and center of pressure with high accuracy compared to laboratory force plates. The mean bias between systems was negligible (<2 N or 0.1 mm), with small limits of agreement (<5 N or 1 mm). Overall, 530/674 (79%) showed good or excellent validity (<10% difference) and 611/773 (79%) had good or excellent reliability (intraclass correlation coefficient >0.75). ForceDecks reliability was similar to laboratory force plates (<0.07 intraclass correlation coefficient median difference for all metrics). Portable uniaxial force plates record highly accurate vertical ground reaction forces and center of pressure during a range of movement, strength, and balance tests. The VALD ForcDecks are a valid and reliable alternative to laboratory force plates when strict standardized testing and data analysis procedures are followed. Users should be aware of the validity and reliability characteristics of the tests and metrics they choose. [ABSTRACT FROM AUTHOR]

Assessing postural control is important for the assessment of motor function after concussion. Data used for postural control assessment typically do not take the sport played, age, or sex of the athlete into consideration. It is plausible these variables may be significant when making return-to-play decisions. This study used the BTrackS database to examine differences in postural control in athletes playing different types of sports and across sex and age. BTrackS data from 9093 high school to college-aged athletes (aged 14–22 years) were examined employing a One-way ANOVA with a post-hoc test to compare CoP path length between sport types. A moderation analysis was used to test interaction effects of sex and age on a CoP/BMI ratio. Significant differences were observed between sport types, F(3,9089) = 42.4, p <.001, η2 = 0.014. Post hoc tests indicated that collision (M = 25.0, SD = 7.6) sport athletes exhibited significantly higher CoP measures compared to the contact (M = 23.4, SD = 7.4), limited contact (M = 22.9, SD = 6.9), and non-contact (M = 23.0, SD = 7.4) athletes. There was no difference between other sport types (p >.20). A significant mean sex difference (Mmale = 0.924, Mfemale = 0.898, p <.001) and a quadratic association with age, (β = −0.042, p <.001) was observed. Further, magnitude of those age differences decreased with age (β = 0.011, p <.001). An interaction of age and sex was significant for linear (β = 0.020, p <.001) and quadratic terms (β = −0.006, p <.001). Athletes exhibited different postural control when the type of sport, age, and sex was taken into consideration. This data possess clinical significance as this suggests that normative postural control data for collision sport athletes should be derived from data based upon type of sport played, age, and sex of the athlete. • Over 9000 balance tests were analyzed, based on frequency and level of contact. • Balance data used for return-to-play decisions should be from similar sports. • Collision sports athletes display significantly different balance performance. [ABSTRACT FROM AUTHOR]

Preterm infants are more likely to demonstrate developmental delays than fullterm infants. Postural measurement tools may be effective in measuring the center of pressure (COP) and asymmetry, as well as predicting future motor impairment. The objective of this systematic review was to evaluate existing evidence regarding use of pressure mats or force plates for measuring COP and asymmetry in preterm infants, to determine how measures differ between preterm and fullterm infants and if these tools appropriately predict future motor impairment. The consulted databases included PubMed, Embase, Scopus, and CINAHL. The quality of the literature and the risk of bias were assessed utilizing the ROB2: revised Cochrane risk-of bias tool. Nine manuscripts met the criteria for review. The postural control tools included were FSA UltraThin seat mat, Conformat Pressure-Sensitive mat, Play and Neuro-Developmental Assessment, and standard force plates. Studies demonstrated that all tools were capable of COP assessment in preterm infants and support the association between the observation of reduced postural complexity prior to the observation of midline head control as an indicator of future motor delay. Postural measurement tools provide quick and objective measures of postural control and asymmetry. Based on the degree of impairment, these tools may provide an alternative to standardized assessments that may be taxing to the preterm infant, inaccessible to therapists, or not sensitive enough to capture motor delays. [ABSTRACT FROM AUTHOR]

A force plate is a device that measures the ground reaction force caused by a shift in the human body's center of mass (CoM). Using a controlled change in the human body's CoM, the human body's center of pressure (CoP) is shifted in a 2D plane, along with an acceleration of the CoM along the plane perpendicular to the force plate, which allows for a generation of reference values for game control. In this paper, the development and validation of a system for game control based on a force plate are described. The game control system consists of a force plate, an electronic board used for measuring and PC communication via USB, and a PC application for data acquisition, system calibration, and game control. Based on the measured values of the player's CoP and the CoM acceleration along a plane perpendicular to the force plate, the game control system simulates pressing the UP, DOWN, RIGHT, LEFT, and SPACE keyboard keys or moving the mouse and clicking the left mouse button, which allows players to control simple games. A mathematical model has been developed for the game control system which includes running system calibration procedures in the system for each individual player. The mechatronic game control system is described in detail, and experiments were run on said system for the purpose of system validation. [ABSTRACT FROM AUTHOR]

Context: Static postural control deficits are commonly documented among individuals with chronic ankle instability (CAI). Evidence suggests individuals with CAI who seek medical attention after an ankle sprain report fewer subjective symptoms. It is unknown if seeking medical attention and receiving supervised physical rehabilitation has a similar effect on objective outcomes, such as static postural control. Objective: To compare measures of single-limb postural control and center of pressure (COP) location between participants with CAI who did or did not self-report attending supervised rehabilitation at the time of their first lateral ankle sprain. Design: Retrospective cohort. Setting: Laboratory. Patients (or Other Participants): Twenty-nine participants with CAI who did (n = 14) or did not (n = 15) self-report attending supervised rehabilitation. Intervention(s): Self-reported attendance or not of supervised rehabilitation at the time of initial injury. Main Outcome Measures: Participants performed three 20-second trials of single-limb stance on a force plate with eyes open. Main outcome measures included the COP velocities, time-to-boundary (TTB) absolute minima, mean of TTB minima, and SD of TTB minima in the anteroposterior and mediolateral directions. The spatial distribution of the COP data points under the foot was quantified within 4 equally proportional sections labeled anteromedial, anterolateral, posteromedial, and posterolateral. Results: Participants who reported attending supervised rehabilitation after their initial ankle sprain had a lower COP velocity in the anterior–posterior direction (P =.030), and higher TTB anterior–posterior absolute minimum (P =.033) and mean minima (P =.050) compared with those who did not attend supervised rehabilitation. Conclusions: Among individuals with CAI, not attending supervised rehabilitation at the time of initial injury may lead to worse static postural control outcomes. Clinicians should continue advocating for patients recovering from an acute ankle sprain to seek medical attention and provide continued care in the form of physical rehabilitation. [ABSTRACT FROM AUTHOR]

AbstractPostural stability is a crucial aspect of human balance and equilibrium. One way to quantify postural stability is by analyzing variations in the center of pressure under the feet. However, there are several factors involved in quantifying postural stability, and interpreting the information they provide can be challenging, especially in the context of pathological motion. The aim of this work is to reduce the confounding effects of these factors to the extent that measurable differences in results are primarily due to a pathological condition rather than secondary factors such as procedural variations. Materials and methods: The initial research conditions were established based on theoretical aspects of human standing stability. Thirteen normal subjects (5 female and 8 male) with a mean age of 21 ± 4.97 years and a mean BMI of 25.27 ± 4.53 kg/m2 were recruited for the study. Four investigations were conducted, including eyes closed-closed base, eyes open-closed base, eyes closed-open base, and eyes open-open base conditions. Data collection was performed using the AMTI AccuGait force plate and Balance Clinic software. Spectral characteristics, composite multiscale entropy, and conventional stability parameters were computed for both the anterior-posterior (AP) and medial-lateral (ML) directions. Results: Composite multiscale entropy shows no significant difference (p > 0.05) in both AP and medial-lateral (ML) directions. Whereas the frequency of oscillations in ML is more sensitive than other parameters with relatively large effect size (>0.9). Conclusion: The resulting set of variables provides a broad range of options for selecting specific variables related to a particular study topic. The benefit of this method is that it standardizes the analysis of the center of pressure and enables the comparability of variables gathered during various research measurements. For general standing stability measurements, composite multiscale sampling entropy is the most relevant factor that can be used to discriminate the stability state in both the anterior-posterior and medial-lateral directions.

A force plate is mainly used in biomechanics; it aims to measure the ground reaction force in a person’s walking or standing position. In this study, a large-area force mat of the piezoresistance sensing type was developed, and a deep-learning-based weight measurement calibration method was applied to solve the problem in which measurements are not normalized because of physical limitations in hardware and signal processing. The test set was composed of the values measured at each point by weight and the value of the center of the pressure variable, and the measured value was predicted using a deep neural network (DNN) regression model. The calibration verification results show that the average weight errors range from a minimum of 0.06% to a maximum of 3.334%. This is simpler than the previous method, which directly measures the ratio of the resistance value to the measured weight of each sensor and derives an equation.

Walking gait data acquired with force platforms may be used for person re-identification (re-ID) in various authentication, surveillance, and forensics applications. Current force platform-based re-ID systems classify a fixed set of identities (IDs), which presents a problem when IDs are added or removed from the database. We formulated force platform-based re-ID as a deep metric learning (DML) task, whereby a deep neural network learns a feature representation that can be compared between inputs using a distance metric. The force platform dataset used in this study is one of the largest and the most comprehensive of its kind, containing 193 IDs with significant variations in clothing, footwear, walking speed, and time between trials. Several DML model architectures were evaluated in a challenging setting where none of the IDs were seen during training (i.e., zero-shot re-ID) and there was only one prior sample per ID to compare with each query sample. The best architecture was 85% accurate in this setting, though an analysis of changes in walking speed and footwear between measurement instances revealed that accuracy was 28% higher on same-speed, same-footwear comparisons, compared to cross-speed, cross-footwear comparisons. These results demonstrate the potential of DML algorithms for zero-shot re-ID using force platform data, and highlight challenging cases. [ABSTRACT FROM AUTHOR]

Standing up from a chair is a mechanically demanding daily motion, and its biomechanics represent motor performance. In older adults with locomotive syndrome (LS), sit-to-stand (STS) movement with adequate postural control is essential to prevent falls. This study evaluated the characteristics of dynamic balance during STS movement on older adults with LS. A total of 116 participants aged ≥65 years were divided into Non-LS, LS stage 1, and LS stage 2 groups using the LS risk test. The participants were instructed to stand on the Nintendo Wii Balance Board as quickly as possible, and the STS movement was quantified using the vertical ground reaction force (VGRF) and center of pressure (CoP). The STS score, which represented dynamic balance, was significantly different among the groups (p < 0.001). The rate of VGRF development was significantly lower in the LS stages 1 and 2 than in the Non-LS group (p < 0.001). On the other hand, the total distance of the CoP path did not differ among the groups (p = 0.211). These findings indicated a reduction of postural control in older adults with LS. The STS score emphasized the importance of balance training to prevent falls in older adults with LS. [ABSTRACT FROM AUTHOR]

Preterm infants are more likely to demonstrate developmental delays than fullterm infants. Postural measurement tools may be effective in measuring the center of pressure (COP) and asymmetry, as well as predicting future motor impairment. The objective of this systematic review was to evaluate existing evidence regarding use of pressure mats or force plates for measuring COP and asymmetry in preterm infants, to determine how measures differ between preterm and fullterm infants and if these tools appropriately predict future motor impairment. The consulted databases included PubMed, Embase, Scopus, and CINAHL. The quality of the literature and the risk of bias were assessed utilizing the ROB2: revised Cochrane risk-of bias tool. Nine manuscripts met the criteria for review. The postural control tools included were FSA UltraThin seat mat, Conformat Pressure-Sensitive mat, Play and Neuro-Developmental Assessment, and standard force plates. Studies demonstrated that all tools were capable of COP assessment in preterm infants and support the association between the observation of reduced postural complexity prior to the observation of midline head control as an indicator of future motor delay. Postural measurement tools provide quick and objective measures of postural control and asymmetry. Based on the degree of impairment, these tools may provide an alternative to standardized assessments that may be taxing to the preterm infant, inaccessible to therapists, or not sensitive enough to capture motor delays.

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. [ABSTRACT FROM AUTHOR]

Postural stability is a crucial aspect of human balance and equilibrium. One way to quantify postural stability is by analyzing variations in the center of pressure under the feet. However, there are several factors involved in quantifying postural stability, and interpreting the information they provide can be challenging, especially in the context of pathological motion. The aim of this work is to reduce the confounding effects of these factors to the extent that measurable differences in results are primarily due to a pathological condition rather than secondary factors such as procedural variations. Materials and methods: The initial research conditions were established based on theoretical aspects of human standing stability. Thirteen normal subjects (5 female and 8 male) with a mean age of 21 ± 4.97 years and a mean BMI of 25.27 ± 4.53 kg/m² were recruited for the study. Four investigations were conducted, including eyes closed-closed base, eyes open-closed base, eyes closed-open base, and eyes open-open base conditions. Data collection was performed using the AMTI AccuGait force plate and Balance Clinic software. Spectral characteristics, composite multiscale entropy, and conventional stability parameters were computed for both the anterior-posterior (AP) and mediallateral (ML) directions. Results: Composite multiscale entropy shows no significant difference (p > 0.05) in both AP and medial-lateral (ML) directions. Whereas the frequency of oscillations in ML is more sensitive than other parameters with relatively large effect size (>0.9). Conclusion: The resulting set of variables provides a broad range of options for selecting specific variables related to a particular study topic. The benefit of this method is that it standardizes the analysis of the center of pressure and enables the comparability of variables gathered during various research measurements. For general standing stability measurements, composite multiscale sampling entropy is the most relevant factor that can be used to discriminate the stability state in both the anterior-posterior and medial-lateral directions. [ABSTRACT FROM AUTHOR]

A force plate is a device that measures the ground reaction force caused by a shift in the human body’s center of mass (CoM). Using a controlled change in the human body’s CoM, the human body’s center of pressure (CoP) is shifted in a 2D plane, along with an acceleration of the CoM along the plane perpendicular to the force plate, which allows for a generation of reference values for game control. In this paper, the development and validation of a system for game control based on a force plate are described. The game control system consists of a force plate, an electronic board used for measuring and PC communication via USB, and a PC application for data acquisition, system calibration, and game control. Based on the measured values of the player’s CoP and the CoM acceleration along a plane perpendicular to the force plate, the game control system simulates pressing the UP, DOWN, RIGHT, LEFT, and SPACE keyboard keys or moving the mouse and clicking the left mouse button, which allows players to control simple games. A mathematical model has been developed for the game control system which includes running system calibration procedures in the system for each individual player. The mechatronic game control system is described in detail, and experiments were run on said system for the purpose of system validation.

Static balance tests are conducted in various clinics for diagnosis and treatment adjustment. As a result of population aging, the accessibility of these tests should be increased, in the clinic, and for remote patient examination. A number of publications have already conducted static balance evaluations using the sensors embedded in a smartphone. This study focuses on the applicability of using smartphone-based balance assessment on a large scale while considering ease of use, safety, and reliability. The Mon4t® app was used to acquire the postural motion using different smartphone devices, different smartphone locations, and various standing postures. The signals derived from the app were compared to the center of pressure displacement derived from a force plate. The results showed moderate to high agreement between the two methods, particularly at the tandem stance (0.69 ≤ r ≤ 0.91). Preliminary data collection was conducted on three healthy participants, followed by 50 additional healthy volunteers, aged 65+. The results demonstrated that the Mon4t app can serve as an accessible and inexpensive static balance assessment tool, both in clinical settings and for remote patient monitoring, which is key for enabling telehealth. [ABSTRACT FROM AUTHOR]

Background: A force plate is used to determine the ability to balance ability. However, only some medical centers or laboratories are equipped with force plates because they are costly so a low-cost force plate is required for home care or health care institutes. Few studies compare the reliability of postural sway measurements in terms of age. This study proposes a low-cost force plate to select reliable parameters to evaluate postural sway. Objectives: To determine the intra-rater reliability of a novel force plate and the effect of age difference on the intra-rater test-retest reliability for the center of pressure (COP). Methods: Forty participants were enrolled for this study: 20 youths and 20 older adults. Participants stood on a custom-made and low-cost force plate with eyes opened and eyes closed to measure COP-related parameters. The within-day test-retest reliability was measured at two sessions on the same day and the between-days reliability was measured on two different days. The COP-related parameters include the average velocity of COP, the average velocity in the antero-posterior and medio-lateral directions, the mean distance of COP and the mean distance in the antero-posterior and medio-lateral directions. An intra-class correlation coefficient test with one-way random model was performed to determine the reliability of different variables within-days and between-days. The results were presented in single measurement of intraclass correlation coefficient (ICC), the standard error of measurements, and the minimal detectable changes of each COP-related parameters. Results: The novel low-cost force plate demonstrates excellent reliability in terms of the COP velocity related parameters for within- and between-day measurements. The ICC of COP distance related parameters were good to excellent reliability for between-day measurements (range: 0.43–0.84). Older adults demonstrated excellent reliability in terms of the mean distance for antero-posterior and the results were better than those for younger participants for the eyes-opened and eyes-closed conditions. The reliability in terms of the mean distance for medio-lateral was poor to good for older adults (range: 0.38–0.55), and excellent for younger participants. Conclusion: The novel and low-cost force plate reliably measured balance and age affects the reliability of different COP variables, so the results of this study were pertinent to the selection of COP measures. [ABSTRACT FROM AUTHOR]

Background: A force plate is used to determine the ability to balance ability. However, only some medical centers or laboratories are equipped with force plates because they are costly so a low-cost force plate is required for home care or health care institutes. Few studies compare the reliability of postural sway measurements in terms of age. This study proposes a low-cost force plate to select reliable parameters to evaluate postural sway.Objectives: To determine the intra-rater reliability of a novel force plate and the effect of age difference on the intra-rater test-retest reliability for the center of pressure (COP).Methods: Forty participants were enrolled for this study: 20 youths and 20 older adults. Participants stood on a custom-made and low-cost force plate with eyes opened and eyes closed to measure COP-related parameters. The within-day test-retest reliability was measured at two sessions on the same day and the between-days reliability was measured on two different days. The COP-related parameters include the average velocity of COP, the average velocity in the antero-posterior and medio-lateral directions, the mean distance of COP and the mean distance in the antero-posterior and medio-lateral directions. An intra-class correlation coefficient test with one-way random model was performed to determine the reliability of different variables within-days and between-days. The results were presented in single measurement of intraclass correlation coefficient (ICC), the standard error of measurements, and the minimal detectable changes of each COP-related parameters.Results: The novel low-cost force plate demonstrates excellent reliability in terms of the COP velocity related parameters for within- and between-day measurements. The ICC of COP distance related parameters were good to excellent reliability for between-day measurements (range: 0.43–0.84). Older adults demonstrated excellent reliability in terms of the mean distance for antero-posterior and the results were better than those for younger participants for the eyes-opened and eyes-closed conditions. The reliability in terms of the mean distance for medio-lateral was poor to good for older adults (range: 0.38–0.55), and excellent for younger participants.Conclusion: The novel and low-cost force plate reliably measured balance and age affects the reliability of different COP variables, so the results of this study were pertinent to the selection of COP measures.

Poor postural balance has been related to falls in older people. Although fall rates increase with age, age-related declines in postural balance of older people are still unclear. The goal of this study was to investigate age-related changes in the static postural balance ability of Korean elderly adults. Three hundred and eighty-nine normal elderly adults with ages ranging from 57 years to 87 years participated in this study. All elderly adults were instructed to stand in their preferred natural stance on a self-developed force platform. As postural sway variables, peak frequency, mean frequency, mean velocity, and mean distance were calculated from the center of pressure (COP) trajectories in both the medio-lateral (ML) and antero-posterior (AP) directions. The mean velocity in the older-elderly was significantly faster compared to those of the other age groups particularly in the AP direction (p < 0. 0 5). In both the ML and AP directions, the older-elderly group showed a greater mean distance compared to the other age groups (p < 0. 0 5). Conversely, no significant age group differences were found in mean frequency and peak frequency (p > 0. 0 5). Our results mean that the older-elderly group showed postural balance with faster AP sway speed and overall sway size. The results of our study help in the understanding of age-related declines in postural balance for the prevention of falls and the development of a regression model for normative postural balance ability in Korean elderly adults. [ABSTRACT FROM AUTHOR]

Multiple studies have suggested that some associations exist between occlusal factors and postural alterations. Objectives: This study aimed to evaluate the effectiveness of a vibrotactile posture trainer device, comprised a wearable device containing an accelerometer sensor to measure the angle of the neck flexion (input) and provided real-time vibrotactile biofeedback (output) for postural balance among patients with malocclusion. Methods: Twenty-four subjects were divided in 3 groups based on occlusion and using Angle's classification. Each group consisted of 8 patients for class I, II and III malocclusion. The Posture Trainer System was used for feedback concerning neck flexion angles when higher than 15 degrees. A 4-week training program to adjust posture balance in 2 axes (flexion-extension, lateral-flexion) was applied in activities for daily living. The assessments in this study were comprised of neck flexion angles from the Posture Trainer System and the center of pressure (N.m) using a force plate. The effects of a vibrotactile posture trainer (baseline vs. post-training test) were evaluated using the paired t-test and were assumed to be significant at p

Background: Accurately measuring postural sway is an important part of balance assessment and rehabilitation. Although force plates give accurate measurements, their costs and space requirements make their use impractical in many situations. Objective: The work presented in this paper aimed to address this issue by validating a virtual reality (VR) headset as a relatively low-cost alternative to force plates for postural sway measurement. The HTC Vive (HTC Corporation) VR headset has built-in sensors that allow for position and orientation tracking, making it a potentially e ective tool for balance assessments. Methods: Participants in this study were asked to stand upright on a force plate (NeuroCom; Natus Medical Incorporated) while wearing the HTC Vive. Position data were collected from the headset and force plate simultaneously as participants experienced a custom-built VR environment that covered their entire field of view. The intraclass correlation coefficient (ICC) was used to examine the test-retest reliability of the postural control variables, which included the normalized path length, root mean square (RMS), and peak-to-peak (P2P) value. These were computed from the VR position output data and the center of pressure (COP) data from the force plate. Linear regression was used to investigate the correlations between the VR and force plate measurements. Results: Our results showed that the test-retest reliability of the RMS and P2P value of VR headset outputs (ICC: range 0.285-0.636) was similar to that of the RMS and P2P value of COP outputs (ICC: range 0.228-0.759). The linear regression between VR and COP measures showed significant correlations in RMSs and P2P values. Conclusions: Based on our results, the VR headset has the potential to be used for postural control measurements. However, the further development of software and testing protocols for balance assessments is needed. [ABSTRACT FROM AUTHOR]

Study design: This is a retrospective cohort with multiple regression modeling. Objective: The aim is to develop a new method for estimating cone of economy (CoE) using a force plate rather than traditional motion capture. Background: Currently, most spinal deformity surgeons rely on static radiographic parameters for alignment, balance, and outcomes data alongside patient-reported outcome measures. The CoE, the stable region of upright posture, can be objectively measured to determine the efficiency and balance of the spine. Motion capture technology is currently used to collect data to calculate CoE, but this requires expensive and complex equipment, which is a barrier to widespread adoption and clinical use of CoE measurements. Force plates, which measure pressure, are less expensive and can be used in a clinical setting. Methods: Motion capture and a force plate were used to quantify the CoE of 473 subjects (423 spinal surgical candidates; 50 healthy controls; 271 females; age: 58.60 ± 15.27; height: 1.69 ± 0.13; weight: 81.07 ± 20.91), and a linear multiple regression model was used to predict CoE using force plate data in a human motion laboratory setting. Patients were required to stand erect with feet together and eyes open in their self-perceived balanced and natural position for a full minute while measures of sway and center of pressure (CoP) were recorded. Results: The CoP variable regression model successfully predicted CoE measurements. The variables that were used to predict vertical CoE were CoP coronal sway, CoP sagittal sway, and CoP total sway in several combinations. The coefficient of determination for the head total sway model indicated a 87.0% correlation (F(3,469) = 1044.14, p < 0.001). The coefficient of determination for the head sagittal sway model indicated a 69.2% correlation (F(3,469) = 351.70, p < 0.001). The coefficient of determination for the head coronal sway model indicated a 85.2% correlation (F(3,469) = 899.27, p < 0001). Conclusion: Cone of economy was estimated from force plate data using center of pressure with high correlation without the use of motion capture in healthy controls and a variety of spine patients. This could lower the entry burden for measurement of the CoE in patients, enabling widespread use. This would provide surgeons objective global balance data, along with Haddas' CoE classification system, that could assist with surgical decision-making and facilitate objective monitoring surgical outcomes. [ABSTRACT FROM AUTHOR]

Daniel J Goble,1 Harshan Brar,1 Elise C Brown,2 Charles RC Marks,1 Harsimran S Baweja31Department of Human Movement Science, Oakland University, Rochester, MI, USA; 2Public and Environmental Wellness, Oakland University, Rochester, MI USA; 3School of Exercise and Nutritional Sciences, San Diego State University, San Diego, CA, USAPurpose: Force plate balance testing technology has traditionally been underutilized in clinical and research settings due to the high cost and lack of portability. A relatively new force plate called the Balance Tracking System (BTrackS) has been developed to overcome these barriers. BTrackS recently implemented the modified Clinical Test of Sensory Integration and Balance (mCTSIB) as a means of evaluating various sources of sensory information for postural sway control. The present study aimed to provide much needed normative data for the BTrackS mCTSIB protocol.Materials and methods: Data from 604 healthy adults (308 women; 296 men) between the ages of 18 and 29 years were collected according to the BTrackS mCTSIB protocol. The protocol consisted of four, 20-second static standing trials that manipulated relative contributions of the vision, proprioception and vestibular sensory systems through various eyes open/closed and foam/no foam conditions. Comparisons of men versus women and the impact of body size (ie body mass index) were determined so that relevant percentile rankings could be calculated.Results: Analysis of variance showed an interaction between sex and task condition on the BTrackS mCTSIB (p

Static balance tests are conducted in various clinics for diagnosis and treatment adjustment. As a result of population aging, the accessibility of these tests should be increased, in the clinic, and for remote patient examination. A number of publications have already conducted static balance evaluations using the sensors embedded in a smartphone. This study focuses on the applicability of using smartphone-based balance assessment on a large scale while considering ease of use, safety, and reliability. The Mon4t® app was used to acquire the postural motion using different smartphone devices, different smartphone locations, and various standing postures. The signals derived from the app were compared to the center of pressure displacement derived from a force plate. The results showed moderate to high agreement between the two methods, particularly at the tandem stance (0.69 ≤ r ≤ 0.91). Preliminary data collection was conducted on three healthy participants, followed by 50 additional healthy volunteers, aged 65+. The results demonstrated that the Mon4t app can serve as an accessible and inexpensive static balance assessment tool, both in clinical settings and for remote patient monitoring, which is key for enabling telehealth.

Differentiating scans without evidence of dopaminergic deficits (SWEDDs) from Parkinson's disease (PD) is very important to avoid costly and inappropriate interventions. The postural balance strategy patients with SWEDDs are not clear. This study investigates the difference in static postural balance between patients with SWEDDs and PD. Twenty-two patients (11 SWEDDs and 11 PD groups) and 11 control groups were instructed to quietly stand on a custom-made force platform. The outcome measures were, mean distance, 95% confidence ellipse area, mean velocity, mean frequency, peak frequency and peak power derived from the center of pressure (COP) data in overall, medio-lateral (ML) and anterio-posterior (AP) directions. As statistical analysis, ANOVA and post hoc tests were conducted for comparison of patients with SWEDDs and PD. SWEDDs patients presented a smaller postural sway size and a more frequent postural sway mainly in the ML direction (p < 0. 0 5). On the contrary, there were no significant differences in mean velocity and peak power. Also, no significant differences existed between SWEDDs and normal subjects (p > 0. 0 5). The results reflect that a few COP-based outcome variables might be useful to distinguish SWEDDs patients from PD patients. This study suggests that a static postural balance test can be used for clinical screening and identification of potential SWEDDs. [ABSTRACT FROM AUTHOR]

Portable force-measurement technologies are becoming increasingly popular tools to examine the maturation of postural motor milestones, such as sitting and standing, in infants. These convenient, low-cost devices provide numerous opportunities to characterize postural development outside of the laboratory. However, it is important to understand the unique challenges and technical limitations associated with collecting center of pressure (CoP) data using portable force-measurement technologies in infant populations. This study uses a mathematical model to examine issues that emerge when using portable force-measurement technologies to collect sitting and standing postural data in infants. The results of our mathematical simulations demonstrate that the CoP errors from portable force-measurement technologies depend on the posture examined (e.g., sitting vs. standing), the anthropometrics of the person (e.g., height and weight), the frequency of body sway, and the experimental setup (e.g., an additional support surface being placed on top of the device). Recommendations are provided for developmental researchers interested in adopting these technologies in infant populations. [ABSTRACT FROM AUTHOR]

Center of pressure (COP) has been one of the most popular index for balance evaluation in quiet standing. However, the balance evaluation based on COP has been limited due to its accuracy. For accurate balance evaluation, an estimation method of the center of mass (COM) from simple measuring devices is desirable. The purpose of this study is to estimate COM on sagittal plane from force plate measurement. One of the most popular method suggested in past studies is to integrate the COM acceleration estimated from shearing force on support surface, however, this technique requires appropriate boundary conditions. Instead of the integration method, we adopted a COM estimation method via gravity term in equation of angular motion. While the method can estimate COM in real time, an estimation error arose from the assumption of a single rigid body model. To clarify the estimation error in theory, we introduced a modal coordinate (rigid body mode and zero shearing force mode) in the analysis of double-link model. As a result, we found that the estimation accuracy decreases due to the influence of acceleration of zero shearing force mode. From a practical point of view, if the amplitude of COP and the ratio of zero shearing force mode is relatively small, COM can be estimated with high accuracy. Validation of the present method was verified by comparing COM from force plate measurement with that from motion capture measurement in stationary standing test and horizontally sway test.

Background: To better understand gait initiation in individuals with stroke and suggest possible training strategies, we compared the gait initiation of individuals with stroke and age-matched controls, and we examined the influence of different amounts of body weight support (BWS) during the execution of gait initiation in individuals with stroke.Materials and Methods: Twelve individuals with stroke and 12 age-matched controls initiated gait after a verbal command at a self-selected and comfortable speed, and individuals with stroke also initiated gait wearing a harness with 0%, 15%, and 30% of BWS. Length and velocity of the first step, distance between heels, and weight bearing in both lower limbs in the initial position were calculated. We also assessed the displacement and average velocity of the center of pressure (CoP) in the medial-lateral (ML) and anterior-posterior (AP) directions in 3 distinct sections during gait initiation, which correspond to the CoP position toward the swing limb, stance limb and progression line, respectively.Results: Individuals with stroke presented shorter and slower step, shorter and slower CoP-ML and CoP-AP toward swing limb and Cop-ML towards stance limb, and longer and faster CoP-AP toward stance limb compared to their peers. The BWS lead individuals with stroke to decrease step length and to increase CoP-ML displacement and average velocity toward stance limb.Conclusion: Individuals with stroke present impairments in executing gait initiation mainly during the preparation period and the employment of an overground BWS system promotes a better performance. These results suggest that BWS is a functional strategy that enables individuals with stroke to modulate gait initiation and it could be adopted for gait intervention. [ABSTRACT FROM AUTHOR]

The functional reach test (FRT) is widely used for assessing dynamic balance stability in elderly and pathological subjects. Force platforms (FPs) represent a fundamental part of the instrumented FRT experimental setup due to the central role of center-of-pressure (COP) displacement in FRT analysis. Recently, the nintendo wii balance board (NBB) has been suggested as a low-cost and reliable device for ground reaction force and COP measurement in poorly dynamic motor tasks. Therefore, this paper aimed to compare NBB-COP data with those obtained from a laboratory-grade platform during FRT. Data from 48 healthy subjects were simultaneously acquired from both devices. FP-COP and NBB-COP trajectories showed a remarkable correlation in both directions ( ${r}>\textsf {0.990}$ ) and low root-mean-square error values (1.14 ± 0.88 mm and 0.55 ± 0.28 mm for anterior–posterior and medial–lateral direction). Fixed biases between COP-based parameters did not exceed 2% of the FP outcomes with high consistency throughout the present measurement range (ICC consistency always >0.950). Only the COP mean velocity exhibited a tendency toward proportional errors, which can be adjusted by a calibration of NBB data. Findings of this paper confirmed the NBB validity for COP measurement in a widely used motor task as the functional reach, supporting the feasibility of NBB in research scenarios. [ABSTRACT FROM AUTHOR]

Balance is a complex, sensorimotor task requiring an individual to maintain the center of gravity within the base of support. Quantifying balance in a reliable and valid manner is essential to evaluating disease progression, aging complications, and injuries in clinical and research settings. Typically, researchers use force plates to track motion of the center of gravity during a variety of tasks. However, limiting factors such as cost, portability, and availability have hindered postural stability evaluation in these settings. This study compared the “gold standard” for assessing postural stability (i.e., the laboratory-grade force plate) to a more affordable and portable assessment tool (i.e., BTrackS balance plate) in healthy young adults. Correlations and Bland-Altman plots between the center of pressure outcome measures derived from these two instruments were produced. Based on the results of this study, the measures attained from the portable balance plate objectively quantified postural stability with high validity on both rigid and compliant surfaces, demonstrated by thirty-five out of thirty-eight observed postural stability metrics in both surface conditions with a correlation of 0.98 or greater. The low cost, portable system performed similarly to the lab-grade force plate indicating the potential for practitioners and researchers to use the BTrackS balance plate as an alternative to the more expensive force plate option for assessing postural stability, whether in the lab setting or in the field. [ABSTRACT FROM AUTHOR]

Testing balance through squatting exercise is a central part of many rehabilitation programs and sports and plays also an important role in clinical evaluation of residual motor ability. The assessment of center of pressure (CoP) displacement and its parametrization is commonly used to describe and analyze squat movement and the laboratory-grade force plates (FP) are the gold standard for measuring balance performances from a dynamic view-point. However, the Nintendo Wii Balance Board (NWBB) has been recently proposed as an inexpensive and easily available device for measuring ground reaction force and CoP displacement in standing balance tasks. Thus, this study aimed to compare the NWBB-CoP data with those obtained from a laboratory FP during a dynamic motor task, such as the squat task. CoP data of forty-eight subjects were acquired simultaneously from a NWBB and a FP and the analyses were performed over the descending squatting phase. Outcomes showed a very high correlation ( r ) and limited root-mean-square differences between CoP trajectories in anterior-posterior ( r  > 0.99, 1.63 ± 1.27 mm) and medial-lateral ( r  > 0.98, 1.01 ± 0.75 mm) direction. Spatial parameters computed from CoP displacement and ground reaction force peak presented fixed biases between NWBB and FP. Errors showed a high consistency (standard deviation < 2.4% of the FP outcomes) and a random spread distribution around the mean difference. Mean velocity is the only parameter which exhibited a tendency towards proportional values. Findings of this study suggested the NWBB as a valid device for the assessment and parametrization of CoP displacement during squatting movement. [ABSTRACT FROM AUTHOR]

The NintendoWii Balance Board (WBB) has been suggested as an inexpensive, portable and accessible alternative to costly laboratory-grade force plates for measuring the vertical ground reaction force (vGRF) and center of pressure (COP). Kinetic gait analysis provides important information for the rehabilitation of patients with gait disorders; however, the validity of the WBB for measuring kinetic gait parameters has not been evaluated. Therefore, the purpose of this study is to determine the accuracy of walking force measurements—which change dynamically in a short period of stance time—collected with the WBB. Three healthy adults were asked to walk 10 steps along both straight and curved paths in clockwise (CW) and counterclockwise (CCW) directions while measurements were taken using the WBB and the force plate. The accuracy of the vGRF, COP trajectory, and stance duration were evaluated using the root-mean-square error (RMSE), Pearson's correlation coefficient and Bland–Altman plots (BAPs) to compare the WBB and the force plate. The results of the vGRF showed high accuracy (r > 0.96 and %RMSE < 6.1% in the mean values), and the stance duration as defined by the vGRF and COP trajectory was equivalent to that of commercial instrumented insoles, which are used as an alternative to the force plates. From these results, we determined that the WBB may be used for kinetic gait analysis in clinical settings where lower accuracy is acceptable. [ABSTRACT FROM AUTHOR]

The measurement of the center of pressure (CoP) is one of the most frequently used quantitative methods for quantifying postural performance. Due to the complexity and the high biological variability of the postural control loop, a large number of different methods and parameters have been established to describe the CoP process. Furthermore, the methodological conditions such as the foot position, visual condition, sampling duration, and the data processing also have a relevant influence on the measurement results. In addition, there are various methods for recording the pressure curve, which differ in particular with regard to the filters used, the frequencies, and measurement times. The aim of the present study was the methodical comparison between different digital filters, measurement frequencies and times, and their effects on the CoP process based on a healthy reference group. The data acquisition was done with LabVIEW and the data storage was organized in a subject oriented data structure. Based on the presented results it could be seen that with a different dominant frequency in the spectrum of the group of test persons, certain filter types are required for the processing of CoP data. In the sampling range from 300 Hz to 1 kHz in the bipedal stand and 600 Hz to 1 kHz in the monopedal stand, the choice of measurement frequency had no influence on the filter result.

Objective: To provide normative postural stability data in young subjects.Methods: Ninety-six healthy participants (58W, 28±6y) stood on a force plate during 60s. We measured effects of support width (feet apart, FA; feet together, FT), vision (eyes open, EO; closed, EC), and cognitive load (single task, ST; dual tasking, DT) on anteroposterior (AP) and medio-lateral (ML) ranges, area and planar velocity of center of pressure (COP) trajectory.Results: All variables increased with FT (AP range, +15%; ML, +185%; area, +242%; velocity, +50%, p<0.0002 for all, MANOVA). Visual deprivation increased COP ranges with added constraints (FT or DT, p=0.002) and increased velocity in all conditions (FA/ST, +16%; DT, +18%; FT/ST, +29%; DT, +23%, p<0.0002 for all). Dual tasking reduced COP displacements with FT (AP range, EO, -15%; EC, -11%; ML range, EO, -19%; EC, -13%; area, EO, -40%; EC, -28%, p<0.0002 for all) and increased velocity in most conditions (FA/EO, +15%; FA/EC, +16%; FT/EO, +7%, p<0.0002 for all).Conclusion: In young healthy adults, base of support reduction increases COP displacements. Vision particularly affects postural stability with feet together or dual tasking. Dual tasking increases velocity but decreases COP displacements in challenging postural tasks, potentially by enhanced lower limb stiffness. [ABSTRACT FROM AUTHOR]

The center of pressure (CoP) is one of the most utilized quantitative measurements describing postural competency. Due to the complexity and biological variability of postural regulatory systems, a myriad of different methods and parameters have been established describing the CoP trajectory. Besides procedural variables, such as foot position, visual condition, and sampling duration, the method of data collection itself has a relevant effect on the result of the measurement. Furthermore, different methods for recording the measured data have been developed, which differ regarding the filters, frequencies, and test durations used. The goal of this study was the methodical comparison of various filters, measurement frequencies, and measurement duration, with respect to their effects on the CoP trajectory. Based on the results presented, we demonstrate that the Butterworth and Bessel filters can be recommended for analysis of CoP data, and at the very least, a second-order filter should be chosen for the process. For assessment of the cutoff frequency, a technical pendulum was used to show that a cutoff frequency of 13 Hz provided reliable data and it can be inferred that a 100 Hz sampling rate would be the minimum requirement.

The Nintendo Wii Balance Board (WBB) has been suggested as an inexpensive, portable and accessible alternative to costly laboratory-grade force plates for measuring the vertical ground reaction force (vGRF) and center of pressure (COP). Kinetic gait analysis provides important information for the rehabilitation of patients with gait disorders; however, the validity of the WBB for measuring kinetic gait parameters has not been evaluated. Therefore, the purpose of this study is to determine the accuracy of walking force measurements—which change dynamically in a short period of stance time—collected with the WBB. Three healthy adults were asked to walk 10 steps along both straight and curved paths in clockwise (CW) and counterclockwise (CCW) directions while measurements were taken using the WBB and the force plate. The accuracy of the vGRF, COP trajectory, and stance duration were evaluated using the root-mean-square error (RMSE), Pearson’s correlation coefficient and Bland–Altman plots (BAPs) to compare the WBB and the force plate. The results of the vGRF showed high accuracy (r > 0.96 and %RMSE < 6.1% in the mean values), and the stance duration as defined by the vGRF and COP trajectory was equivalent to that of commercial instrumented insoles, which are used as an alternative to the force plates. From these results, we determined that the WBB may be used for kinetic gait analysis in clinical settings where lower accuracy is acceptable.

Traditional biomechanical analyses have focused primarily on the human gait across hard, flat surfaces and provide little information about human locomotion as a function of work environment or terrain. The purpose of this study was evaluation of a force plate system for measure of center of pressure (COP) in railroad ballast by comparing its accuracy across three surface conditions (hard surface, mainline ballast and walking ballast) with two configurations (level and 7° cross-slope). Custom walkways and an isolation fixture were developed to rigidly attach a force plate beneath ballast surfaces to collect the COP. The difference in COP location (ΔCOPx, y, z) between the force plate system and a calibration system (motion capture derived) were compared using repeated-measures analysis of variance. Results indicate that the effects of surface condition and configuration were not significant for ΔCOPx, y, z and no differences were found among the three surface conditions during pairwise comparison, though ΔCOPx, y, z were different between the center and corners of the force plate in ballasts for both level and cross-slope configurations. The system presented in this study demonstrates the feasibility of measuring the COP by using an isolation-fixture force plate to expand the scope of biomechanical studies on ballast surfaces that are level or cross-slope. [ABSTRACT FROM AUTHOR]

Introduction: Falls are one of the major problems among the elderly population. It has been established that people with dementia fall down more often. It is believed that this is a consequence of risky decision making by people with dementia resulting from cognitive deterioration. The aim of the present study was to evaluate the relationship between cognitive status and postural stability while standing. Methods: A total of 47 people, aged 71.6 years on average (±7.2), were divided based on results of the Mini Mental State Examination (MMSE) into a dementia group (MMSE ≤ 23) and a control group (MMSE > 23). Postural stability was tested using a force plate (with eyes open, with eyes closed, and with visual biofeedback). The parameters of movement of the center of pressure were analyzed. Results: Both in test with eyes open and eyes closed, significant difference was shown between the dementia group and the control groups. In visual feedback test, the dementia group showed 32% poorer performance than the controls. Conclusion: The falls experienced in dementia group may be caused by a disturbed balance control process of the central nervous system. [ABSTRACT FROM AUTHOR]

Force plates are frequently used to collect the ground reaction forces (GRF) and center of pressure (COP) during gait. The calculated COP is affected by the material type and thickness covering the top surface. If the surface is deformable, these effects can be significant. The purpose of this study is to simulate and evaluate the effects of deformation height when calculating the COP in a deformable surface during gait. The GRF and COP data during normal gait were collected from 20 healthy adult males on sand in two conditions (level and cross-slope of 10°). The COP differences in the anteroposterior (AP) and mediolateral (ML) directions were modeled for constant deformation heights (10–50 mm, 10 mm increments). The results showed the magnitude of COP changes in the AP and ML directions were different in both level and cross-slope conditions. A significantly larger COP ML difference was shown for the cross-slope condition than level condition for the same deformation height. The COP was more sensitive to the deformation height for the downhill limb than uphill limb in the cross-slope condition. The results of this study suggest that the maximum allowable deformation height before a correction for surface deformation is needed is 20 mm for level condition and 10 mm for cross-slope condition, where 3 mm difference in COP is considered as the tolerance limit. Surface deformations beyond these thresholds may lead to an inaccurate interpretation and evaluation of joint kinetics during gait on deformable surfaces. [ABSTRACT FROM AUTHOR]

Background and Aim: The calculated parameters of the center of pressure (COP) are suitable indicators for evaluating balance in patients after rehabilitation. Therefore, determining the reliability level of each parameter is a matter of great importance. This study tried to determine the reliability of some parameters of the COP sway in patients with myofascial neck pain in different postural situations. Materials and Methods: The present study is a test-retest reliability design. Twenty patients with myofascial neck pain performed a single and a double leg test with open and closed eyes on a force plate and with open eyes on foam in three sessions with a 30 minute intervals for 30 seconds. Antero-posterior and medio-lateral sway range, mean velocity and mean area of sway were calculated. Results: The mean velocity showed high reliability (0.98) in all situations, but the other parameters were variable in different situations. Conclusions: The results showed that some COP parameters are highly reliable in assessment of patients with myofascial neck pain. [ABSTRACT FROM AUTHOR]

Archery is described as a static sport requiring fine movement control. proper endurance and strength of the upper body and balance ability. The purpose of this study was to identify the effect of the sway of centre of pressure (COP) with eyes open (EO), eyes closed (EC), dominant and non-dominant eyes open during quiet stance in three Archery disciplines. Fifteen archers (Group I: The Recurve Archery (RA): n=5, Group II: Compound Archery (CA): n=5, Group III: Traditional Archery (TA): n=5) participated voluntary in the study. An 9281EA BioKistler Force Plate system was used to obtain objective measurements of balance in mediolateral (Ay) and anterio-posterior (Ax) directions of the sway of COP during the trials. As a result, sway of COP of CA group was smaller than the RA and TA group. Compound archers have better static balance ability than the other groups during quiet stance. Therefore, different archery disciplines, equipment, muscular strategies and skill have some effect on postural control performance measurements. [ABSTRACT FROM AUTHOR]

Training and testing of balance have potential applications in sports and medicine. Laboratory grade force plates (FP) are considered the gold standard for the measurement of balance performance. Measurements in these systems are based on the parameterization of center of pressure (CoP) trajectories. Previous research validated the inexpensive, widely available and portable Nintendo Wii Balance Board (WBB). The novelty of the present study is that FP and WBB are compared on CoP data that was collected simultaneously, by placing the WBB on the FP. Fourteen healthy participants performed ten sequences of single-leg stance tasks with eyes open (EO), eyes closed (EC) and after a sideways hop (HOP). Within trial comparison of the two systems showed small root-mean-square differences for the CoP trajectories in the x and y direction during the three tasks (mean ± SD; EO: 0.33 ± 0.10 and 0.31 ± 0.16 mm; EC: 0.58 ± 0.17 and 0.63 ± 0.19 mm; HOP: 0.74 ± 0.34 and 0.74 ± 0.27 mm, respectively). Additionally, during all 420 trials, comparison of FP and WBB revealed very high Pearson's correlation coefficients (r) of the CoP trajectories (x: 0.999 ± 0.002; y: 0.998 ± 0.003). A general overestimation was found on the WBB compared to the FP for 'CoP path velocity' (EO: 5.3 ± 1.9%; EC: 4.0 ± 1.4%; HOP: 4.6 ± 1.6%) and 'mean absolute CoP sway' (EO: 3.5 ± 0.7%; EC: 3.7 ± 0.5%; HOP: 3.6 ± 1.0%). This overestimation was highly consistent over the 140 trials per task (r > 0.996). The present findings demonstrate that WBB is sufficiently accurate in quantifying CoP trajectory, and overall amplitude and velocity during single-leg stance balance tasks. [ABSTRACT FROM AUTHOR]

Abstract: Background: In-shoe center of pressure (COP) measurement is essential in biomechanics. COP can be measured directly utilizing pressure-sensitive insoles, or calculated indirectly via force plate-generated data. While the latter does not require the use of additional measurement hardware (shoe insoles), its precision at calculating in-shoe COP has not been determined. Our purpose was to ascertain the precision of force plate in-shoe COP calculations and enhance their accuracy through a mathematical algorithm. Methods: Twelve male students participated in the study. In-shoe COP was measured synchronously via the Pedar-X insole system and AMTI force plates, comparing the measurements of both systems. A mathematical algorithm was created to improve agreement between the systems and comparisons were recalculated. Results: The two methods showed different measurements of in-shoe COP. The medio-lateral (ML) and anterior-posterior (AP) Pearson correlation coefficients between systems were 0.44±0.35 and 0.99±0.01, and the ML and AP RMS errors were 6.3±3.0mm and 43.0±12.5mm, respectively. Using a mathematical algorithm, the differences between the measurements of each system could be reduced significantly (all P <0.001). Conclusions: Without adjustment, force plates give an approximate location of the COP. Using an adjustment model greatly improves the accuracy of the COP trajectory during stance. [Copyright &y& Elsevier]