Center Of Pressure Characteristics Research Articles

Load Carriage and Changes in Spatiotemporal and Kinetic Biomechanical Foot Parameters during Quiet Stance in a Large Sample of Police Recruits

Background: Little evidence has been provided regarding the effects of carrying standardized load equipment and foot parameters during quiet standing. Therefore, the main purpose of the study was to examine whether a load carriage might impact static foot parameters in police recruits. Methods: Eight hundred and forty-five police recruits (27.9% women) were tested in ‘no load’ vs. standardized ‘3.5 kg load’ conditions. Foot characteristics during standing were assessed with the Zebris FDM pedobarographic pressure platform. Results: Carrying a 3.5 kg load significantly increased the 95% confidence ellipse area (∆ = 15.0%, p = 0.009), the center of pressure path length (∆ = 3.3%, p = 0.023) and average velocity (∆ = 11.1%, p = 0.014), the length of the minor axis (∆ = 8.2%, p < 0.009) and the deviation in the X (∆ = 12.4%, p = 0.005) and Y (∆ = 50.0%, p < 0.001) axes. For relative ground reaction forces, a significant increase in the left forefoot (∆ = 2.0%, p = 0.002) and a decrease in the left hindfoot (∆ = −2.0%, p = 0.002) were shown. No significant changes in relative ground reaction forces beneath the forefoot and hindfoot regions for the right foot were observed (p > 0.05). Conclusions: The findings suggest that spatial and temporal foot parameters may be more prone to change while carrying heavy loads, especially the center of pressure characteristics.

Impact of carrying heavy loads on postural sway and relative ground reaction forces during quiet stance in intervention police officers

Although carrying heavy loads impacts gait characteristics in military personnel, less studies have examined whether a gradually load increase affects foot parameters during quiet standing in the different population of intervention police officers. Therefore, the main purpose of the study was to examine differences in postural sway and ground reaction force characteristics during a quiet stance while carrying progressively heavier equipment. Ninety-six elite intervention male police officers were assessed under four conditions: (i) ‘no load’, (ii) ‘a 5 kg load’, (iii) ‘a 25 kg load’, and (iv) ‘a 45 kg load’. Foot characteristics during standing were assessed with the Zebris pedobarographic pressure platform. Heavier loads increased 95% confidence ellipse area (p=.012, η2=0.028), the center of pressure path length (p=.010, η2=0.029) and average velocity (p=.011, η2=0.029), and length of the minor (p<.001, η2=0.040) and major axis (p=.004, η2=0.035). No significant changes in relative ground reaction forces beneath the forefoot and hindfoot regions of both feet were observed (p>.05). The findings suggest that spatial and temporal foot parameters may be more prone to change while carrying heavy loads, especially the center of pressure characteristics.

Stepping into emotions: investigating the effect of angry and fearful faces on forward stepping and quiet stance.

Facial expressions conveying an emotion may affect social interactions, such as approach- or avoidance-related behaviors. A specific facial feature is the gaze direction. An emotional facial expression such as anger will elicit distinct behavioral tendencies, depending on whether the angry gaze is directed toward the onlooker, or in a different direction. We tested whether facial expressions of anger and fear, combined with direct or averted gaze, elicit approach- or avoidance tendencies, using a go/no-go variant of the whole-body stepping task. Healthy adults stood on a force plate, recording the center of pressure (COP). Participants were presented with angry or fearful faces; either with direct or averted gaze. Participants had to identify the emotion, and "depending on instructions- either make a single step forward, or remain in a quiet stance. From the COP of the forward steps, we derived parameters such as reaction time and step size. From the quiet standing trials we derived parameters of postural sway, indicative of postural "freeze." We used analysis of variance to analyze the outcomes. First, we found that steps were initiated faster with angry faces than with fearful faces, in line with existing literature. Second, we did not observe a significant effect of gaze direction. Forward steps with direct and averted gaze had similar COP characteristics. Finally, we had expected to find freeze (postural immobility) with fearful faces, but this was also not observed. We discuss various explanations for the finding, and implications for research into the motoric grounding of social interactions.

Center of pressure characteristics differ during single leg stance throughout pregnancy and compared to nulligravida individuals

BackgroundFalls are common during pregnancy and present potential for injury to the pregnant individual and the baby. Research questionDo center of pressure characteristics during single leg stance differ between participants during and after pregnancy and nulligravida participants in the presence and absence of visual input? MethodsNineteen pregnant participants completed testing during the second trimester, the third trimester, and 4–6 months post-partum. Matched, nulligravida females completed testing once. All participants performed single leg stance on a force platform on each limb for up to 20 s with eyes open and with eyes closed. Center of pressure characteristics were compared between pregnant and nulligravida females using three separate 2 × 2 mixed way ANOVAs, one for each pregnancy time point (second trimester, third trimester, and post-partum) with Bonferroni correction. ResultsPregnant females demonstrated smaller single leg stance time with eyes closed during the third trimester. During the second and third trimester, pregnant participants demonstrated smaller sway and sway velocity across eyes open and eyes closed conditions. During the third trimester and post-partum, pregnant participants demonstrated greater median frequency of the center of pressure data. Pregnant participants also demonstrated smaller sample entropy in the anteroposterior direction during the second and third trimesters and in the mediolateral direction during the second trimester. SignificanceThe decreased total sway and sway velocity observed during pregnancy may reflect rigidity or a protective strategy during single limb stance. Additionally, center of pressure data were less smooth and more repetitive during pregnancy indicating robust differences in postural control strategies and potentially increased fall risk. Because single limb stance is a component of many activities of daily living, the single limb stance task may have clinical utility for testing or training balance in this population with a goal of decreasing falls.

Does weight loss affect the center of pressure of children with obesity: a follow-up study

BackgroundChildren with obesity were found to show the greater postural instability compared to the normal-weighted children. However, it’s still unclear if their altered postural control ability would recover towards normal pattern after weight loss. The purpose of this study was to investigate the effect of weight loss on the center of pressure (COP) for obese children.MethodTotally 147 children were conducted a follow-up study in three years. A total number of 22 participants aged 7–13 years were recruited for their remission of obesity problem after 36 months. Their dynamic plantar pressure data were collected by Footscan pressure plate. The normalized time of four sub-phases, displacements and velocities of COP in anterior–posterior (AP) and medial–lateral (ML) directions were calculated to perform the Kolmogorov–Smirnov test and paired sample t test for statistical analyses.ResultsAfter weight loss, children’s normalized time of forefoot contact phase (FFCP) increased significantly, and their duration of flat foot phase (FFP) decreased significantly. They also exhibited the more medial and posterior orientated COP path after weight loss. In ML-direction, the COP displacement during FFP and FFPOP increased, and the COP velocity during FFPOP increased. In AP-direction, COP velocity during FFP and FFPOP increased.ConclusionsThe findings indicated that weight loss would have effects on the COP characteristics and postural stability for obese children. COP trajectory can provide essential information for evaluating foot function. The findings may be useful for obese children, medical staff, and healthcare physician.Graphical

Acquiring Expertise in Precision Sport – What Can We Learn from an Elite Snooker Player?

Snooker can be an attractive life-long physical activity, given its popularity across all age groups in Asia and Europe. However, scientific research on the cueing movement is limited. This case study presented the biomechanical profiles of the cueing movement in an elite male snooker player (age 37 years old, height 173 cm, body mass 70 kg). Kinematics of the upper limb and cue stick, were examined in five selected snooker tasks (warm-up, stun, top spin, back spin, and stop shots) using the Vicon motion capture system. Ground reaction forces and centre of pressure characteristics were recorded using two Kistler force platforms. Results showed that the cueing movement was contributed primarily by elbow flexion/extension and much less wrist flexion/extension. The high degree of cue stick position overlap between the practice swing and final stroke indicated high level of cueing precision. Weight transfer between feet revealed a slight lean towards the left foot throughout the final stroke, confirming that the elite player was able to maintain high stance stability when executing the cueing movement. Results presented in the present study can serve as a reference for practitioners and scientists to detect error, enhance training, and improve performance in snooker. For practical applications, snooker players are advised to stabilise their shoulder during the cueing movement and deliver the cue stick primarily via elbow movements.

A Wireless Sensorized Insole Design for Spatio-Temporal Gait Analysis

Gait disorders significantly affect the quality of life and limit individual freedom of the subjects affected. Our knowledge of the spatio-temporal gait parameters provides great insight into the musculoskeletal biology, especially into the foot pathology during gait. The aim of our study was to develop a wireless insole system for both feet and to quantify the gait parameters along with the center of pressure (CP) trajectory. Force-sensitive resistors (FSRs) were used as the pressure sensing elements for experimental study on a total of 10 healthy subjects (28 ± 2.7 years). The subjects were asked to walk with the instrumented insoles on three different terrain lengths of 12, 16, or 20 m. The gait parameters (number of strides, stride length, % swing, % stance, etc.), and the CP trajectory for each step of both feet was calculated. It was statistically established that the stance percentage of each foot is generally greater, on average, than the swing percentage. Continuous evaluation of the foot trajectory revealed new insights into the intratrial characteristics of the subjects. The reproducibility of the device has been tested by repeating the experiment for three trials for each path length, and the results demonstrated that the gait parameters, including CP positions, are consistent with each other. An indigenous device has been developed to quantify various gait parameters. The CP trajectories were compared for each trial of a subject, and the results led to the conclusion that the gait of a subject remains constant, irrespectively of the number of trials and path distance. The parameters and CP characteristics provide beneficial knowledge of the appropriate gait performance evaluation and foot functions for clinical rehabilitation.

Center of pressure characteristics from quiet standing measures to predict the risk of falling in older adults: a protocol for a systematic review and meta-analysis

BackgroundFalling is the most common accident of daily living and the second most prevalent cause of accidental death in the world. The complex nature of risk factors associated with falling makes those at risk amongst the elderly population difficult to identify. Commonly used clinical tests have limitations when it comes to reliably detecting the risk of falling, but existing laboratory tests, such as force platform measurements, represent one method of overcoming this lack of a test. Despite their widespread use, however, Center of Pressure (COP) signal analysis techniques vary and there is currently no consensus on which features should be used diagnostically. Our objective is to identify, through a systematic review and meta-analysis, the COP characteristics of older adults (≥ 60 years old) during quiet bipedal stance which will allow fallers to be distinguished from non-fallers.MethodsThe systematic review will include both prospective and retrospective articles. Five databases will be searched: PubMed, Cochrane CENTRAL, EMBASE, and ScienceDirect. In addition, a search of gray literature will be performed using Google Scholar and ClinicalTrials.gov. Searches will be circumscribed to include only older adults (aged over 60 years) who underwent a bipedal quiet standing measure of their balance and for whom the number of falls was reported. Two authors will independently assess the risk of bias for each included article using a 26-item checklist. Funnel plots will be drawn to attest of possible publication biases for each COP parameters. The results will be synthesized descriptively and a meta-analysis will be undertaken. When trial methodological heterogeneity is too great for pooling of the data into a meta-analysis, evidence strength will be evaluated using best evidence analysis.DiscussionDespite the numerous advantages of posturography, the diversity of studies exploring balance in older fallers has led to uncertainty regarding the method’s ability to reliably identify fall-prone older adults. It is expected that the findings from this systematic review will help clinicians use bipedal quiet standing measures as a diagnostic test and allow researchers to explore COP characteristics to create better models for fall prevention care.Systematic review registrationPROSPERO CRD42018098671

Center of pressure limb path differences for the detection of lameness in dogs: a preliminary study

BackgroundThe limb center of pressure (COP) path measures and quantifies the load distribution within a limb in a still or moving subject. Under this premise, the aim of this study was to test whether data derived from this parameter could detect the differences between sound and lame limbs in unilaterally lame dogs with elbow dysplasia.To accomplish this purpose, ten unilaterally lame dogs of similar conformation were walked over a pressure platform. Next, the COP path, in relation to the position of sound and lame limbs, was measured in a coordinate system over a standard paw template obtained by pedobarography during the whole support phase. To compare variables, force platform data (peak vertical force and vertical impulse) from the same animals were obtained. Sound and lame limb statokinesiograms were also obtained while the animals stood still.ResultsThe statistical analysis clearly showed that COP in lame limbs start cranially and were shorter than sound limbs. In addition, the value of the COP excursion index was lower in lame limbs. Finally, the area of statokinesiograms was greater in lame limbs.ConclusionThis methodology based in limb COP characteristics serves to discriminate between sound and lame limbs in dogs with elbow dysplasia.

ANTERIOR CRUCIATE LIGAMENT SECTIONING ALTERS CENTER OF PRESSURE WITHIN THE TIBIOFEMORAL JOINT: AN IN VITRO STUDY

Anterior cruciate ligament (ACL) injuries often lead to secondary injuries, joint degradation, and were linked to osteoarthritis. There is little known about how ACL rupture affects the loading and contact characteristics within the tibiofemoral joint. The objective of this study was to evaluate changes in tibiofemoral joint contact pressure and center of pressure (COP) during dynamic motion before and after ACL sectioning in vitro. Six intact cadaveric knees were manipulated through three full cycles of motion ranging from 30∘ to 120∘ of flexion in a custom-built device. A pressure sensor inserted in the tibiofemoral joint measured contact pressure of the medial and lateral compartments as well as COP characteristics of the whole joint before and after the ACL was sectioned. There was a significant decrease in lateral-compartment peak pressure, medial and lateral mean pressure, and total contact area after the ACL was sectioned. In both intact and ACL deficient knees, a posterior-lateral shift in COP was observed during flexion and a medial-anterior shift when returning to extension. Plotting the COP trajectory through the flexion-extension cycle resulted in a distinct hysteresis curve due to the viscoelastic soft tissue properties. Following sectioning, the COP trajectory had a diminished area compared to the intact condition. The diminished area of contact pressure may be more problematic than the overall magnitude when the integrity of the ACL is compromised. The centralized pressure distribution to a smaller surface area over time may cause focal damage to the cartilage leading to osteoarthritis.

Постуральные ответы на движущиеся звуковые образы в зависимости от ведущей сенсорной модальности при ориентации в пространстве

Influences of individual characteristics of sensory information processing in humans on postural responses to approaching and receding sound images were investigated. Two groups of subjects with different cognitive style were examined (8 field-dependent and 9 field-independent individuals). Stabilographic signals before, during and after sound stimulation of different types (approaching, receding and unmoving sound images) were recorded, and the following characteristics of the center of pressure (COP) sway along sagittal axis were analyzed: COP trajectory length, average linear velocity, COP shift, and variation. Substantial differences were revealed between the strategies of equilibrium maintenance in the two groups of subjects. COP variation was higher for the field-independent group of subjects in all time intervals. Comparative analysis of COP characteristics received during sound stimulation showed that COP trajectory length and average linear velocity in the field-independent group was higher than ones in the field-dependent group only for receding sound images. Field-dependent subjects demonstrated reliable backward COP shift during listening by subject to approaching sound images. Unmoving sound images received during their listening did not influence any of the studied COP characteristics. The differences in postural control system responses, which were revealed, are in good agreement with the idea about predominant usage of sensory information of different modalities by the investigated groups of subjects: exteroceptive information in field-dependent, and proprioceptive in field-independent individuals.

Centre of pressure characteristics during walking in individuals with and without first metatarsophalangeal joint osteoarthritis

ObjectiveThe objective of this study was to compare centre of pressure characteristics during walking in individuals with and without first metatarsophalangeal joint osteoarthritis (1st MTPJ OA), in order to provide insights into alterations in foot function associated with this condition. MethodsTwenty people with 1st MTPJ OA and 20 asymptomatic controls matched for age, sex and body mass index underwent gait analysis using the emed®-x400 plantar pressure system (Novel GmbH, Germany). Average and maximum centre of pressure velocity and lateral-medial force index during loading, midstance, terminal stance and preswing were compared between the groups. ResultsDuring the preswing phase of gait, maximum centre of pressure velocity was significantly slower in individuals with 1st MTPJ OA (0.78 ± 0.19 vs 1.13 ± 0.36 m/sec; p = 0.003), and both average and maximum lateral-medial force indices were significantly higher in individuals with 1st MTPJ OA (0.98 ± 0.14 vs 0.82 ± 0.13; p < 0.001 and 1.37 ± 0.29 vs 1.15 ± 0.15; p = 0.008, respectively). Non-weightbearing 1st MTPJ dorsiflexion range of motion was significantly associated with maximum centre of pressure velocity (r = 0.54, p < 0.001) and average lateral-medial force index (r = −0.44, p = 0.004) during preswing. ConclusionsIndividuals with 1st MTPJ OA exhibit significant differences in centre of pressure characteristics during propulsion, possibly due to decreased range of available 1st MTPJ dorsiflexion.

Centre of pressure characteristics in normal, planus and cavus feet

BackgroundThe aim of this study was to compare centre of pressure (COP) characteristics between healthy adults with normal, planus or cavus feet who were allocated to groups based on reliable foot posture measurement techniques.MethodsNinety-two healthy adult participants (aged 18 to 45) were recruited and classified as either normal (n = 35), pes planus (n = 31) or pes cavus (n = 26) based on Foot Posture Index, Arch Index and normalised navicular height truncated measurements. Barefoot walking trials were conducted using an emed®-x 400 plantar pressure system (Novel GmbH, Munich, Germany). Average, maximum, minimum and range (difference between maximum and minimum) values were calculated for COP velocity and lateral-medial force index during loading response, midstance, terminal stance and pre-swing phases of stance. The COP excursion index was also calculated. One-way analyses of variance were used to compare the three foot posture groups.ResultsThe cavus foot exhibited the slowest average and minimum COP velocity during terminal stance, but this pattern was reversed during pre-swing, when the cavus foot exhibited the fastest maximum COP velocity. The planus foot exhibited the smallest lateral medial force index range during terminal stance. There were no differences between the groups for COP excursion index.ConclusionThese findings indicate that there are differences in COP characteristics between foot postures, which may represent different mechanisms for generating force to facilitate forward progression of the body during the propulsive phases of gait.

Sample Entropy, Univariate, and Multivariate Multi-Scale Entropy in Comparison with Classical Postural Sway Parameters in Young Healthy Adults.

The present study aimed to compare various entropy measures to assess the dynamics and complexity of center of pressure (COP) displacements. Perturbing balance tests are often used in healthy subjects to imitate either pathological conditions or to test the sensitivity of postural analysis techniques. Eleven healthy adult subjects were asked to stand in normal stance in three experimental conditions while the visuo-kinesthetic input was altered. COP displacement was recorded using a force plate. Three entropy measures [Sample Entropy (SE), Multi-Scale Entropy (MSE), and Multivariate Multi Scale Entropy (MMSE)] describing COP regularity at different scales were compared to traditional measures of COP variability. The analyses of the COP trajectories revealed that suppression of vision produced minor changes in COP displacement and in the COP characteristics. The comparison with the reference analysis showed that the entropy measures analysis techniques are more sensitive in the incremented time series compared to the classical parameters and entropy measures of original time series. Non-linear methods appear to be an additional valuable tool for analysis of the dynamics of posture especially when applied on incremental time series.

Unilateral Hearing Loss Is Associated With Impaired Balance in Children: A Pilot Study.

To determine if children with unilateral sensorineural hearing loss (UHL) demonstrate impaired balance compared with their normal hearing (NH) peers. Prospective, case-control study. Balance was assessed in14 UHL and 14 NH children using the Bruininks-Oseretsky Test-2 (BOT-2) and time to fall (TTF) in an immersive, virtual-reality laboratory. Postural control was quantified by center of pressure (COP) using force plates. The effect of vision on balance was assessed by comparing scores and COP characteristics on BOT-2 tasks performed with eyes open and closed. Balance ability as measured by the BOT-2 score was significantly worse in children with UHL compared with NH children (p = 0.004). TTF was shorter in children with UHL compared with NH children in the most difficult tasks when visual and somatosensory inputs were limited (p < 0.01). Visual input improved postural control (reduced COP variability) in both groups in all tasks (p < 0.05) but postural control as measured by COP variability was more affected in children with UHL when visual input was removed while performing moderately difficult tasks (i.e., standing on one foot) (p = 0.02). In this pilot study, children with UHL show poorer balance skills than NH children. Significant differences in TTF between the two groups were only seen in the most difficult tasks and therefore may be missed on routine clinical assessment. Children with UHL appear to rely more on vision for maintaining postural control than their NH peers. These findings may point to deficits not only in the hearing but also the vestibular portion of the inner ear.

Balance failure in single limb stance due to ankle sprain injury: An analysis of center of pressure using the fractal dimension method

Instrumented postural control analysis plays an important role in evaluating the effects of injury on dynamic stability during balance tasks, and is often conveyed with measures based on the displacement of the center-of-pressure (COP) assessed with a force platform. However, the desired outcome of the task is frequently characterized by a loss of dynamic stability, secondary to injury. Typically, these failed trials are discarded during research investigations, with the potential loss of informative data pertaining to task success. The novelty of the present study is that COP characteristics of failed trials in injured participants are compared to successful trial data in another injured group, and a control group of participants, using the fractal dimension (FD) method. Three groups of participants attempted a task of eyes closed single limb stance (SLS): twenty-nine participants with acute ankle sprain successfully completed the task on their non-injured limb (successful injury group); twenty eight participants with acute ankle sprain failed their attempt on their injured limb (failed injury group); sixteen participants with no current injury successfully completed the task on their non-dominant limb (successful non-injured group). Between trial analyses of these groups revealed significant differences in COP trajectory FD (successful injury group: 1.58±0.06; failed injury group: 1.54±0.07; successful non-injured group: 1.64±0.06) with a large effect size (0.27). These findings demonstrate that successful eyes-closed SLS is characterized by a larger FD of the COP path when compared to failed trials, and that injury causes a decrease in COP path FD.

BALANCE FAILURE IN SINGLE LIMB STANCE DUE TO ANKLE SPRAIN INJURY: AN ANALYSIS OF CENTRE OF PRESSURE USING THE FRACTAL DIMENSION METHOD

BackgroundDynamic stability is ubiquitous to fulfilling daily living activities. Instrumented postural control analysis plays an important role in evaluating the effects of injury on dynamic stability during balance tasks, and...

Gait speed and gender effects on center of pressure progression during normal walking

The COP progression is the trajectory of the center of foot pressure. Thirty healthy young adults were recruited to participate in this study. All subjects were asked to walk randomly at four different speeds (3km/h, preferred walking speed, 4km/h and 5km/h). A foot pressure measurement system (RS-scan® system) was used to collect the center of pressure (COP) coordinates, COP progression angle and the COP velocity. Four sub-phases of the stance phase were calculated. The initial contact (ICP) and forefoot contact phase (FFCP) corresponded to the loading response. The foot flat phase (FFP) coincided with the mid-stance. The forefoot push-off phase (FFPOP) corresponded to the terminal stance and pre-swing phases. The results of this study indicate that the percentage of time (% time) of COP progression on the ICP, FFCP, FFP and FFPOP were approximately 7.0%, 4.8%, 48.8% and 39.4%, respectively. The COP progression angle was 4.1 (SD=1.6)° with an inward curve and the average COP velocity was 31.6cm/s (SD=5.3). The walking speed influenced the % time in the FFP and FFPOP. As the walking speed increased, the % time of COP progression decreased in mid-stance and increased in the terminal and pre-swing stances. Moreover, gender affected the COP progression angle. Men had a significantly larger deviating angle than women during FFCP, FFP and FFPOP. The COP characteristics can offer useful information for clinical rehabilitation in foot functional and structural evaluation.

EFFECTS OF AGE AND STEP DIRECTION ON BEHAVIORAL PERFORMANCES AND CENTER-OF-PRESSURE CHARACTERISTICS OF VOLITIONAL STEPPING IN OLDER AND YOUNG ADULTS

This study investigated center-of-pressure (COP) characteristics during volitional stepping in forward, backward, and sideways directions, along with the behavioral performance measures and COP measures of volitional stepping in these directions, and the relationships between these two types of measures in healthy older and young adults. Fifteen older and 15 young adults performed rapid stepping in the three directions using each leg. Behavioral performance measures included reaction time (RT), movement time (MT), step length, and step velocity in the MT phase. COP measures included the maximum anteroposterior (COPAP) and mediolateral COP displacement (COPML) in the RT phase. Stepping in each direction demonstrated unique COP characteristics. The older adults presented slower RT, MT, step velocity, and smaller COPAP in all three stepping directions (p &lt; 0.05), as well as smaller COPML in the sideways stepping direction (p &lt; 0.017), compared to the young adults. Step velocity correlated with COPAP and/or COPML in all three stepping directions for both groups (r = 0.42–0.77, p &lt; 0.05), suggesting that stepping performances during the movement execution phase correlated with COP control during the postural preparation phase. Results suggest that stepping training prescribed to older adults to improve their balance control may include multi-directional stepping.

Preliminary study of regionalised centre‐of‐pressure analysis in patients with juvenile idiopathic arthritis

Background Patients with Juvenile idiopathic arthritis (JIA) may exhibit altered plantar pressure distributions as a result of foot pain and/or deformities [1,2]. Previous work involving adult patients with rheumatoid arthritis suggests that altered loading patterns can be characterised by delayed transfer of the centre-of-pressure to the forefoot [3]. The aim of this study was to compare centre-ofpressure characteristics in pre-defined areas of the foot between patients with JIA and children without JIA.