Center Of Pressure Distance Research Articles

Heated environment increases blood pressure drop and postural sway during initial orthostasis in healthy subjects.

We tested the hypothesis that heat stress influences the closed-loop cardio-postural control by an increased blood pressure (BP) drop and postural sway. Fourteen healthy individuals (eight women) performed two orthostatic tests under thermal reference (TC; ~ 24ºC) and HOT (~ 38ºC) conditions. The center-of-pressure (COP) displacements and the electromyography (EMG) activity of the calf muscles (medial gastrocnemius and tibialis anterior) were recorded during the initial orthostasis (ORT onset) after the supine-to-stand challenge. At the same period, BP (beat-to-beat) was continuously monitored, and supine-to-stand variations (∆%) were calculated. Sublingual temperature (Tsl) was measured as a surrogate of internal temperature. Tsl increased in HOT compared to TC (TC 36.5 ± 0.3 vs. HOT 36.7 ± 0.3ºC; p < 0.01). COP distance was greater in HOT compared to TC condition (TC 596.6 ± 242.4 vs. HOT 680.2 ± 249.1mm; p < 0.01). EMG activity of the gastrocnemius decreased in HOT compared to TC condition (TC 95.5 ± 19.8 vs. HOT 78.4 ± 22.8%mV; p = 0.02). EMG of tibialis did not change between TC and HOT (TC 83.5 ± 42.9 vs. HOT 66.1 ± 31.9%mV; p = 0.29). BP showed a greater fall in HOT compared to TC condition (∆%TC -24.5 ± 13.2 vs. ∆%HOT -33.2 ± 20.2%; p = 0.01). Heat stress causes a greater fall in blood pressure and a reduction in musculoskeletal pump activity during orthostatic onset. These effects could be potential mechanisms that underlie augmented postural instability under a heated environment.

Effect of dynamic neuromuscular stabilization training using the inertial load of water on functional movement and postural sway in middle-aged women: a randomized controlled trial

BackgroundChronic stress and diseases occur more frequently in middle-aged compared to younger women and this is often the result of physical, psychological and socio-economic changes. These health consequences reduce lower body muscle mass and flexibility, leading to generalized impairments in functional movement and balance. Dynamic Neuromuscular Stabilization (DNS) training using the inertial load of water is known for its positive impact on functional strength improvement and muscle stabilization.ObjectiveThis study aimed to determine the effect of DNS training using inertial water loads on functional movement and postural sway in middle-aged women.MethodA sample of 24 middle-aged women participated in the study and were randomly divided into two groups: the experimental group, n = 12 (age: 58.33 ± 1.48 yrs, height: 162.16 ± 1.27 cm, weight: 61.77 ± 2.21 kg) and control group, n = 12 (age: 59.58 ± 1.13 yrs, height: 160.1 ± 1.13 cm, weight: 57.51 ± 1.12 kg). Center of Pressure (COP), moving distance, Root Mean Square (RMS), movement area and Functional Movement Screen (FMS) were conducted and analyzed pre- and post-examination. Participants engaged in the DNS training regimen, which utilized the inertial load of water, for 60 min each session, conducted twice weekly for 12 weeks.ResultsThere were significant differences in the COP distance (p < 0.001), RMS (p < 0.05), COP area and FMS test (p < 0.001) in the pre-post comparison of each group. And significant differences were found in COP distance (p < 0.05), RMS (p < 0.05), COP area (p < 0.05) and FMS test (p < 0.05) between groups. The DNS training improved the dynamic stability of single-leg standing, torso stability and functional movement in middle-aged women.ConclusionDNS training programs using the inertial load of water have been shown to be effective in movement improvement and posture retention ability, which is beneficial for functional movement, equilibrium strategy, and dynamic stability of middle-aged women. Furthermore, the DNS training method designed in this study can be useful for trainees who require posture correction in a safe and effective way regardless of their age and gender.

The Effect of the Postural Control Strategy on the Recognition Error of Center-of-Pressure Sway

The purpose of this study was to examine the effect of postural control strategies on the recognition error (RE) of center-of-pressure (COP) sway forward based on perceived exertion. Participants were 43 middle-aged or elderly people. We measured the maximum COP sway forward (100% center-of-pressure distance(COP-D)), 60% and 30% COP-D of 100% COP-D based on perceived exertion, and participants were classified into the good balance group and bad balance group by RE. The RE and trunk and leg angles were evaluated during COP sway forward. Results showed that RE being significantly higher for 30% COP-D and the group with a larger RE had a significantly larger trunk angle. Therefore, they may have used hip strategy predominantly to perform postural control ability, not only maximum values, but also on perceived exertion.

Immediate effects of verbal instructions with internal focus of attention and external focus of attention on forward reach movement while standing.

[Purpose] This study aimed to examine the immediate effects of verbal instructions with an internal and external focus of attention on forward reach movement while standing. [Participants and Methods] Thirty-seven healthy young males performed reach movement in three conditions: control, internal focus of attention, and external focus of attention. The measurements recorded were the movement distance of the third metacarpal bone (reach distance), the distance of the center of pressure, and the movement angles between the acromion and malleolus lateralis and between the acromion and trochanter major. [Results] Compared to the control condition, the internal focus of attention condition had a lower reach distance, angles between the acromion and malleolus lateralis and between the acromion and trochanter major, and center of pressure distance. In contrast, compared to the control condition, the external focus of attention condition showed higher reach distance and angles between the acromion and malleolus lateralis and between the acromion and trochanter major. The change rate of reach distance in the internal and external focus of attention conditions correlated significantly with the change rates of the angles between the acromion and malleolus lateralis and between the acromion and trochanter major. [Conclusion] Verbal instructions with attentional focus resulted in the simultaneous adjustment of the positional relationship between trunk and hip and immediately affected the reach distance. Our findings suggest that verbal instruction with attentional focus is an important factor affecting reach movement.

THE INFLUENCE OF HEIGHT ON TEST-RETEST RELIABILITY OF POSTURAL BALANCE MEASURES IN HEALTHY YOUNG ADULTS

Height is associated with postural balance performance. However, there has been no study on whether the test-retest reliability of the balance performance variables is related to height. The goal of our study was to analyze the effect of body height on the test-retest reliability of center of pressure (COP) variables during natural and feet-together stances in healthy young subjects. Twenty normal young men were classified into the short height group (height range, 163–174[Formula: see text]cm) and the tall height group (height range, 176–184[Formula: see text]cm) with 10 subjects each to investigate the influence of height on test-retest reliability. All subjects performed the static balance test on a commercial force plate in feet-together and natural stance conditions three times. Four variables were calculated from the COP data. COP distance, COP area, COP velocity, and COP mean frequency were selected as the postural balance variables. Intraclass correlation coefficient (ICC) was evaluated for an analysis of the test-retest reliability of each COP variable. In both stance conditions, the COP distance and the COP area in the short height group (ICC = 0.717–0.902) showed better test-retest reliability compared to those in the tall height group (ICC = 0.146–0.688). COP velocity had the highest ICC value in both stance conditions (ICC = 0.744–0.970). Additionally, the short height group showed slightly better reliability in the feet-together stance condition, whereas the tall height group showed slightly higher ICC value in the natural stance condition. These results suggest that height should be considered for a more reliable assessment of repetitive static balance performance. Our findings might be useful for the development of an optimal static balance test protocol regardless of the effect of height.

Measuring the Reliability of Postural Sway Measurements for a Static Standing Task: The Effect of Age

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.

Effects of robot-assisted trunk control training on trunk control ability and balance in patients with stroke: A randomized controlled trial.

Trunk control ability is an important component of functional independence after the onset of stroke. Recently, it has been reported that robot-assisted functional training is effective for stroke patients. However, most studies on robot-assisted training have been conducted on upper and lower extremities. The purpose of this study was to evaluate the effects of robot-assisted trunk control training on trunk postural control and balance ability in stroke patients. Forty participants with hemiparetic stroke were recruited and randomly divided into two groups: the RT (robot-assisted trunk control training) group (n= 20) and the control group (n= 20). All participants underwent 40 sessions of conventional trunk stabilization training based on the Bobath concept (for 30minutes, five-times per week for 8weeks). After to each training session, 15minutes of robotassisted trunk control training was given in the RT group, whereas the control group received stretching exercise for the same amount of time. Robot-assisted trunk control training was conducted in three programs: sitting balance, sit-to stand, and standing balance using a robot system specially designed to improve trunk control ability. To measure trunk postural control ability, trunk impairment scale (TIS) was used. Center of pressure (COP) distance, limits of stability (LOS), Berg Balance Scale (BBS) and functional reach test (FRT) were used to analyze balance abilities. In TIS, COP distance, LOS, BBS and FRT, there were significant improvements in both groups after intervention. More significant changes were shown in the RT group than the control group (p< 0.05). Our findings indicate that robot-assisted trunk control training is beneficial and effective to improve trunk postural control and balance ability in stroke patients. Therefore robot-assisted training may be suggested as an effective intervention to improve trunk control ability in patients with stroke.

Abstract TP64: Determining The Role Of Single Support Center Of Pressure Distance For Characterizing Post-stroke Walking Impairment And Response To Rehabilitation Training

Introduction: Stroke is a major cause of balance and walking impairment and is on the rise. The most widely used walking impairment measure is the 10-meter walk test (10-mWT), which provides information about walking speed but does not inform about walking kinematics or neuromuscular control. Objective: Herein, we evaluate single support center of pressure distance (SS CoP Dist), a kinematic measure of dynamic postural control and walking stability, as a complementary measure of walking impairment. We hypothesize that SS CoP Dist will be closely associated with baseline walking speed, and will improve with Backward Locomotor Treadmill Training (BLTT). Methods: Thirty-six chronic stroke survivors with residual walking impairment, based on 10-mWT speed [ mild &gt;0.8 m/s (n =7); moderate 0.4-0.8m/s (n =18); and severe &lt;0.4 m/s (n = 11)] , underwent six 30-minute BLTT sessions over two consecutive weeks. During testing (10-mWT), participants were instructed to walk as fast as possible over the gait analysis mat to capture SS CoP Dist and walking speed. Results: At baseline, there was a weak to moderate positive relationship between walking speed and SS CoP Dist (R 2 paretic = 0.22, p = 0.0036; R 2 Nonparetic = 0.44, p &lt; 0.0001). Following BLTT, SS COP Dist increased (more stable) in the mild and moderate groups [mild paretic ( p = 0.0039)/mild Nonparetic ( p = 0.0034) , moderate paretic ( p = 0.0360)/ moderate Nonparetic ( p = 0.0087)], with improved interlimb symmetry in the mild group. In contrast, no significant improvement in SS CoP Dist was seen in participants with severe walking impairment ( p = 0.3830). Training-related changes in walking speed were strongly correlated with change in SS CoP Dist (R 2 Nonparetic = 0.54, p = 0.0007). Conclusion: Our preliminary findings suggest that SS CoP Dist compliments walking speed for characterizing walking severity and response to training in chronic stroke survivors. In addition, BLTT significantly improved SS CoP Dist in mild-moderately impaired stroke survivors but not in survivors with severe walking impairment. Future well-powered, prospective studies with BLTT and other training paradigms are needed to validate these findings.

Continuous Identification of Freezing of Gait in Parkinson’s Patients Using Artificial Neural Networks and Instrumented Shoes

Freezing of gait is an episodic phenomena faced by many patients with Parkinson's disease. It is characterized by episodes during which patients are unable to generate effective forward stepping movements, despite absence of motor deficits. During the onset of the event, the patients are less stable with statistically different stride width, toe in/out angle and center of pressure distance. It has been postulated that the degree of freezing can be reduced by providing external sensory feedback to the patients during the event. However, this intervention could be facilitated by accurate identification of freezing events in real-time. This manuscript presents an Artificial Neural Network model which uses signals recorded by an instrumented footwear to predict if a walking subject is having a freezing episode. Our model presented in this paper is capable of continuously predicting freezing of gait events at a high temporal resolution of 50 Hz, using a 0.5 second window of data recorded by the instrumented shoes, with a sensitivity of 96.0±2.5%, a specificity of 99.6±0.3%, a precision of 89.5±5.9%, and an accuracy of 99.5±0.4%. This algorithm was tested with data collected from 10 patients with Parkinson's disease with frequent freezing of gait episodes.

Relation Between Reach Distance and Center of Pressure Distance for Multidirectional Reach in Hemiplegic Patients

Background Sitting balance training is an important therapy used by physical and occupational therapists who work with hemiplegic patients. Objective This study compared reach distance (Rd) and center of pressure distance (COPd) for postural control during a multidirectional reaching task in 26 patients with hemiplegia. Method Following the evaluation of trunk function, we classified subjects according to their Chedoke–McMaster assessment stage: group A, stages 5 and 6; group B, stage <4. We used a functional reach apparatus with a body pressure distribution measurement system and a video camera to measure Rd and COPd. Subjects performed multidirectional reaching tasks in the forward/front direction and toward the nonparetic and paretic sides. Resuts Group A showed moderately strong to strong positive correlations between Rd and COPd in all directions, particularly in the forward/front direction. Group B showed lower correlations between Rd and COPd, particularly during tasks where reach was directed toward the paretic side. Conclusion These results suggest that differences in trunk function had an effect on Rd and COPd during multi-directional reaching task.

Sudden visual perturbations induce postural responses in a virtual reality environment

Virtual reality environments can be manipulated allowing controlled visual disturbances. These environmental manipulations (textures, objects, and movements) can affect postural control by creating a sensory mismatch, making it possible to investigate multisensory reweighting. VR integration with motion capture equipment is relatively new; these environmental factors have not received sufficient attention to be employed in postural related research and in VR environment development. Seventeen subjects performed 48 trials of forward and backward translational optic flow in single and double support presented on a head mounted display. Each condition was presented in three different velocities: 3 m/s, 5 m/s and 8 m/s. The effect on center of pressure distance and velocity were analyzed. A repeated measures, counterbalanced experimental design was used. Center of pressure distance travelled increased in the single support condition (p < 0.001). The largest single support postural disturbance was observed in the slowest velocity and longest duration (3 m/s) and the smallest in the fastest velocity shortest duration (8 m/s). A slow optic flow velocity and higher duration of sudden visual translations generates greater disruption to postural control in single support. The velocity and duration of perturbations need to be carefully considered when studying human postural control and the design of VR environments.

Effects of Ankle Angular Position and Standing Surface on Postural Control of Upright Stance.

The purpose of the study was to investigate the effects of ankle angular position and standing surface type on static upright balance. Ten young adults stood on a force platform or on a firm wedge that induced 15° of either dorsiflexion or plantarflexion. In addition, a piece of foam was placed on top of the force platform and on the wedge. The center of pressure distance and velocity in the anteroposterior and mediolateral directions were calculated. Significantly larger magnitudes in most of the investigated variables were seen while standing with ankles in the dorsiflexion when compared with standing with the ankle joints in a natural position (p < .05). Plantarflexion increased the center of pressure anteroposterior velocity by 87% when compared with a natural stance (p < .05). Standing on the foam surfaces resulted in increases in all of the center of pressure measures by an average of 38% in all of the ankle conditions.

Bimanual load carriage alters sway patterns and step width

Many workplace falls occur during tasks involving carrying a load with both hands. Successful balance and gait during bimanual load carrying may be attributed to the adaptability of a system to navigate changing environments (e.g. construction site). This study investigates how bimanual load carrying affects adaptability of balance and gait, using 0%, 5%, and 10% of body mass in 14 young adults. Regularity of balance, and measures of range and center of pressure distance, and gait measures of stride length and step width were quantified using sample entropy. When carrying 5% load, anterior-posterior balance became less adaptable relative to 0%. As load increased from 0% to 5%–10%, step width narrowed and variability increased significantly, indicating possible increased fall risk while walking. Healthy, young adults may be at an increased risk of falls when carrying a load due to a loss in adaptability in a dynamic workplace environment.

건강한 남녀노인의 정적자세 유지를 위한 압력중심 분석

The purpose of this study was to determine a relations with age and quiet standing stability of elderlies, and to compare a standing stability of female and male elderlies through a analysis of COP(center of pressure). Healthy female(n=10, age: 76.00±4.37) and male(n=10, age: 77.70±3.30) elderlies participated for this project. The measurement was processed each distance and 95% confidence ellipse area of COP in those variations undergoing comfortable quiet upright standing with term interval 5 seconds, 6 sections, and overall 30 seconds. Correlation of Spearman analysis was performed age with COP factors by Pearson in two ways. Independent sample t-test was practiced for the comparison of female and male elderly groups with statistical significant level of .05. Significant result was not appeared in correlation age with factors such as distance and area. Female elderly group had a greater COP sways of distance and area than male elderly group during quiet upright standing, and COP distance offering significant data in terms of 0~5s, 6~10s, 16~20s, 21~25s. Standard Deviation(SD) data of female elderly group were greater than male elderly group over all of 5sec terms in COP distance and area. All of participants need the times(0~15s) for adapting of the initial stability posture, they showed decreasing of sways and firm stabilities since then. In conclusion, Stability of standing posture in elderlies can vary as the health and fitness condition of them. In other words, age is not the only balance decreasing factor in physical. And ability of upright standing from each individual had a wide gap in female elderly group. Female elderlies have more sways than male elderlies in stability posture, some intervention of prevent fall is demanded for female elderlies such as a specific balance program.

Postural instability and position of the center of pressure into the base of support in postmenopausal osteoporotic and nonosteoporotic women with and without hyperkyphosis.

In this study, we investigated the effect of bone mineral density (BMD) and thoracic kyphosis on the center of pressure (CoP) sway and its location related to the base of support (BoS). Ten young and 39 postmenopausal women voluntarily participated in this study. Postmenopausal women were divided into four groups according to the thoracic kyphosis angle (normal kyphotic < 50°≤hyperkyphotic) and T-score values. The isometric strength of the trunk and lower limb muscles were measured. The CoP postural sway was measured in a comfortable double stance position, and the location of the CoP was then determined related to the BoS. In both hyperkyphotic groups (osteoporotic and normal BMD), the strength of back extension and hip adduction showed a significant decrease compared to the normal kyphotic groups. In the osteoporotic groups (hyper- and normal kyphotic), hip abduction and ankle plantar flexion were significantly weaker than those in the nonosteoporotic groups. In both hyperkyphotic groups, velocity of the CoP displacement in the anterior-posterior (AP) direction was significantly higher than that in the young group, while, in both of the osteoporotic groups, velocity of the CoP displacement in the medio-lateral (ML) direction was significantly higher than that in the young group. In postmenopausal women, hip extensor strength negatively and significantly correlated with the CoP distance to the center of the BoS. It appears that thoracic hyperkyphosis affects postural instability in the AP direction and that a decrease of BMD affects postural instability in the ML direction.

The Relationship Between Foot Feature Parameters and Postural Stability in Healthy Subjects.

Little has been explored about the disparate contribution of medial longitudinal arch (MLA) and lateral longitudinal arch (LLA) to human gait and postural stability. This study aims to investigate the correlation of foot feature parameters including both MLA and LLA with postural stability. Thirteen young and healthy subjects participated in this study. The newly developed FFMS extracted foot feature parameters in nonweight-bearing (NWB) and weight-bearing (WB) conditions along with postural stability parameters in single-leg-standing (SLS) condition. A bivariate correlation analysis was carried out to investigate the correlation between the foot characteristics and the postural stability parameters. The foot length and width showed negative correlation with center of pressure (CoP) distance in medio-lateral (ML) and total direction, whereas the foot length in NWB and WB conditions, and the foot width in WB condition showed positive correlation with CoP distance in anterior-posterior (AP) direction. The height of the LLA curve and the area of the MLA were correlated with the postural stability parameters in AP direction. The ratios of the LLA height and area showed moderate correlation with the CoP distance in ML direction and total direction. The size of a foot, such as the length and width, is correlated with postural stability. Whereas the MLA features are associated with postural stability in AP direction, the LLA features are associated with that in ML and total direction. The findings suggest that the roles and contributions of the MLA and LLA features in and to the postural control are different.

Effects of DanceSport on walking balance and standing balance among the elderly.

BACKGROUND: Dancesport is a popular activity among older adults who look for fun and fitness in Korea. Studies reported positive sociological and psychological effects of dancesport. But, little studies were performed to evaluate the effects of dancesport on balance performances.OBJECTIVE: The objective of the present study was to evaluate the effects of dancesport for 15 weeks on walking balance and standing balance of older adults.METHODS: Older adults regularly participated in the dancesport program 3 times a week for 15 weeks. The program included Rumba, Cha-cha-cha, and Jive. They exercised the prescribed dancesport at intermediate level for 50–60 mins for each time. A total 22 reflective markers were placed on the anatomical landmarks and 8 cameras were used to measure 3-D positions of participants. Also, center of pressure (COP) data were measured to analyze standing balance using a ground reaction board at 1200 Hz for 30 seconds. One-way analysis of variance (ANOVA) was performed to test the effects of 15 weeks of dancesport on walking balance and standing balance.RESULTS: The results suggested that, after 15 weeks of dancesport participation, older adults’ walking balance (48.3 20.3 cm vs 38.2 18.2 cm) and standing balance (COP area: 189.4 85.4 mm vs 103.5 55.4mm, COP distance: 84.2 34.4 cm vs 76.5 21.4 cm) were significantly improved.CONCLUSION: Performing dancesport would require moving center of mass rapidly and frequently while maintaining posture. This may result in improving walking balance and standing balance in the present study. The study concluded that dancesport would be an effective exercise method in enhancing postural stability of older adults.

A successful backward step correlates with hip flexion moment of supporting limb in elderly people.

PurposeThe objective of this study was to determine the positional relationship between the center of mass (COM) and the center of pressure (COP) at the time of step landing, and to examine their relationship with the joint moments exerted by the supporting limb, with regard to factors of the successful backward step response.MethodsThe study population comprised 8 community-dwelling elderly people that were observed to take successive multi steps after the landing of a backward stepping. Using a motion capture system and force plate, we measured the COM, COP and COM-COP deviation distance on landing during backward stepping. In addition, we measured the moment of the supporting limb joint during backward stepping. The multi-step data were compared with data from instances when only one step was taken (single-step). Variables that differed significantly between the single- and multi-step data were used as objective variables and the joint moments of the supporting limb were used as explanatory variables in single regression analyses.ResultsThe COM-COP deviation in the anteroposterior was significantly larger in the single-step. A regression analysis with COM-COP deviation as the objective variable obtained a significant regression equation in the hip flexion moment (R2 = 0.74).ConclusionsThe hip flexion moment of supporting limb was shown to be a significant explanatory variable in both the PS and SS phases for the relationship with COM-COP distance. This study found that to create an appropriate backward step response after an external disturbance (i.e. the ability to stop after 1 step), posterior braking of the COM by a hip flexion moment are important during the single-limbed standing phase.

Unilateral Stability and Visual Feedback Body Control Improves After Three-Month Resistance Training in Overweight Individuals

ABSTRACTThe authors evaluated the effect of 3 months of resistance and aerobic training (3 sessions/week) on body balance in a group of 25 overweight and obese individuals. Prior to and after the training, they performed static and task-oriented balance tests under various conditions. Mean center of pressure (CoP) velocity and mean trace length of the CoP in the y-axis registered during a one-legged stance significantly decreased after the resistance training (19.1%, p = .024; 29.3%, p = .009). Mean trace length of the CoP in the y-axis decreased significantly also during a bipedal stance on a foam surface with eyes open and closed (10.9%, p = .040; 18.2%, p = .027). In addition, mean CoP distance and mean squared CoP distance in the anteroposterior direction during a visually guided center of mass (CoM) tracking task significantly improved (14.7%, p = .033; 28.2%, p = .016). However, only mean trace length of the CoP in the y-axis during a bipedal stance on a foam surface with eyes open and closed significantly decreased after the aerobic training (10.3%, p = .047; 16.5%, p = .029). It may be concluded that resistance training is more efficient for the improvement of the anteroposterior unilateral stability and the accuracy of the regulation of the CoM anteroposterior position than aerobic training in overweight and obese individuals.

Effects of visual feedback with a mirror on balance ability in patients with stroke.

[Purpose] This study aimed to examine the effects of a visual feedback obtained from a mirror on balance ability during quiet standing in patients with stroke. [Subjects] Fifteen patients with stroke (9 males, 6 females) enrolled in the study. [Methods] Experimental trials (duration, 20s) included three visual conditions (eyes closed, eyes open, and mirror feedback) and two support surface conditions (stable, and unstable). Center of pressure (COP) displacements in the mediolateral and anteroposterior directions were recorded using a force platform. [Results] No effect of condition was observed along all directions on the stable surface. An effect of condition was observed on the unstable surface, with a smaller mediolateral COP distance in the mirror feedback as compared to the other two conditions. Similar results were observed for the COP speed. [Conclusion] Visual feedback from a mirror is beneficial for improving balance ability during quiet standing on an unstable surface in patients with stroke.