• The Journal of Korean Physical Therapy
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• v.24 no.2
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• pp.73-81
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• 2012

Purpose: The aim of the present study was to measure the standing balance symmetry of stroke patients using a force-plate with computer system, and to investigate the correlation between the standing balance symmetry and that of the walking function in stroke patients. Methods: 48 patients with stroke (34 men, 14 women, $56.8{\pm}11.72$ years old) participated in this study. Static standing balance was evaluated by the weight distribution on the affected and the nonaffected lower limbs, sway path, sway velocity, and sway frequency, which reflected the characteristic of body sway in quiet standing. Dynamic standing balance was evaluated by anteroposterior and mediolateral sway angle, which revealed the limit of stability during voluntary weight displacement. Symmetry index of static standing balance, (SI-SSB) calculated by the ratio of the affected weight distribution for the nonaffected weight distribution, and symmetric index of dynamic standing balance (SI-SDB) by the ratio of the affected sway angle for the nonaffected sway angle. Functional balance assessed by a Berg balance scale (BBS), and the functional walking by 10m walking velocity, as well as the modified motor assessment scale (mMAS). Results: Static balance scales and SI-SSB was the only correlation with BBS (p<0.05). Dynamic balance scales and SI-DSB, not only was correlated with BBS, but also with 10m walking velocity and mMAS (p<0.01). Additionally, there was a significant difference between SI-SSB and that of SI-DSB (p<0.01). Conclusion: The balance and the walking function relate to real life in the stroke showed strong relationships with the dynamic standing balance symmetry in the frontal plane and the ability of anterior voluntary weight displacement in sagittal plane.

• Safety and Health at Work
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• v.10 no.3
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• pp.321-326
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• 2019

Background: Performing cognitive tasks and muscular fatigue have been shown to increase muscle activity of the lower extremity during quiet standing. A common intervention to reduce muscular fatigue is to provide a softer shoe-surface interface. However, little is known regarding how muscle activity is affected by softer shoe-surface interfaces during static standing. The purpose of this study was to assess lower extremity muscular activity during erect standing on three different standing surfaces, before and after an acute workload and during cognitive tasks. Methods: Surface electromyography was collected on ankle dorsiflexors and plantarflexors, and knee flexors and extensors of fifteen male participants. Dependent electromyography variables of mean, peak, root mean square, and cocontraction index were calculated and analyzed with a $2{\times}2{\times}3$ within-subject repeated measures analysis of variance. Results: Pre-workload muscle activity did not differ between surfaces and cognitive task conditions. However, greater muscle activity during post-workload balance assessment was found, specifically during the cognitive task. Cognitive task errors did not differ between surface and workload. Conclusions: The cognitive task after workload increased lower extremity muscular activity compared to quite standing, irrespective of the surface condition, suggesting an increased demand was placed on the postural control system as the result of both fatigue and cognitive task.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.923-926
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• 2000

This paper concerned with the patterns of foot-floor contact and electromyography activities of the lower extremity of the body during the termination of human gait. The termination of human gait is defined as the transition from a steady-state gait to a quiet standing posture. The transition between these two states has not been extensively studied and defined. There appears to be a critical period in the gait cycle that the decision to terminate gait or continue to take an additional step must be made.

• Journal of Biomedical Engineering Research
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• v.28 no.5
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• pp.628-635
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• 2007

We studied the effect of vibratory stimulations of different leg muscles, tibialis anterior(TA) and triceps surae(TS), and plantar zones in ten healthy subjects during 1) quiet standing, 2) forward lean of body, 3) backward lean of body, 4) right lean of body, and 5) left lean of body. The experiments were performed on the force platform. The effect of vibration were measured by monitoring the area of COP(Center of pressure) sway. The subjects wore a vibratory stimulation system on foot and ankles and were given the instruction not to resist against the applied perturbations. The results show that all vibratory stimulations to lower limb muscles and plantar zones reduced the COP sway area. This reduction of the COP sway area occurred also in partial vibratory stimulations during quiet standing. In forward lean of body, vibratory stimulations to TA reduced the COP sway area. During backward lean of body, vibratory stimulations to TS reduced the COP sway area. When the subject was tilted right, vibratory stimulations to left plantar zone reduced the COP sway area. During left lean of body, vibratory stimulations to right plantar zone reduced the COP sway area. Thus, the influence of vibratory stimulations to leg muscle and plantar zones differed significantly depending on the lean of body. We suggest that the vibration stimuli from leg muscles and plantar zones could be selectively used to help maintaining postural balance stable.

• The Journal of Korean Physical Therapy
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• v.24 no.2
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• pp.134-142
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• 2012

Purpose: This study examined the effect on postural control during the stimulation of haptic touch with fingertip on the stable surface at quiet standing posture, squat flexion stage, 60 degrees squat stage and squat extension stage. Methods: The postural sway was measured on the force platform, while 30 subjects were squatting, under three different haptic touch conditions (No Touch [NT], Light Touch [LT], Heavy Touch [HT]), above the touch pad in front of their body midline. Three different haptic touch conditions were divided into 1) NT condition; squatting as right index fingers held above the touch pad, 2) LT condition (<1N); squatting as the touch pad was in contact with right index fingers pulp with a pressure not exceeding 1N and 3) HT condition; squatting as subjects were allowed to use the touch pad for mechanical support by transmitting onto it with as much force, choosing with their index fingers. Results: There was significant decrease in LT, rather than that of NT (p<0.01), and in HT, rather than that of LT (p<0.01), as the results of the distance and velocity of center of pressure (COP) in mediolateral direction at quiet standing position. In anteroposterior direction, the distance and velocity of COP in LT and HT showed significant decrease, when compared to that of the data of NT (p<0.01). There was no significant difference between the 3 conditions (NT, LT, and HT), with respect to the distance and velocity of COP in mediolateral direction, during dynamic balance (squat flexion stage, squat extension stage) (p>0.05). In anteroposterior direction, the results of the distance and velocity of COP in HT showed significant decrease when compared to that of the data of NT (p<0.05). Conclusion: Light touch, during the task, decreased the postural sway at static balance. The results suggest that haptic touch should be applied, appropriately, because it varies the effects according to different conditions.

• Physical Therapy Korea
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• v.29 no.2
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• pp.124-130
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• 2022

Background: During postural control, older adults are more dependent on proprioception than are young adults. Ankle proprioception, which plays an important role in maintaining postural balance, decreases with age. Published studies are insufficient to establish a significant age difference in postural sway resulting from the known age-related decrease in ankle proprioception and do not examine various detailed test conditions. Objects: The present study aimed to compare ankle proprioception between older and younger groups along dimensions of position vs. force proprioception and dorsiflexion vs. plantarflexion. The present study also aimed to compare postural sway between young and older women during quiet standing under two sensory conditions. Methods: We recruited seven young women aged 21-24 and seven older women aged 60-63. Ankle proprioception was assessed as the accuracy of the joint position sense (JPS) and the force sense (FS). Postural sway was assessed using center-of-pressure measurements recorded during quiet standing under two sensory positions: eyes open and eyes closed with head tilted back. Results: Older women had lower JPS in dorsiflexion and lower FS in plantarflexion than did younger women. We found no significant age differences in JPS in plantarflexion or in FS in dorsiflexion. We observed a main effect of group on postural sway in two sway parameters out of three. We observed significant differences in JPS with dorsiflexion, and in FS with plantarflexion. Conclusion: Proprioception for ankle plantar flexor decreased more significantly with aging than did that for ankle dorsiflexor, accounting for the impaired postural balance observed in older women.

• Journal of Korean Physical Therapy Science
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• v.18 no.1
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• pp.69-77
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• 2011

Background: The purpose of this study was to assessment of posture sway on static standing in the elderly. Methods: The participants aged 60 to 90 years, were divided into age such 60s, 70s and 80s and with a history of exercise, arthritis and hang on one's stick. Posture sway were analyzed using the computerized BPM system. Each test was repeated three times. All the data were expressed means and standard deviation by using SPSS 12.0 program. Results: The posture sway test according to sex showed that mean balance, sway number and frequency performance were significantly stable in men than in women. All direction frequency, sway area, sway path and max velocity were significantly unstable in 80s than 70s and 60s. The results of the posture sway test according to exercise group, arthritis and hang on one's stick group were showed that mean balance function was significantly stable in exercise group than arthritis and stick groups. The weight was showed significant correlation by mean balance, sway no, frequency, sway area, sway path and max velocity. Sway area and max velocity were not significant correlation by frequency of lateral and left, right anterior and posterior direction. Conclusion: In this study was showed that posture sway was effected from health condition of elderly.

• Korean Journal of Applied Biomechanics
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• v.23 no.2
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• pp.169-177
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• 2013

The purpose of this study is to investigate the effect of aging and dual tasking to the postural control during quiet standing. It was hypothesized that the center of pressure (COP) dynamics would be differently affected by aging and characteristics of the task. Total 60 adults (35 young adults and 25 older adults) participated in this study. They conducted two different standing tasks (dual vs. Nondual) twice in a random order. Variability, complexity, coupling and symmetric index from the left, right and overall COPs were measured by various parameters in nonlinear, linear and frequency analyses methods. Results demonstrated that older adults had worse performance in postural control with decreased complexity in overall sway movement, and increased coupling between left and right limb COP movement, even though there was no significant difference in symmetric index. These tendencies are generally clearer in nonlinear measures at the dual task condition. Results implied that older adults had compensatory strategy in dual tasking which results in simple and combined postural movement patterns.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.4
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• pp.51-58
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• 2018

PURPOSE: This study was conducted to determine if the Harrison hip score (HHS), a tool for assessing hip joint function, and the Burg balance scale (BBS), a general balance assessment tool, actually reflect the balance ability of total hip arthroplasty (THA) patients 3 months after surgery. In addition, this study investigated the initial weight distribution strategy for bilateral lower extremity after THA surgery to understand the balance of THA patients. METHODS: Fourteen 3-month THA patients performed static dual standing and sit-to-stand (STS) tasks. Ground reaction forces on each leg were collected to calculate the weight distribution symmetricity (SWD), and the HHS, functional HHS (f-HHS), and BBS were evaluated. Correlation analyses between SWD and the HHS (also f-HHS) and BBS were then applied to the THA patients. RESULTS: The correlations between functional evaluation tools (HHS, f-HHS, BBS) and SWD were weak strength for the static balance task, but moderate for the dynamic STS task. Among the evaluation tools used in the present study, f-HHS was most useful for evaluation of dynamic balance ability. CONCLUSION: The results suggest that use of HHS, f-HHS, and BBS as functional evaluation tools does not provide meaningful information regarding balance ability, but that they are useful for evaluating dynamic balance ability of THA patients. The dynamic balance ability at 3 months after THA seems to be under development.

• Journal of Biomedical Engineering Research
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• v.38 no.2
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• pp.57-61
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• 2017

The purpose of this study was to investigate the effect of direction (pitch and roll) on the perception of support surface rotation while standing. Thirty young healthy subjects participated in this study. Support surface was rotated at an unexpected instant in a very slow speed (0.2 deg/s). The direction of support surface rotation was randomly chosen among pitch (forward and backward) and roll (right and left) directions. The experiment was performed with eyes open and closed. Perception performance was evaluated by the perception threshold, defined as the rotation angle of the surface at the instant when a subject recognized that the support surface was moving. Results showed that the perception threshold was smaller for roll directions than pitch directions irrespective of vision and gender (p < 0.01). This indicates that the perception of support surface rotation is more sensitive in roll direction than in pitch direction. Among three sensory functions related to postural perception, the effect of vestibular and visual functions on the direction difference of the perception should be little because of the very slow surface rotation and independence on visual conditions. Therefore, the direction dependence of perception would have been affected mainly by the somatosensory function.