• Korean Journal of Applied Biomechanics
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• v.26 no.1
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• pp.115-126
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• 2016

Objective: The purpose of this study was to investigate plantar foot pressure and static balance according to the type of insole in the elderly. Methods: Thirteen elderly (mean age: $67.08{\pm}2.25years$, mean height: $159.63{\pm}9.64cm$, mean body weight: $61.48{\pm}9.06kg$) who had no previous injury experience in the lower limbs and a normal gait pattern participated in this study. Three models of insoles of the normal, 3D, and triangle types were selected for the test. The Pedar-X system and Pedar-X insoles, 3.3 km/h of walking speed, and a compilation of 20 steps walking stages were used to analyze foot-pressure distribution. Static balance test was conducted using Gaitview AFA-50, and balance (opening eyes, closing eyes) was inspected for 20 s. One-way ANOVA was conducted to test the significance of the results with the three insoles. p-value of less than .05 was considered statistically significant. Results: The mean foot pressure under the forefoot regions was the lowest with the 3D insole during treadmill walking (p<.05). The mean value under the midfoot was the highest with the 3D insole (left: p<.05, right: p<.01). The mean value under the rearfoot was the lowest with the 3D insole (p<.001). The maximum foot pressure value under the foot regions was the lowest on both sides of the forefoot with the 3D insole. A statistically significant difference was seen only in the left foot (p<.01). The maximum value under the midfoot was the highest with the 3D insole (p<.001). No statistically significant difference was detected on the values under the rearfoot. In the case of vertical ground reaction force (GRF), statistically significant difference was seen only in the left side rearfoot (p<.01). However, static balance values (ENV, REC, RMS, Total Length, Sway velocity, and Length/ENV) did not show significant differences by the type of insole. Conclusion: These results show that functional insoles can decrease plantar pressure and GRF under the forefoot and rearfoot. Moreover, functional insoles can dislodge the overload of the rearfoot and forefoot to the midfoot. However, functional insoles do not affect the static balance in the elderly.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1740-1748
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• 2011

The purpose of this study was to investigate effects of the long-term high-frequency transcutaneous electrical nerve stimulation(TENS) on the spasticity and the balance in chronic stroke patients. Twenty-six subjects with spasticity over lower limbs were allocated randomly into two groups under standard rehabilitation: (1) TENS group, (2) placebo-TENS group. TENS stimulation was applied on the both the gastrocnemius for 30 minutes, 5 days a week for 4 weeks(100 Hz, 0.25 ms, 2 times sensory threshold). The Modified Ashworth Scale(MAS) and Hand-held manual muscle tester were used to assess the ankle plantarflexor spasticity. Balance function under three conditions was measured by using force-plate and the amount of postural sway was assessed; in (1) the condition of standing with eyes opened, (2) with eyes closed and (3) the condition of standing on unstable surface with eyes opened. Both groups showed significant improvement in spasticity and balance function after treatment for 4 weeks(p<.05). Especially, TENS group showed a significant reduction of spasticity compared to placebo-TENS group(p<.05). These results suggested that additional stimulation of a long-term high-frequency TENS to standard rehabilitation induced an improved balance function and a spasticity reduction. The long-term application of high-frequency TENS will be an effective intervention for reducing spasticity and increasing balance ability in the chronic stroke patients.

• Physical Therapy Korea
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• v.7 no.2
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• pp.1-19
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• 2000

Decreased equilibrium in standing and walking is a common problem associated with hemiparesis secondary to cerebral vascular accident. In patients with hemiplegia, postural sway is increased and often displaced laterally over the non-affected leg, reflecting asymmetry in lower extremity weight bearing during standing balance. Human balance is a complex motor control task, requiring integration of sensory information, neural processing, and biomechanical factors. Limits of stability (LOS) is a one of the biomechanical factors. The purposes of this study were to establish the influence of asymmetrical weight-bearing on the LOS of independent ambulatory hemiparetic patients. The subjects of this study were 29 hemiparetic patients (18 males, 11 females) being treated as admitted or out patients at Young-Nam University Hospital and Taegu Catholic University Hospital, all of whom agreed to participate in the study. Participants were asked to lean and displace their center of gravity (COG) as far as possible in directions to the sides and front of the body. The LOS and weight-bearing ratio were measured with a Balance Performance Monitor (BPM) Dataprint Software Version 5.3. In order to assure the statistical significance of the results, the independent t-test and a Pearson's correlation were applied at the .05 and .01 level of significance. The results of this study were as follows: 1) There were statistically significant differences in anteroposterior LOS according to the cause of brain demage (p<.01). 2) There were statistically significant differences in mediolateral LOS according to the hemiparetic side (p<.05). 3) There were statistically significant differences in anteroposterior and mediolateral LOS according to the brain operation (p<.01). 4) The mediolateral LOS significantly correlated with weight-bearing ratio (p<.01).

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.8 no.1
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• pp.51-56
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• 2010

Purpose : This study identifies the effect of ankle-taping on limb asymmetry, postural sway and lumbar flexibility. Ankle-taping was applied for participants of this study and the results were compared to the control group. Methods : This study targets 46 adults, in which 25 composed the test group and 21 composed the control group. All participants were interviewed. For the test group, inflexible tapes of 5mm width were applied as designed by Danaka Nobudaka while the tapes for the control group were arranged in a symmetric direction to the direction of the test group. Postural balance was measured using Mediance (Human Tech Inc, Korea) and to identify lumbar flexibility, the trunk flexion is targeted. Results : 1. The postural inclination of both the groups decreased, but a statistically significant difference is not found (p>0.05). 2. Both the groups increased, but no statistically significant difference is found (p>0.05). 3. Both the groups increased, and a statistically significant change is found (p<0.05). Conclusion : As demonstrated in the results above, ankle taping is effective for lumbar flexibility as well as stability of ankle joints regardless of the direction of taping. It also suggests that ankle taping is helpful for health management of athletes and the public. However, as the results are limited in that they were obtained 10 minutes after taping, it is hoped that further studies will follow.

• Physical Therapy Rehabilitation Science
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• v.8 no.1
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• pp.40-44
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• 2019

Objective: The purpose of this study was to examine the changes in postural stability according to ankle fixation in healthy university students. Design: Cross-sectional study. Methods: Thirty healthy subjects (15 males and 15 females, 20.13 years, 167.49 cm, 65.87 kg) were recruited on a voluntary basis. The BT4 system (HUR Laps Oy, Tampere, Finland) was used to measure the static (standing posture with eyes open and eyes closed) and dynamic (external perturbation and limits of stability (LOS) in the forward, backward, left, and right side) balance abilities. External perturbation was measured by the subject's postural sway velocity and area for 20 seconds after being impacted by a gym ball. Static and dynamic stabilities were measured with ankle joint fixation and non-fixation conditions. Ankle fixation was provided using Mueller tape on both ankle joints. Results: For static stability under the standing posture, there was no significant difference between standing with ankle joint fixation and non-fixation conditions. However, dynamic stability (external perturbation and LOS in the forward, backward, left, and right side) was significantly higher in the standing with the non-fixation condition compared to the standing with ankle joint fixation condition (p<0.05). Conclusions: Our results reveal that ankle joint fixation can influence dynamic stability during standing. Thus, we believe that this result provides basic information for making improvements in postural control and may be useful in balance training for fall prevention.

• Physical Therapy Rehabilitation Science
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• v.9 no.1
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• pp.10-17
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• 2020

Objective: Hallux valgus (HV) is a common musculoskeletal deformity that is accompanied with pain and continues to decrease one's quality of life and ability to perform daily life activities by affecting gait and static stability. Therefore, this study aimed to investigate the effect of the angle of HV (HVA) and to compare the one-legged stance and gait parameters in young adults with less HV and severe HV. Design: Cross-sectional study. Methods: Forty young adults were divided into two groups, where HVA ≥15° (n=20) was defined as HV, and HVA <15° (n=20) was defined as normal. For balance ability, the center of pressure (COP) path, velocity, length of axis of the COP path, deviation of the x-axis and y-axis, and percentage of foot pressure were measured, and gait, the foot rotation angle, step length, percentage of each phase of the gait cycle, time change from the heel to forefoot, and maximum pressure of the forefoot and midfoot were measured. Results: Significant differences were found in sway length and time change from heel to forefoot during walking between the normal and HV groups (p<0.05). Most parameters were not associated with the HVA, but parameters such as length of axis and time to change from heel to forefoot were significantly associated with the HVA (p<0.05). Conclusions: These results suggest that most one-legged stance and gait parameters were not significantly affected by the HVA in young adults; therefore, future studies are needed in order to address other dynamic parameters and other methods of gait analysis for detecting clinically meaningful conditions.

• Journal of Biomedical Engineering Research
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• v.30 no.3
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• pp.247-254
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• 2009

We studied the postural response induced by plantar sole vibration with various frequencies(20, 60, 100Hz) and vibration zone(the anterior and posterior foot zone) of both soles during standing. Eight healthy young adults were exposed to 15s periods of plantar sole vibration while blindfolded. Body sway(COM, center of mass), the angle of neck, trunk, hip, knee, ankle and EMG of four lower limb muscles(tibialis anterior, lateral and medial gastrocnemial, soleus muscle) were recorded during 15s plantar sole vibration using 3D motion analysis system. Simulating each zone separately resulted in spatially oriented body tilts; oppositely directed backward and forward, respectively, the amplitude of which was proportional to the vibration frequency. EMG activity of lower limb muscles also varied according to the direction of the vibration zone and linearly according to the frequency. These findings led us to consider the plantar sole vibration as useful method of postural balance control and adjustment.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.3
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• pp.259-264
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• 2016

Purpose: To establish the cause of decrease in body stability and to analyze the effects on sensory organs maintaining static balance according to the induced astigmatic blur. Methods: Twenty subjects (10 males, 10 females; mean age, $23.40{\pm}2.70years$) were participated in this study. To induce myopic simple astigmatism, the axis directions of cylindrical lenses were placed $180^{\circ}$ on both eyes (with-the-rule), $90^{\circ}$ on both eyes (against-the-rule), and $45^{\circ}$ on both eyes (oblique). Cylindrical lenses of +0.50, +1.00, +1.50, +2.00, +3.00, +4.00, and +5.00 D were used to increase astigmatic blur in each astigmatism types. General stability (ST) and sway power (SP) in frequencies by each sensory organs were analyzed using the TETRAX biofeedback system. Results: ST in the all astigmatism types were raised with increase of astigmatic blur compared to full corrected condition, but a significant difference only showed in the induced oblique astigmatism. According to the results of correlation analysis between ST and SP in the each frequencies with increase of astigmatic blur, the causes of increased ST in the induced oblique astigmatism showed to have a high correlation in order of somatosensory system (high-medium frequency), central nervous system (high frequency), peripheral vestibular system (low-medium frequency), and visual system (low frequency). Conclusions: The visual information by uncorrected oblique astigmatism may disturb the normal functions of all sensory organs maintaining body balance, consequently, the body stability can be reduced. Therefore, optimal correction of astigmatism can play an important role for reducing the instability of body balance.

• Safety and Health at Work
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• v.6 no.3
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• pp.206-210
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• 2015

Background: Fatigue has a strong impact on workers' performance and safety, but expedient methods for assessing fatigue on the job are not yet available. Studies discuss posturography as an indicator of fatigue, but further evidence for its use in the workplace is needed. The purpose of the study is to examine whether posturography is a suitable indicator of fatigue in clerical workers. Methods: Thirty-six employees (${\emptyset}$ 34.8 years, standard deviation = 12.5) participated in postural tasks (eyes open, eyes closed, arm swinging, and dual task) in the morning and afternoon. Position of their center of pressure (COP) was registered using a Nintendo Wii Balance Board and commercial software. From registered COP time series, we calculated the following parameters: path length (mm), velocity (mm/s), anterior-posterior variance (mm), mediolateral variance (mm), and confidence area ($mm^2$). These parameters were reduced to two orthogonal factors in a factor analysis with varimax rotation. Results: Statistical analysis of the first factor (path length and velocity) showed a significant effect of time of day: COP moved along a shorter path at a lower velocity in the afternoon compared with that in the morning. There also was a significant effect of task, but no significant interaction. Conclusion: Data suggest that postural stability of clerical workers was comparable in the morning and afternoon, but COP movement was greater in the morning. Within the framework of dynamic systems theory, this could indicate that the postural system explored the state space in more detail, and thus was more ready to respond to unexpected perturbations in the morning.

• Journal of the Korea Society of Computer and Information
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• v.16 no.1
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• pp.117-124
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• 2011

This study was realized the home network system for home care by bio-physical sensor system, to convey for the remote physical signal. The composition condition has four functions of displacement point for a Vision, Somatosensory, Vestibular and CNS that the basic measurement used to a Heart Rate, Temperature, Weight. Physical signal are decided to search a max and min point with adjustment of 0.01 unit in the reference level. There were checked physical condition of body balance to compounded a physical neuroceptor of sensory organ for the measurement such as a Vision, Somatosensory, Vestibular, CNS, BMI. There are to check a health care condition through a combination of physical organ with a posturography of a exercise. The service of home network system can be used to support health care management system through health assistants in health care center and central health care system. It was expected to monitor a physical parameter for the remote control health management system.