• 대한의용생체공학회:의공학회지
• /
• 제30권3호
• /
• pp.255-262
• /
• 2009

The present study analyzed the association between postural control and electrical stimulation by measuring body sway when use the electrical stimulations were applied to different stimulation zones in lower limbs. The subjects were 14 young adults and were, tested for two different visual condition: eyes open and eyes closed. The experiments were also performed in two different stance case: one legged stance and two legged stance while electrical stimulations were applied concurrently or individually to tibialis anterior and triceps surae. Postural responses were assessed by analyzing COP sway path, sum of COP sway measured by a forceplate. The results showed that the direction of the COP shift changed in accordance with the direction of stimulation and showed sensory adaptation as the experiment progressed for two legged stance case. For one legged stance case, concurrent electrical stimulation both sides of muscles was found to be effective for enhancement of postural balance control.

• 대한물리치료과학회지
• /
• 제29권3호
• /
• pp.56-62
• /
• 2022

Background: The purpose of this study was to investigate the effects of ankle joint immobilization on postural balance during quiet standing. Design: Cross-sectional study Methods: Twenty-seven healthy subject participated in this study. The subjects performed to stand quietly for 30s in eyes open on the platform with three different conditions. The sway length, sway area and sway velocity of center of gravity (COG) displacement and limit of stability (LOS) was measured using the balance platform. Repeated measured ANOVA was used to compare the postural balance parameters depending on three different ankle immobilized conditions. Results: Sway length, sway area and sway velocity of the COG displacement with bilateral ankle immobilized condition was significantly increased compared to those of the other two conditions(p<0.05). All directions of LOS with bilateral ankle immobilized condition were significantly decreased compared to those of the other two conditions. Conclusion: These findings suggest that ankle joint immobilization could be one of the factors that interfere the maintaining of the postural balance in quiet standing.

• 대한의용생체공학회:의공학회지
• /
• 제28권5호
• /
• pp.647-656
• /
• 2007

The purpose of this study was to analyze the effects of vibratory stimulus as somatosensory inputs on the postural control in human standing. To study these effects, the center of pressure(COP) was observed while subjects were standing on a stable and an unstable support with co-stimulated mechanical vibrations to flexor ankle muscles(tibialis anterior tendon, achilles tendon) and two plantar zones on both foot. The COP sway measurement was repeated twice in four conditions: (1) with visual cue and vibration, (2) without visual cue and vibration, (3) with visual cue and without vibration, (4) without visual cue and with vibration. The calculated parameters were the COP sway area and the distance, the median frequency and the spectral energy of COP sway in three intervals $0.1{\sim}0.3,\;0.3{\sim}1,\;1{\sim}3Hz$. The results showed that vibratory stimulus affect postural stability. The reduction rate of the COP sway with vibratory stimulus were higher on the unstable support because the effect of postural stability increases when afferent nervous flow is more activated by vibration on unstable support. If unclear visual or vibratory information is received, one type of information is compared with the other type of sensory information. Then the input balance between visual and vibratory information is corrected to maintain postural stability. These findings are important for the rehabilitation system of postural balance control and the use of vibratory information.

• The Journal of Korean Physical Therapy
• /
• 제22권5호
• /
• pp.63-70
• /
• 2010

Purpose: In this study, children with cerebral palsy were treated for 8 weeks using horse riding trunk proprioception, stability and posture to investigate the effect of hippotherapy in the field of physical therapy. Methods: A total of 18 subjects were divided into an experimental group treated by horseback riding and a control group. Both groups were evaluated pre- and post-treatment. Trunk proprioception was measured three times in the sitting position with their eyes and ears closed to reach the target position the angle error of the mean was calculated. Trunk stability was measured using a forceplate and the data were used to calculate the postural sway path & postural sway velocity. Posture was evaluated using the Posture Assessment Scale (PAS). Results: After hippotherapy, the experimental group showed a significant improvement in trunk proprioception, stability and posture (p<0.05), but the control group improved in posture only (p<0.05). Trunk proprioception, stability and posture was significantly different between the two groups (p<0.05). Conclusion: Eight weeks of hippotherapy is effective in improving trunk proprioception, stability, and posture. Research using this therapy should be studied further as a possible new therapeutic approach in the field of physical therapy.

• 제어로봇시스템학회논문지
• /
• 제13권9호
• /
• pp.843-850
• /
• 2007

This paper proposes a somatosensory stimulation system for the improvement of postural stability using vibration as somatosensory stimulation. This system consists of vibratory stimulation and postural response measurement. To evaluate this system, the center of pressure(COP) was closely observed in turn with simultaneous or separate mechanical vibratory stimulations to flexor ankle muscles (tibialis anterior, triceps surae) and two plantar zones on both feet while standing on a stable and an unstable support. The simultaneous vibratory stimulations cleared influenced postural stability and the effects of vibrations were higher with the unstable support. In separate vibratory stimulations, the extent of the COP sway reduced when the direction of the vibratory stimulations and that of the inclination of body coincided for flexor ankle muscle stimulations. In the contrary, the extent of the COP sway increased when the direction of the stimulations and that of body inclination coincided for plantar zone stimulations. These results can be useful for the development of rehabilitation systems that utilizes somatosensory inputs for postural balance.

• 한국전문물리치료학회지
• /
• 제15권4호
• /
• pp.18-26
• /
• 2008

The present study was aimed at investigating the postural control ability of volleyball players with functional ankle instability. The subjects were 26 male volleyball players were divided into 2 groups (13 subjects with functional ankle instability and 13 subjects with ankle stability) who could evaluate Questionnaire. All the male participants were tested by a Balance Master System. This study were to measure of static balance ability, dynamic balance ability, motor function the difference between functional ankle instability group and control group. Ankle instability group and stable group in postural sway ($^{\circ}/sec$) on film surface with eye closed in modified clinical test sensory interaction on balance, and left unilateral stance with eye opened and closed were significantly different (p<.05). The ankle instability group and stable group in limit of stability were significantly different (p<.05). The ankle instability group and stable group in left/right rhythmic weight shirt were significantly different (p<.05). The ankle instability group and stable group in turn time (sec) & turn sway ($^{\circ}$) during step/quick turn and end sway ($^{\circ}/sec$) in tandem walk were significantly different (p<.05). This study showed that volleyball players with functional ankle in stability were effected postural control ability by static balance & dynamic balance ability. Further study is needed to measure various athletic with functional ankle instability for clinical application.

• 대한의용생체공학회:의공학회지
• /
• 제30권6호
• /
• pp.521-528
• /
• 2009

This study is about to evaluation of postural stability according to characteristics of electrical stimulation on the ankle muscles. We measured body sway(center of pressure, COP) when various parameters of electrical stimulation was applied to ankle muscles in stable and unstable posture. Subjects consisted of 10 young adults, and electrical stimulation was delivered on right and left of tibialis anterior and Achilles tendon. The body sway was measured during electrical stimulation of three duty cycle and frequencies in stable posture and three amplitudes of sensory threshold in unstable posture. Consequently, the COP Shift is higher during electrical stimulation of 1/30(duty ratio) and 100Hz(frequency) in stable posture. In unstable posture, 100% amplitude of sensory threshold induced postural stability. These findings are important for the rehabilitation system of postural stability and the use of electrical stimulation as somatosensory information.

• 대한의용생체공학회:의공학회지
• /
• 제28권5호
• /
• pp.628-635
• /
• 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
• /
• 제13권2호
• /
• pp.381-397
• /
• 2001

In the patients with hemiplegia caused by stroke and TBI. postural sway is increased and open displaced laterally over the non-affected leg, reflecting asymmetry in weight bearing on lower extremities during standing balance. Recovery of symmetric weight bearing and postural stability is an important aim in physical therapy. Plastic AFO has been used for hemiplegic patients in order to help their abnormal walking patterns. Past studies have mainly focused on the AFO influences on hemiplegic walking patterns without balance function approaches. The purpose of this study was to identify the immediate effects of plastic AFO and shoes on the static balance in hemiplegic patients. The scale for static balance were weight bearing on affected leg(%), sway area(mm2), sway path(mm), maximal sway velocity(mm/s), anteroposterior sway angle($^{\circ}$ ), and lateral angle($^{\circ}$ ). Seventeen hemiplegic patients participated in this study: 13 men and 4 women, with an average age of 50.18 years. Static balance was measured using BPM(balance performance monitor; dataprint software version 5.3) under four standing condition namely bare-foot standing. standing in shoes, standing with AFO, and standing in shoes with AFO. In order to assure the statistical significance of the results, an one-way ANOVA, the independent t-test. and a pearson's correlation were applied at the .05 level of significant. The results of this study were as follows: 1) There were statistically significant differences in weight bearing(%) on the static balance between affected leg and non-affected leg(p<.01). 2) There were statistically significant differences in sway reverse frequence(Hz) in standing with AFO between affected leg and non-affected leg(p<.05). 3) Sway area(mm2) on standing in shoes with AFO was lower than bare-foot standing(p<.05), Lateral sway angle($^{\circ}$ ) on standing in shoes with AFO was lower than bare-foot standing and standing in shoes(p<.05). 4) Weight bearing in affected leg was not significantly correlated with postural sway.

• The Journal of Korean Physical Therapy
• /
• 제27권5호
• /
• pp.292-298
• /
• 2015

Purpose: The purpose of this study was to examine the effects of dual tasks on balance and postural control during standing in patients with cerebellar ataxia (CA). It was hypothesized that CA patients would exhibit different sway characteristics of the center of mass (COM) depending on the complexity of the secondary cognitive tasks compared with normal control subjects. Methods: A total of 8 patients with CA and age-matched healthy control subjects participated in this study. They were instructed to perform two balance tasks (non-dual and dual movement) with 3 different complexity of dual tasks. Range, variability, and velocity of COMs were measured. Results: According to the results CA patients showed deficits in balance and postural control with increased dual-task complexity during the static balance task in saggital sway movements. However, there was no significant difference in static balance in frontal sway. With higher difficulty in the cognitive task, CA patients took longer to stabilize their body center, while normal control subjects showed no change between conditions. In addition, CA patients had a greater COM resultant velocity during recovery in the dual-task condition compared with the single-task condition. These findings indicate that CA patients had defendable compensatory strategies in performing dual tasks. Conclusion: In conclusion, CA patients appeared to manage the priority to balance and postural control. Particularly in a situation with a postural threat such as when potential consequences of the loss of stability increase, they appeared to prioritize the control of balance and posture over the performance of the secondary task.