• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1066-1069
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• 2002

Dynamic postural control varies with the environmental context, specific task and intentions of the subject. In this paper, dynamic postural control against forward-backward perturbations of a platform was estimated using tri-axial accelerometers and a force plate. Ten young healthy volunteers stood upright in comfortable condition on the perturbation system which was controlled by an AC servo motor. With anterior-posterior perturbations, movements of ankle, knee and hip Joints were obtained by tri-axial accelerometers. and ground reaction forces with corresponding displacements of the center of pressure(CoP) by the force plate. The result showed that the ankle moved first and the trunk forward, which implies that the mechanism of the dynamic postural control in forward-backward perturbations, occurred in the procedure of the ankle, the knee and the hip. Knee flexion and hip extension in the period of acceleration, constant velocity and deceleration phase is very important fur the balance recovery. These responses depends on the magnitude and timing of the perturbation. From the present study the accelerometry-system appears to be a promising tool for understanding kinematic accelerative In response to a transient platform perturbation. A more through understanding of balance recovery mechanism may aid in designing methods for reducing falls and the resulting injuries.

• Physical Therapy Korea
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• v.15 no.1
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• pp.30-37
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• 2008

This study was designed to examine the effects of temporary immobilization of the ankle and knee joints on standing in healthy young adults with the use of a postural control mechanism. The subjects were twenty-four college students (12 males and 12 females, aged between 20 and 28). A Biodex balance system SD 950-302 and its software were used to measure indirect balance parameters in standing. Each subject underwent postural stability tests in 4-different joint conditions: free joints, ankle immobilization only, knee immobilization only, and ankle and knee immobilization. In addition, the postural stability test was conducted once with the subject's eyes open and once with the eyes closed conditions. For data analysis of the postural stability tests, the overall stability index, antero-posterior stability index, and medio-lateral stability index were recorded. The overall stability index (p=.000) and medial-lateral index (p=.003) were significantly greater different conditions with eyes closed in postural stability. Therefore, the eyes closed condition is expected to be used as an effective postural stability training for treatment planning in patients with unstable postures. In addition, training based on the dynamic multi-segment model can improve postural stability and is available to therapeutic programs, helping people with unstable balance to reduce their risk of falling.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1211-1214
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• 2004

High-heeled women have been identified with balance control problems. The purposes of this study were to objectively quantify the displacements and velocities of center-of-pressure (COP) of body during waist pulling and to compare the differences between barefooted and high-heeled situations. We used a waist pulling system which has three different magnitudes to sway the subjects. We found that the kinematic information of barefooted and high-heeled women's COP is very important in understanding the mechanism of postural balance control of women in every-day life. In the high-heeled's case, the displacement of COP increases in 200％ as against bare footed. Also the velocity variation of COP grows three times than the bare footed. COP analysis in postural balance study of high-heeled women is also considered useful in development of the safety systems that prevent high-heeled women from falling

• The Journal of Korean Physical Therapy
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• v.29 no.3
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• pp.135-141
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• 2017

Purpose: This study was to identify the anticipatory postural adjustment (APA) mechanism which is represented by the onset time of trunk muscles and the displacement of the center of pressure (COP) according to the different base of support (BOS) during upper extremity movement. Methods: Thirty healthy subjects (14 males, 16 females) participated in this study. The movement was performed for 10 trials during each of various BOS (shoulder - width double leg stance, narrow base double leg stance, tandem stance, non-dominant single leg stance) at the 1.2 Hz frequency. Electromyography was used to measure muscle onset time and biorescue was used to measure characteristics of the displacement of COP. Surface bipolar electrodes were applied over the right deltoid anterior, right latissimus dorsi, both rectus abdominis, both internal oblique and both erector spinae. The data were analyzed by repeated one-way ANOVA and Duncan's post hoc test. Results: The study has revealed following. There were significant differences with muscle onset time in each BOS (p<0.01). There were significant differences in characteristics of the COP in each BOS (p<0.01). Conclusion: The study found that the more narrowed the basis requires the more rapid anticipatory postural control in contralateral postural muscle when the upper extremity movement is performed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.8
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• pp.21-29
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• 2013

The functional behaviors of human standing postural control were investigated when they were exposed to long-term horizontal vibration in the sagittal plane. For complexity of human postural control, a useful alternative method that has been based on a black-box approach was taken; that is, where the feedback mechanism was lumped into a single element. A motor-driven support platform was designed as a source of vibration. The AC Servo-controlled motors produced continuous anterior/posterior (AP) motion. The data were analyzed both in the time and frequency domain. The cross-correlation and coherency functions were estimated. Subjects behaved as a non-rigid pendulum with a mass and a spring throughout the whole period of the platform motion, as consistent with the plan chosen for this study.

• Journal of Biomedical Engineering Research
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• v.18 no.2
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• pp.157-166
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• 1997

Postural balancing in human is known to be maintained by the complex mechanism coupled with cerebellum, equilibrium organ of ear, proprioception and other various organs. We developed a Computerized Balance Evaluation and Training system(COBET system) to evaluate postural control and to rehabilitate geriatrics and disabled patient. In addition, 55 normal adult were tested to investigate the influencing factors on balancing posture. For the analysis of static postural sway, areas of the moving center of pressure were calculated under 8 different positions of subjects. And subjects were also asked to follow the visual targets on monitor for the evaluation of the dynamic postural sway. In comparison of the first and the second sets of tests, there was test-retest reliability($\textit{p}$< 0.05). The controllability of the static pmtwn sway was decreased as the ages of subjects increase. When the ages of subject are over 60, the controllability was significantly decrease4 The dynamic postural sway was significantly greater in the age groups of 7th and 8th decade than the younger groups. It is concluded that COBET system is a reliable system in the evaluation of postural sway. The COBET system is considered to be a valuable training modality for the disabled patients as well as the elderly.

• The Journal of Korean Physical Therapy
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• v.15 no.2
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• pp.85-99
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• 2003

Muscle tone is the force with which a muscle resists being lengthened. Muscle tone is often tested clinically by passively extending and flexing a relaxed patient's limbs and feeling the resistance offered by the muscle. Both nonneural and neural mechanism contribute to muscle tone. Muscle tone is the mechanisms that contribute to the generation of tone in individual muscles when a person is in a relaxed state. This background level of activity changes in a certain antigravity posture muscle when we stand upright, thus counteracting the force of gravity. This increased level of activity in antigravity muscles is known as postural tone. The evidence from experiments showing that lesions of the dorsal(sensory) roots of the spinal cord reduced muscle(postural) tone is influenced by inputs from the somatosensory system. Patients with neurological damage have several state of muscle(postural) tone, which display from flaccidity to rigidity. This review article deal with muscle tone and somatosensory system acting on this. The understanding about this contribute to a better therapeutic approach for the rehabilitation of patients to have an abnormal muscle(postural) tone due to neurological damage.

• The Journal of Korean Physical Therapy
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• v.25 no.5
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• pp.288-296
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• 2013

Purpose: This study was conducted in order to determine whether mechanical horseback-riding training depending on velocity can improve vestibular function and static postural balance on standing in healthy adults. Methods: For evaluation of vestibular function, electrooculography (EOG) of vertical and horizontal was performed for identification of the motion of eyes. For evaluation of static postural balance, COP distance, time spent on the sharpened Romberg test with neck extension (SRNE) were measured. Measurements were performed three times before training, three weeks after training, and six weeks after training. Participants were randomly assigned to three groups: fast velocity-mechanical horse -riding training (FV-MHRT, n=12), moderate velocity-mechanical horse-riding training (MV-MHRT, n=12), and slow velocity-mechanical horse-riding training (SV-MHRT, n=12). Results: According to the result for vertical, horizontal EOG, there was significant interaction in each group in accordance with the experiment time (p<0.05). The FV-MHRT group showed a significant decrease compared with the MV- MHRT, SV-MHRT groups (p<0.05). According to the result for static postural balance, the time spent, COP distance in SRNE showed significant interaction in each group in accordance with the experiment time (p<0.05). The time spent on the SRNE showed a significant increas in FV-MHRT, SV-MHRT (p<0.05). The COP distance of SRNE showed a significant increase in MV-MHRT (p<0.05). Conclusion: The MHRT velocity activated mechanism of vestibular spinal reflex (VSR), vestibular ocular reflex (VOR), also helped to strengthen vestibular function and static postural balance. In addition, it should be applied to different velocity of MHRT according to the specific purpose.

• Journal of Biomedical Engineering Research
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• v.24 no.5
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• pp.435-442
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• 2003

In this paper, biomechanical aspects of dynamic대학교postural responses against forward perturbations were experimentally determined simultaneous measurements of joint angles, accelerations. EMG activations, center of pressure(CoP) movements and ground reaction forces(GRF), Thirteen young healthy volunteers, stood on a flat platform, were translated into the forward direction by an AC servo-motor at two separate velocities(0.1m and 0.2m/s). In order to recover postural balance against the forward perturbation, joint motions were observed in the sequence of the ankle dorsiflexion, the knee flexion and then the hip flexion during the later acceleration phase. Both acceleration patterns at the heel and the sacrum were shown the forward acceleration pattern during the later acceleration phase and early of constant velocity phase as increasing platform velocity, respectively. Tibialis anterior(TA) for the ankle dorsiflexion and biceps femoris(BF) for the knee flexion. the primary muscle to recover the forward perturbation, was activated during the half of acceleration phase. Ankle strategy was used for slow-velocity perturbation, but mixed strategy of both ankle and hip used for the fast-velocity perturbation. In addition, parameters of perturbation such as timing and magnitude influenced the postural response against the perturbation.

• Journal of TMJ Balancing Medicine
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• v.8 no.1
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• pp.16-23
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• 2018

Positional Release Techniques (PRTs) are an umbrella term for manual therapies harnessing spontaneous musculoskeletal balancing mechanism of the body facilitated by finding and maintaining therapeutic position. PRT has its origin in the Strain Counterstrain (SCS) technique by Dr. Jones but encompasses diverse related techniques that stemmed off from the SCS. PRT emphasizes postural balance within the body and innate healing potential of the body including the postural balance of the temporomandibular joint (TMJ). This study briefly reviews concepts, history, and contemporary study reports on PRT with a focus on the yin-yang balance based approach of PRT.