• Title, Summary, Keyword: Human Postural Control

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Human Postural Response to Linear Perturbation (선형외란에 대응하는 인체의 자세응답 해석)

  • Kim, Se-Young;Park, Su-Kyung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.1
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    • pp.27-33
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    • 2009
  • Human postural responses appeared to have stereotyped modality, such as ankle mode, knee mode and hip mode in response to various perturbations. We examined whether human postural control gain of full-state feedback could be decoupled along with the eigenvector. To verify the model, postural responses subjected to fast backward perturbation were used. Upright posture was modeled as 3-segment inverted pendulum incorporated with feedback control, and joint torques were calculated using inverse dynamics. Postural modalities such as ankle, knee and hip mode were obtained from eigenvectors of biomechanical model. As oppose to the full-state feedback control, independent eigenvector control assumes that modal control input is determined by the linear combination of corresponding modality. We used optimization method to obtain and compare the feedback gains for both independent eigenvector control and full-state feedback control. As a result, we found that simulation result of eigenvector feedback was not competitive in comparison with that of full-state feedback control. This implies that the CNS would make use of full-state body information to generate compensative joint torques.

Identification of postural steadiness and stability: state-of-the-art (자세의 유지성 및 안정성에 관한 해석)

  • 정병용;박경수
    • Journal of the Ergonomics Society of Korea
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    • v.15 no.1
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    • pp.53-67
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    • 1996
  • Since Romberg's test in 1953, the analysis of postural sway during upright stance has been widely used as a tool for evaluating balance and disorders of the postural control system. This review describes the methods that have been used to evaluste the static and dynamic performance of the postural control system. Various identification methods of postural control system based on standing balance are discussed and measures of postural sway are described. The application areas of standign balance research, with an emphasis on postural control evaluations, are also briefly described. This review can be used to gain an understanding of the dynamics of human standing balance.

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Human Postural Balance Control by Visual Stimulation (시각 자극에 의한 신체자세 균형제어에 관한 연구)

  • 김현석;김동욱
    • Journal of Biomedical Engineering Research
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    • v.17 no.4
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    • pp.417-426
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    • 1996
  • In this paper, we report the effects of visual stimulation patterns in the postural balance control. We used the motor-driven cloth panel and HMD(Head Mounted Display) to evaluate the effect of visual stimulation patterns in the postural balance control. We also investigated the usefulness of HMD in the postural balance rehabilitation training system from the view of reducing the scale of experimental system. Our results showed that a vertical-strip visual pattern was more effective than the others in the postural balance control. It was also indicated that HMD might be applied to clinical use as a new postural balance training system.

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Analysis of Postural Stability During Continuous External Perturbations

  • Shin, Youngkyun;Park, Gu-Bum
    • 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.

Effects of Somatosensory Training on Upper Limb for Postural Control and Locomotion in Hemiplegic Stroke with Unilateral Neglect

  • Song, Bo-Kyoung
    • The Journal of Korean Physical Therapy
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    • v.27 no.5
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    • pp.332-338
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    • 2015
  • Purpose: The purpose of this study was to examine the effect of postural control and locomotion on improvement of two point discrimination (TPD), stereognosis (ST) through somatosensory training (SST) on the upper limb (UL). Methods: The subjects were 20 hemiplegia patients who have problems with unilateral neglect after stroke. The patients were divided into two groups, the experimental group (EG) and the control group (CG). In the EG, SST for TPD, ST was performed 18 times, three times a week for six weeks, together with physical therapy (PT) and occupational therapy (OT). In the CG conventional PT and OT without SST was performed for six weeks. Several assessment tools were used in comparison of groups; two point discrimination test (TPDT) on forearm (F), thenar (T), hypothenar (TH), thumb tip (TH-T), index finger tip (IN-T), stereognosis test (ST), postural assessment scale for stroke (PASS), and clinical test of sensory interaction on balance (CTSIB) and timed up and go test (TUG). Results: In the CG, conventional PT and OT resulted in statistically improved TPDT (F), ST, PASS, and TUG. In the EG, SST resulted in statistically improved TPDT (F, T, HT, TH-T, IN-T), ST, PASS, and TUG. TPDT-T, ST, and CTSIB with length of displacement with eye open (LDEO) also showed significant improvement between the groups. Conclusion: In both groups TPDT ST, PASS and TUG, and SST had effects on the UL and TPDT, ST and static postural control had greater effects compared with the PG. Therefore, we could assume that TPD and ST are very important in performing human activities including postural control and locomotion.

Open Loop Responses of Posture Complexity in Biomechanics

  • Shin, Youngkyun;Park, Gu-Bum
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.27 no.8
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    • pp.42-50
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    • 2013
  • The reactionary responses to control human standing dynamics were estimated under the assumption that postural complexity mainly occurs in the mid-sagittal plane. During the experiment, the subject was exposed to continuous horizontal perturbation. The ankle and hip joint rotations of the subject mainly contributed to maintaining standing postural control. The designed mobile platform generated anterior/posterior (AP) motion. Non-predictive random translation was used as input for the system. The mean acceleration generated by the platform was measured as $0.44m/s^2$. The measured data were analyzed in the frequency domain by the coherence function and the frequency response function to estimate its dynamic responses. The significant correlation found between the input and output of the postural control system. The frequency response function revealed prominent resonant peaks within its frequency spectrum and magnitude. Subjects behaved as a non-rigid two link inverted pendulum. The analyzed data are consistent with the outcome hypothesized for this study.

The Effect of Age and Dual Task to Human Postural Control (연령와 이중과제 수행이 자세제어에 미치는 영향)

  • Shin, Sunghoon;Jang, Dae-Geun;Jang, Jae-Keun;Park, Seung-Hun
    • Korean Journal of Sport 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.

The Effect of Ankle-Taping on Postural Balance and Lumbar Flexibility (족관절 테이핑이 자세 균형과 요부 유연성에 미치는 영향)

  • Kim, Jin-Ho;Kim, Myung-Hoon
    • 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.

Effects of Vibratory Stimulus on Postural Balance Control during Standing on a Stable and an Unstable Support (안정판과 불안정판에서 자세 균형 조절에 대한 진동자극의 영향)

  • Yu, Mi;Eun, Hey-In;Kim, Dong-Wook;Kwon, Tae-Kyu;Kim, Nam-Gyun
    • Journal of Biomedical Engineering Research
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    • v.28 no.5
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    • pp.647-656
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    • 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.