• Physical Therapy Rehabilitation Science
• /
• v.8 no.1
• /
• pp.32-39
• /
• 2019

Objective: The aim of this study is to investigate the effects of whole body vibratory stimulation on muscle strength, balance, and fall efficacy among super-aged women. Design: Randomized controlled trial. Methods: Twenty-eight super-aged women over 80 years of age were assigned to either the experimental group (n=14) and control group (n=14). The experimental group received an exercise program that used the whole body vibratory stimulation with a frequency of 30 Hz and amplitude of 3 mm, and the control group received an exercise program without vibratory stimulation. Intervention was provided for 4 weeks, 3 sessions per week, and 30 minutes per session. In order to measure lower extremity muscle strength the 30-second chair stand test (CST) was used. The Berg Balance Scale (BBS) was used to measure dynamic balance. Static balance was measured by tracking the path length, velocity, and area of the center of pressure (CoP). The Falls Efficacy Scale (FES) was used to measure the subjects' fear of falling. Results: Both the experimental and control group demonstrated statistically significant increase in muscle strength, dynamic balance, and fall efficacy (p<0.05). Only the experimental group showed significant improvements in static balance before and after the intervention (p<0.05). The experimental group showed significantly greater improvements in CST, BBS, and CoP (path length, velocity) than control group (p<0.05). Conclusions: Whole body vibratory stimulation exercise is shown to be a safe and appropriate physical therapy intervention method to enhance muscle strength, balance, and fall efficacy of super-aged women.

• Journal of Korean Medical Ki-Gong Academy
• /
• v.22 no.1
• /
• pp.1-27
• /
• 2023

Objective : This paper provides a narrative review of the research literature on the neurophysiological and neurochemical mechanisms of local vibration while studying the treatment principles and mechanisms of Whidam's vibrator Sugi therapy. Methods : Searches related to vibration therapy research were conducted in PUBMED using "Vibration", "Whole Body Vibration", "Localized Vibration", and "Focal Vibration". The Conditions were limited to review and systematic review. Results : Roberto Casale's paper was selected as an inquiry task and reviewed critically and narratively by referring to other papers. The stimulation process of local vibration (LV) was broadly classified into receptor transmission (pain reception phase), ascending sensory pathway to the spinal cord (segmental phase), and action of the cortex and subcortical structures (systemic control phase) according to the pain pathway. In addition, the role of C-tactile mechanoreceptors, changes in neurotransmitters and neurohormones, LV stimulation below perception threshold (lower threshold), pain control and kinesiologic illusions were specially addressed. In addition, the expression and function of Piezo Channels were added to supplement the human pain and tactile sensing mechanism. Conclusions : LV exerts pain control mechanisms through different interactions that can interfere with pain transmission and pain perception. Since LV provides sufficient neurophysiological reasons for clinical application, it is necessary to expand the use of Whidam's vibrator Sugi therapy to a wider range of clinical applications.

• Physical Therapy Korea
• /
• v.28 no.2
• /
• pp.108-116
• /
• 2021

Background: Whole-body vibration (WBV) has been used to alleviate proprioceptive damage by musculoskeletal and neurological conditions. However, no study has determined whether wearing shoes while applying WBV can affect proprioception precision of the knee joint. Objects: This study aimed to determine the differences in the proprioceptive precision of the knee joint before and after WBV and to compare the proprioceptive precision of the knee joint between barefoot and shoe-wearing conditions. Methods: This study recruited 33 healthy participants. A passive-to-active angle reproduction test was used to measure the proprioception precision of the knee joint using an electrogoniometer, and the target angle was set to a knee flexion of 30°. Proprioception precision was calculated using the error angle (angular difference from 30°). Proprioceptive precision was measured in weight-bearing and non-weight-bearing positions before and after applying WBV for 20 minutes at 12 Hz in barefoot and shoe-wearing conditions. Mixed repeated analysis of variance was used to determine the differences in changes in the proprioceptive precision of the knee joint according to foot conditions. Results: There were significant improvements in the weight-bearing (p = 0.002) and non-weight-bearing (p < 0.001) proprioceptive precision of the knee joint after applying WBV. However, there was no significant difference in the change in proprioceptive precision of the knee joint after applying WBV between the barefoot and shoe-wearing conditions. Conclusion: WBV stimulation had an immediate effect on improving the proprioceptive precision of the knee joint. However, foot conditions (barefoot or shoe-wearing) during WBV application did not influence the proprioceptive precision of the knee joint.

• Interaction and multiscale mechanics
• /
• v.3 no.4
• /
• pp.365-372
• /
• 2010

Station is an important building in high-speed railway, and its vibration and noise may significantly affect the comfort of waiting passengers. A coupling vibration model for train-structure system is established to analyze and evaluate the vibration level of a typical waiting hall under dynamic train load. The motion of a four-axle vehicle with two suspension system is modeled in multi-body dynamics with linear springs and dampers employed. The station is modeled as a whole finite element structure which is 113 m in longitudinal and 163.5 m in lateral, and the stiffness of the station foundation is considered. According to the assumptions that both wheel and rail are rigid bodies and keep contact to each other in vertical direction, and the wheel/rail interaction and displacement coordination in horizontal direction is defined by the simplified Kalker creep theory, the vehicle spatial vibration model has 27 degrees-of-freedom. An overall analysis procedure is made of the train moving through the station, by which the dynamic responses of the train and the station are calculated. According to the comparison between analysis and test results, the actual connection status between different parts of the station is estimated and the vibration level of the waiting hall is evaluated.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2000.04a
• /
• pp.81-88
• /
• 2000

Unlike structures in the air, the vibration analysis of a submerged or floating structure such as offshore structures or ships is possible only when the fluid-structure interaction is understood, as the whole or part of the structure is in contact with water. Specially, the importance of the added mass is not necessary to say like the submerged vehicle, all of the hull body, is positioned in the water. This paper introduce two method to find natural frequency in consideration of fluid-structure modal coupled vibration analysis. The purpose of this study is to analyze of the vibration characteristic of submerged vehicle to obtain the anti-vibration design data, which could be used in the preliminary design stage data. Underwater pressure hull of submerged vehicle is used as the model of this study. The F.E.M model is meshed by shell and beam element. Also, considering of the inner hull weight, mass element is distributed in the direction of hull length. Numerical calculations are accomplished using the commercial B.E.M code. The characteristics of natural frequency(eigenvalues), mode shape(eigenvectors) and frequency-displacement response are analyzed. The results of this study will be used as the useful design data in preliminary anti-vibration design stage.

• Proceedings of the KIPE Conference
• /
• 1998.07a
• /
• pp.95-98
• /
• 1998

Applying the magnetically levitated transportation system, which is noncontact bearing system, to solve the problems such as transformation of original form or flaw of iron plate caused by transportation of thin iron plate which required high quality as body of motor vehicle, materials of electronic devices etc.. Magnetic saturation phenomena caused by thickness of iron plate and gap size between magnets. In case of iron plate, the vibration mode will be considered since vibration occurs during transportation. In order to solve the problems caused by vibration, choose the levitation system method using numbers of magnet, magnetic saturation for thickness and length of iron plate with parameters in location and gap of magnet. In this paper, we will suggest the whole design technique of magnetically levitated transportation system, namely method of magnetic attraction and transportation system

• International Journal of Automotive Technology
• /
• v.7 no.6
• /
• pp.749-756
• /
• 2006

This paper presents a complex stochastic wheelbase preview control method of a motorcycle suspension based on hierarchical modeling method. As usual, a vehicle suspension system is controlled as a whole body. In this method, a motorcycle suspension with five Degrees of Freedom(DOF) is dealt with two local independent 2-DOF suspensions according to the hierarchical modeling method. The central dynamic equations that harmonize local relations are deduced. The vertical and pitch accelerations of the suspension center are treated as center control objects, and two local semi-active control forces can be obtained. In example, a real time Linear Quadratic Gaussian(LQG) algorithm is adopted for the front suspension and the combination of the wheelbase preview and LQG control method is designed for the rear suspension. The results of simulation show that the control strategy has less calculating time and is convenient to adopt different control strategies for front and rear suspensions. The method proposed in this paper provides a new way for the vibration control of multi-wheel vehicles.

• Journal of the Korean Society for Precision Engineering
• /
• v.30 no.9
• /
• pp.915-921
• /
• 2013

Most of large scale solar panel handling robots adopt the timing-belt drive system for its driveline because of the simplicity and the easiness of implementation. The vibration caused by the flexure of the timing belt would increase as the size and the weight of the panel that the robot handles increase and the vibration would deteriorate the precision and/or productivity of the whole robot system. For the development of a proper control system and for the improvement of the design of the robot it is important to estimate the oscillatory response of the robot system including the flexible drive system properly. In this paper a flexible multi-body dynamics model of a large-scale solar-panel-handling robot with the flexible timing-belt drive system is developed using a generic multi-body dynamics analysis program, RecurDyn.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.25 no.6
• /
• pp.414-419
• /
• 2015

Recently, commercial ships and other specialized vessels with electric propulsion system employ variable speed induction motor as its prime mover. The wide application of electrical motors also includes being the main drive system in most industrial machineries. However, during its start-up, shutdown, and brake switch operation, excessive torque variation are generated. As such, flexible coupling are installed in order to reduce the transmitted torque fluctuation to the driven side. In this paper, the pulse torque generated by an variable speed induction motor was analyzed theoretically and through measurement of torsional vibration. Induction motor with inverter on marine propulsion system and industrial compressor were used as experimental subjects. The study confirmed that pulse torque are generated regardless of motor speed and interpreted as a vibration source of the whole system. Results presented herein can be adopted as the basis in future amendment of inspection classifying body regulations.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.15 no.2
• /
• pp.50-57
• /
• 2007

Shocks are excited by impulsive forces and cause discomfort in vehicles. Current standards define means of evaluating shocks and predicting their discomfort, but the methods are based on research with a restricted range of shocks. This experimental study was designed to investigate the discomfort of seated subjects exposed to a wide range of vertical shocks. Shocks were produced from the responses of one degree-of-freedom models, with 16 natural frequencies (from 0.5 to 16 Hz) and four damping ratios (0.05 0.1, 0.2 and 0.4), to a hanning-windowed half-sine force inputs. Each type of shock was presented at five vibration dose values in the range $0.35\;ms^{-1.75}$ to $2.89\;ms^{-1.75}$. Fifteen subjects used magnitude estimation method to judge the discomfort of all shocks. The exponent in Stevens' power law, indicating the rate of growth in discomfort with shock magnitude, decreased with increasing fundamental frequency of the shocks. At all magnitudes, the equivalent comfort contours showed greatest sensitivity to shocks having fundamental frequencies in the range 4 to 12.5 Hz. At low magnitudes the variations in discomfort with the shock fundamental frequency were similar to the frequency weighting $W_b$ in BS 6841, but low frequency high magnitudes shocks produced greater discomfort than predicted by this weighting. At some frequencies, for the same unweighted vibration dose value, there were small but significant differences in discomfort caused by shocks having different damping ratios. The rate of increase in discomfort with increasing shock magnitude depends on the fundamental frequency of the shock. In consequence, the frequency-dependence of discomfort produced by vertical shocks depends on shock magnitude. For shocks of low and moderate discomfort, the current methods seem reasonable, but the response to higher magnitude shocks needs further investigation.