• Korean Journal of Applied Biomechanics
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• v.23 no.1
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• pp.85-90
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• 2013

Efficient gait is compensate for a lack of exercise, but the wrong walking can cause disease that joints, muscles, brain and body structure(Scott & Winter, 1990). Also many researchers has been studied gait of positive mechanism using analytical methods kinetic, kinematic. This study is to identify nature of knee adduction moment, depending on different foot progression angle and the movement of rotation of pelvis and body. Health study subject conducted intended walking with three different angles. The subjects of this study classified three types of walking; walk erect, pigeon-toed walk and an out-toed gait. Ten university students of K without previous operation and disease record selected for this study. For accuracy of this study, three types of walking carried out five times with 3D image analysis and using analysis of ground reaction force to analyze nature of knee adduction moment and the movement of rotation of pelvis and body. Firstly, the HC(heel contact) section value of intended walk erect, pigeon-toed walk and an out-toed gait was not shown statistically significant difference but TO(toe off) section value was shown that the pigeon-toed walk statistically significant. The value of pigeon-toed walk was smallest knee adduction moment(p< 0.005). Secondly, X axis was the change of rotation movement body and pelvis when walk erect, pigeon-toed walk and an out-toed gait. Shown statistically Y axis was not shown statistically significant but Z axis statistically significant(p<0.05). These result show the significant differences on TO section when walking moment reaches HC, it decides the walking types and rotates the foot.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.131-140
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• 2014

The purpose of this study was to kinetic analysis of using the skill of breathing korean dance movement will be to perform. To achieve the research objectives cheoyongmu Nakhwayousu the operation was performed. The selection of subjects like the following: Five people were skilled use of breathing and five unskilled person. The results are as follows. The skilled and the unskilled were no significant differences in the duration time. And the skilled and the unskilled z-axis position of the center of mass, there was a significant difference (p<.05). The skilled and the unskilled y-axis velocity of the center of mass, there was a significant difference of event 1 and event 4 (p<.05). And z-axis velocity of the center of mass, there was a significant difference of event 3 (p<.05). And the skilled and the unskilled Fx of GRF, there was a significant difference of event 2 and event 4 (p<.05). And Fy of GRF, there was a significant difference of event 1 and event 5 (p<.05). And Fz of GRF, there was a significant difference of event 4 (p<.05).

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.120-130
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• 2014

The purpose of this study was to evaluate the effects of line dance activity on the balance factors during static standing to reveal the exercise intervention for fall prevention. A 15-week line dance programme was applied to 16 elderly females who aged more than 65 years in the community. Balance ability during static standing was evaluated by the range of center of pressure(cop), the velocity of cop, and sway area that calculated on the basis of ground reaction force data, forces, and moments. The range and velocity of cop in the anterio-posterior were significantly reduced after line dance(p<.01, p<.05, respectively), but change in those of cop in the medio-lateral was not found. It was demonstrated that 16-week line dance activities allow more effective in anterio-posterior stability and sway area of static standing. It was suggested that the effect of fall prevention exercise should be studied more associate with fall from vestibular and sensory system as future study.

• Korean Journal of Applied Biomechanics
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• v.24 no.4
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• pp.391-397
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• 2014

The purpose of this work is to biomechanically study the effect of the one leg standing pose in yoga.. The work have been done through the evaluation for the left and right symmetry ability of one leg standing pose in the before and after yoga training for the 14 female yoga subject group (height: $164.3{\pm}4.4cm$, mass: $53.4{\pm}6.4kg$, year: $20.0{\pm}0.49yrs$) participated in this experiment. The motions of one leg standing pose were captured with Vicon system and the parameters were calculated with Visual-3D and Ground reaction force system. The results were as followed; - Front and backward COPsd did not show the significant difference, compared the before training with the after. - Left and right COPsd showed the significant difference (p<0.05), compared the before training with the after. - COP distance showed the significant difference (p<0.01), compared the before training with the after. - The asymmetry index of front and backward COPsd did not show the significant difference, compared the before training with the after. - The asymmetry index of left and right COPsd did not show the significant difference, compared the before training with the after. - The asymmetry index of COP distance showed the significant difference (p<0.01), compared the before training with the after. Therefore, the yoga training demonstrated the stable improvement in the one leg standing pose of inferior feet and the positive effect to the left and right symmetry ability.

• Korean Journal of Applied Biomechanics
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• v.23 no.2
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• pp.179-187
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• 2013

This case study was conducted to determine the effects of water exercise on the foot pressure distribution (FPD) of persons who have a hemiplegia. A 43-year old female with hemiplegia acquired at the age of 3 years was selected from a local disability program. A 12-week water exercise program (60 min. per session and twice a week) focusing on gait training was developed and implemented as the intervention of this study. A recent product of the Pedar-X (Novel, Germany) was used to measure the FPD of hemiplegic gait before and after the intervention. Variables considered in this study included the average pressure (AP), contact area (CA), maximum pressure (MP), ground reaction force (GRF), and center of pressure (COP). The data collected were analyzed via the descriptive statistics and qualitative analyses on the graphical presentations of the FPD. Results revealed that the AP and CA of the hemiplegic foot was considerably increased before and after the intervention. Similar results were also found in the MP and GRF. Additionally, the graphical route of the COP related to hemiplegic foot was changed in a positive way after the intervention. It can be concluded that water exercise may be beneficial to restore hemiplegic gait. Limitations related to measurement and generalizability are further discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.3834-3842
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• 2011

The purpose of this study is to analyze the kinematic characteristics of children with Down syndrome got congenitally joint laxity and muscle hypotonic. The subjects are boys with Down syndrome and don't have the other disabilities. We got three dimensional position data and then calculated spatiotemporal and kinematic variables during walking on treadmill used increasingly for gait analysis and training. In result, in order to overcome their gait instability due to their musculoskeletal characteristics they walked with hip, knee and ankle joints more flexed than the typical gait pattern, and on the propulsion phase they extend the lower limb joints less than the typical, result in propel the body less than. The reason is that the more is the propulsion by extending the joints, the greater is the reaction force from the ground on heel contact. This result is expected to be used to develop the training program for intensification of musculoskeletal system aim to improve the other musculoskeletal disabilities as well as Down syndrome.

• The Journal of Korea Robotics Society
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• v.17 no.3
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• pp.296-302
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• 2022

This paper proposes a center of plantar foot pressure (CoP) trajectory estimation method based on Gaussian process regression, with the aim to show robust results regardless of the regions and numbers of FSRs of the insole sensor. This method can bring an interpolation between the measurement points inside the wearable insole sensor, and two experiments are conducted for performance evaluation. For this purpose, the input data used in the experiment are generated in three types (13 FSRs, 8 FSRs, 5 FSRs) according to the regions and numbers of FSRs. First, the estimation results of the CoP trajectory are compared using Gaussian process regression and weighted mean. As a result of each method, the estimation results of the two methods were similar in the case of 13 FSRs data. On the other hand, in the case of the 8 and 5 FSRs data, the weighted mean varies depending on the regions and numbers of FSRs, but the estimation results of Gaussian process regression showed similar results in spite of reducing the regions and numbers. Second, the estimation results of the CoP trajectory based on Gaussian process regression during several gait cycles are analyzed. In five gait cycles, the previous cycle and the current estimation results are compared, and it was confirmed that similar trajectories appeared in all. In this way, the method of estimating the CoP trajectory based on Gaussian process regression showed robust results, and stability was confirmed by yielding similar results in several gait cycles.

• Physical Therapy Korea
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• v.31 no.1
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• pp.29-39
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• 2024

Background: Landing from a step or stairs is a basic motor skill but high incidence of lateral ankle sprain has been reported during landing with inverted foot. Objects: This study aimed to investigate the effect of landing height and visual feedback on the kinematics of landing and supporting lower limbs before and after the touch down and the ground reaction force(GRF)s. Methods: Eighteen healthy females were voluntarily participated in landing from the lower (20 cm) and the higher (40 cm) steps with and without visual feedback. To minimize the time to plan the movement, the landing side was randomly announced as a starting signal. Effects of the step height, the visual feedback, or the interaction on the landing duration, the kinematic variables and the GRFs at each landing event point were analyzed. Results: With eyes blindfolded, the knee flexion and ankle dorsiflexion on landing side significantly decreased before and after the touch down. However, there was no significant effect of landing height on the anticipatory kinematics on the landing side. After the touch down, the landings from the higher step increased the knee flexion and ankle dorsiflexion on both landing and supporting sides. From the higher steps, the vertical GRF, anterior GRF, and lateral GRF increased. No interaction between step height and visual feedback was significant. Conclusion: Step height and visual feedback affected the landing limb kinematics independently. Visual feedback affected on the landing side while step height altered the supporting side prior to the touch down. After the touch down, the step height had greater influence on the lower limb kinematics and the GRFs than the visual feedback. Findings of this study can contribute to understanding of the injury mechanisms and preventing the lateral ankle sprain.

• Physical Therapy Rehabilitation Science
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• v.13 no.2
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• pp.152-162
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• 2024

Objective: This study was conducted to analyze the effect of wearable Electromyography-controlled functional electrical stimulation (EMG-controlled FES) System on Gait Function and cardiopulmonary metabolic efficiency during walking in older adults. Design: Cross-section study Methods: Total 22 older adult participants suitable to selection criteria of this study participated in this study. The EMG-controlled FES System, which functions as a wearable physical activity assist FES system was used. All participations performed randomly assigned two conditions (Non-FES assist [NFA], FES assist [FA]) of walking. In all conditions, spatio-temporal parameters and kinematics and kinetics parameters during walking was collected via 3D motion capture system and 6 minutes walking test (6MWT) and metabolic cost during walking and stairs climbing was collected via a portable metabolic device (COSMED K5, COSMED Srl, Roma, Italy). Results: In Spatio-temporal parameters aspects, The EMG-controlled FES system significantly improved gait functions measurements of older adults with sarcopenia at walking in comparison to the NFA condition (P<0.05). Hip, knee and ankle joint range of motion increased at walking in FA condition compared to the NFA condition (P<0.05). In the FA condition, moment and ground reaction force was changed like normal gait during walking of older adults in comparison to the NFA condition (P<0.05). The EMG-controlled FES system significantly reduced net cardiopulmonary metabolic energy cost, net energy expenditure measurement at stairs climbing (P<0.05). Conclusions: This study demonstrated that EMG-controlled FES is a potentially useful gait-assist system for improving gait function by making joint range of motion and moment properly.

• Korean Journal of Applied Biomechanics
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• v.21 no.1
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• pp.31-38
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• 2011

This study aimed to determine the effects of the blockage of visual feedback on joint dynamics of the lower extremity. Fifteen healthy male subjects(age: $24.1{\pm}2.3\;yr$, height: $178.7{\pm}5.2\;cm$, weight: $73.6{\pm}6.6\;kg$) participated in this study. Each subject performed single-legged landing from a 45 cm-platform with the eyes open or closed. During the landing performance, three-dimensional kinematics of the lower extremity and ground reaction force(GRF) were recorded using a 8 infrared camera motion analysis system (Vicon MX-F20, Oxford Metric Ltd, Oxford, UK) with a force platform(ORG-6, AMTI, Watertown, MA). The results showed that at 50 ms prior to foot contact and at the time of foot contact, ankle plantar-flexion angle was smaller(p<.05) but the knee joint valgus and the hip flexion angles were greater with the eyes closed as compared to with the eyes open(p<.05). An increase in anterior GRF was observed during single-legged landing with the eyes closed as compared to with the eyes open(p<.05). Time to peak GRF in the medial, vertical and posterior directions occurred significantly earlier when the eyes were closed as compared to when the eyes were open(p<.05). Landing with the eyes closed resulted in a higher peak vertical loading rate(p<.05). In addition, the shock-absorbing power decreased at the ankle joint(p<.05) but increased at the hip joints when landing with the eyes closed(p<.05). When the eyes were closed, landing could be characterized by a less plantarflexed ankle joint and more flexed hip joint, with a faster time to peak GRF. These results imply that subjects are able to adapt the control of landing to different feedback conditions. Therefore, we suggest that training programs be introduced to reduce these injury risk factors.